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DIY Stompboxes => Building your own stompbox => Topic started by: frequencycentral on August 18, 2008, 03:35:10 PM

Title: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 18, 2008, 03:35:10 PM
A few people have asked me about a single speed pot version of the "Bipolar Disorder" (http://www.diystompboxes.com/smfforum/index.php?topic=69334.0), so here it is, the "Vibracaster".

The tube section is basically the Valvecaster schematic. I prefer a 100K 'Gain' pot - but maybe a tremolo doesn't need overdrive too? So, the gain pot can be ditched and replaced with a 100K resistor.

With the 'Depth' pot turned down it's just a standard Valvecaster.

If you want it even 'cleaner' you can replace the 220k resistor at 12AU7 pin 1 with 100k, and the 100k resistor at 12AU7 pin 6 with 47k.

The LFO section is a phase shift oscillator - many thanks to R.G. for helping me to understand how they work.

This is on my breadboard and working right now, I'm using a 6111 submini tube on the breadboard, but it will work identically with a 12AU7.

I wanted to breadboard a phase shift oscillator for another project I'm working on. Then it occured to me that it would be perfect for a "Vibracaster" too. I wasn't going to actually make it into a pedal, but I guess I will - I like it a lot! I'm going to build it with a submini 6111 in a tiny enclosure, I won't bother with the gain control.

Oooooh! I hope someone esle builds it too!

EDIT: Oh, and I hooked up a 'Rate' LED (via a 4K7 resistor) from the emitter of the second transistor (the one on the right). The LED kathode goes directly to earth, obvioulsly.

(http://i210.photobucket.com/albums/bb292/frequencycentral/Vibracaster.jpg)

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on August 18, 2008, 04:29:06 PM
Neat!

I really wanna build one now.

(http://img170.imageshack.us/img170/1011/vibracastertd6.gif)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 18, 2008, 04:38:23 PM
Neat!

I really wanna build one now.

Wow! That was quick work Chris!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Darkness, Darkness on August 18, 2008, 04:41:37 PM

I still have to finish my distortion box first (no much time, need to order some parts to try ... again....the project is going ahead slowly...) but that one is second on my list ! Please continue to be creative around low voltage tube design : they sound so good (maybe "not as much" as tubes running at real voltage but they sound damn good !) I really was wanting a tube tremolo thing, something like a Deluxe Reverb or Vox AC30... how this one compared to these others ?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on August 18, 2008, 04:45:27 PM
Neat!

I really wanna build one now.

Wow! That was quick work Chris!
Haha it was..

Once I finish debugging and building 3 amps and 9 effects and my Valve Caster that are on my bench now I am going to build this unit!

How are you liking it so far? What's it sound like?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 18, 2008, 04:49:01 PM
I really was wanting a tube tremolo thing, something like a Deluxe Reverb or Vox AC30... how this one compared to these others ?

I think it has a cool vintage sound, but then I'm baised - I'm it's Dad!

I don't have an AC30 or Deluxe Reverb to compare it to (any contributions gratefully recieved), but theoretically is should sound similar. I'm pretty sure most vintage amps used tube phase shift oscillators to create tremolo, the Vibrocaster just has the transistor oscillator because tubes won't oscillate at low voltage. The phase shift oscillator is one of the oldest tricks in the book, invented soon after R.G. first created electricity.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: comfortably_numb on August 18, 2008, 05:01:38 PM
If one were to want to insert this LFO into say, a vanilla overdrive, which has a bit different topology than the Valvecaster, how would it be done?  Would you connect the wiper of the the depth pot to a cathode resistor in the OD circuit?  Or does it have to be directly connected to the cathode to work properly?  And what difference does it make which triode you use?  I notice that your Bipolar Disorder is almost a backwards valvecaster.  Why did you design this way?

Sorry for all the questions, I just like to have my head around the theory before I undertake a build.

Thanks
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 18, 2008, 05:24:31 PM
If one were to want to insert this LFO into say, a vanilla overdrive, which has a bit different topology than the Valvecaster, how would it be done?  Would you connect the wiper of the the depth pot to a cathode resistor in the OD circuit?  Or does it have to be directly connected to the cathode to work properly?

The last triode in the Vanilla Overdrive is non-inverting, so you would be sending the LFO directly to the output - that might not be good! The reason it works so well with the Valvecaster schematic is that the second triode is normally directly connected to earth, so with the depth at minimum it's just a normal Valvecaster. Also, the output of the Valvecaster is from the plate, so the LFO doesn't go directly to the output. I experimented with bootstrapping (resistor and electro cap in parallel) the cathode which recieves the LFO, but the results were a lot better without. I don't think just hooking up the LFO to either the Vanilla Overdrive or the Pepper Shredder would work as well as this circuit. You would have to breadboard it and experiment.

And what difference does it make which triode you use?  I notice that your Bipolar Disorder is almost a backwards valvecaster.  Why did you design this way?

Yeah, it's the other way round in the BD. That was because I was having problems with LFO bleed, which i combatted by using the 0.01 cap and the 100K resistor between the two triodes as a highpass filter, to get rid of the thump. The Vibracaster doesn't suffer with the same problems, probably because the LFO waveform in the BD was kinda triangle, while the LFO waveform in the Vibracaster in more a sine.

You also have to bear in mind that I'm really a complete idiot masquerading as an elecronics engineer.

***********************************************************************************************************************************************

I just recorded a soundclip, but I have no idea how to post it, I've added it to my 'Builds' Myspace (in my signature bit, below), but it won't be uploaded onto the Myspace page for at least 24 hours. It was recorded directly into Wavelab through my soundcard, an Event Echo Gina 24, with no other processing. If anyone can tell me how, i will add the soundclip to this thread - PM me!
Title: Vibracaster
Post by: Renegadrian on August 18, 2008, 07:33:55 PM
Rick, it seems you do like tubes!!!  :icon_wink:
I will try your circuit in a couple of weeks...Gotta wait some parts I ordered...
I will surely report it then!!!  :icon_wink:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on August 18, 2008, 07:59:03 PM
You could wire this circuit to be a double pedal me thinks...

Wire it like standard true bypass and you go a trem pedal.

Add a SPST switch to break the connection to the second triodes cathode and you got a trem pedal that can be switchable to a booster/overdrive pedal.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: andrew_k on August 18, 2008, 08:10:05 PM
Love it. I'll be trying this one out on a breadboard in the next week for sure.

Would a 2N3904 be a suitable replacement for the BC547?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: dxm1 on August 18, 2008, 10:59:05 PM
Would a 2N3904 be a suitable replacement for the BC547?

I dunno - a 2N3904 would have a max Hfe around 300. The BC547 is about 800.  Maybe a 2N5089 would be a better sub...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: andrew_k on August 18, 2008, 11:49:28 PM
The BC547 is about 800.

Ah, the data sheet I read said 300hFE for the 547... Maybe I was looking at the wrong column (it was one of those many-items-in-one data sheets). I'll try higher gain transistors first. Thanks  :)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: dxm1 on August 19, 2008, 12:25:18 AM
Ah, the data sheet I read said 300hFE for the 547...

The OP doesn't specify -a, -b, or -c version.  I think a -b would be close to a 2N3904...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Jimmy-H on August 19, 2008, 12:37:15 AM
you have been very busy Rick!! :icon_wink:
Now I have to choose between two tremolo's
Great work again!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 19, 2008, 06:51:24 AM
You could wire this circuit to be a double pedal me thinks...

Wire it like standard true bypass and you go a trem pedal.

Add a SPST switch to break the connection to the second triodes cathode and you got a trem pedal that can be switchable to a booster/overdrive pedal.

Yeah, I was thinking the same as I drifted off to sleep last night. Or you could have no bypass at all - just two footswitches, one to hardwire the gain for maximum resistance or the gain pot, the other to hardwire the depth to earth or the pot.

Love it. I'll be trying this one out on a breadboard in the next week for sure.

Would a 2N3904 be a suitable replacement for the BC547?
Ah, the data sheet I read said 300hFE for the 547...

The OP doesn't specify -a, -b, or -c version.  I think a -b would be close to a 2N3904...

I used BC547C. R.G. says that the oscillator wont start up with low gain transistors. If you use other transistors you should socket them so you can change them out if the oscillator doesn't fire up.

Also, see this thread for the design of the oscillator: http://www.diystompboxes.com/smfforum/index.php?topic=70056.0

you have been very busy Rick!! :icon_wink:
Now I have to choose between two tremolo's
Great work again!

Build this one Jimmy, the Bipolar Disorder is a lot more pain for not much more gain. The BD took ages to iron out problems with, LFO bleed and thump, the Vibracaster just worked well first time. Also, the parts count for the Vibracaster is just tiny in comparison with the BD.


***********************************************************************************************************************************************


I forgot to mention - I used a 10uf electro cap across the power rails to decouple and smooth. Positive end of the cap to 12 volts, negative end to earth, preferably where the power goes into the circuit.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Salvatore on August 19, 2008, 08:05:12 AM
Very sweet design Rick, simple and efficient.
Have listened to you're sound clip on myspace, and I love it.
Bet this could be a great swell pedal to if you replace the lfo by a simple (attack, threshold) env.gen.
On my build list. :icon_cool:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 19, 2008, 08:17:40 AM
Very sweet design Rick, simple and efficient.
Have listened to you're sound clip on myspace, and I love it.
Bet this could be a great swell pedal to if you replace the lfo by a simple (attack, threshold) env.gen.
On my build list. :icon_cool:

Thank you. Yes, I have been thinking about using something similar as VCAs in my modular synth system. It would have to be an inverted envelope though, as the tube 'VCA' is open at 0 volts. I have plenty of envelope generators - I just haven't got round to doing that experiment yet. I've also got an idea for a tube filter pedal - I found a great schematic here: http://electro-music.com/forum/viewtopic.php?highlight=tube+vcf&t=23067 I ordered the 5672 tubes, they're here, I just have to get around to it - it's planned in my head if you know what I mean - A/R envelope with initiate momentary footswitch, envelope follower, tri/square LFO, sample and hold.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Salvatore on August 19, 2008, 08:53:10 AM
Great !!! :icon_biggrin:

I have been eying Jeroen Baars his designs, he's planning to do a complete modular system, most of it not based on tubes.
He did also made a tube vca based on the same 5672 tube.
http://www.synthforum.nl/forums/showthread.php?t=90425&page=2
(Glad I can speak Dutch)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 19, 2008, 09:16:10 AM
Great !!! :icon_biggrin:

I have been eying Jeroen Baars his designs, he's planning to do a complete modular system, most of it not based on tubes.
He did also made a tube vca based on the same 5672 tube.
http://www.synthforum.nl/forums/showthread.php?t=90425&page=2
(Glad I can speak Dutch)

Yeah, I'm planning to make the 5672 VCA too - you should translate the whole thing for me - the only Dutch I know is "Let Op! Drempels!"
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: MikeH on August 19, 2008, 10:37:41 AM
Looks awesome!  I'm going to make a little add-on board and make this a switchable mod.  Looks cool.  Does it behave the same @ 12v vs 9v?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 19, 2008, 10:42:56 AM
Looks awesome!  I'm going to make a little add-on board and make this a switchable mod.  Looks cool.  Does it behave the same @ 12v vs 9v?

I breadboarded the oscillator at 9 volts, It seems to work the same at 12 volts. Tubes circuits definately work better at higher voltages!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Salvatore on August 19, 2008, 10:47:01 AM
Yeah, I'm planning to make the 5672 VCA too - you should translate the whole thing for me - the only Dutch I know is "Let Op! Drempels!"

Well, at least you know some relevant Dutch, "watch out ! Thresholds". :icon_lol:
If you want I could translate the interesting bits, that would not be to much work.
But I could not start until at least a week from now, bit busy at the moment with a new band.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: jacobyjd on August 19, 2008, 10:48:41 AM
I may have missed it above, but I know most are running their Valvecasters at 12v (or higher)--would 12v be too much for running this add-on?

heh, never mind :)  Too fast for me!  :icon_neutral:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Jimmy-H on August 19, 2008, 01:37:37 PM

Build this one Jimmy, the Bipolar Disorder is a lot more pain for not much more gain. The BD took ages to iron out problems with, LFO bleed and thump, the Vibracaster just worked well first time. Also, the parts count for the Vibracaster is just tiny in comparison with the BD.


OK Rick, I'll keep that in mind.
By the way, I just listened to your recording of the pedal, sounds great!
Keep up doin' the good work  ;)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: nokaster on August 19, 2008, 02:18:18 PM
"Let Op! Drempels!"


being belgian... this was a very funny read!
weird which phrases end up as the only one someone knows in a certain language!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 21, 2008, 01:41:07 PM
Here's a schematic for the Vibracaster with pinouts and heater circuit if you want to use a 6111 submini tube instead of a 12AU7:

(http://i210.photobucket.com/albums/bb292/frequencycentral/Vibracaster6111.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Fl!P on August 21, 2008, 03:34:13 PM
Well done!

But, uh... Excuse me for asking, but can I get some sound clips?

 ;D
Title: SOUND CLIPS
Post by: Renegadrian on August 21, 2008, 03:43:01 PM
http://www.myspace.com/doctoranalogue  :icon_wink:
Title: Re: SOUND CLIPS
Post by: Fl!P on August 21, 2008, 03:47:24 PM
http://www.myspace.com/doctoranalogue  :icon_wink:

Thanks!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: comfortably_numb on August 21, 2008, 05:18:13 PM
I'd like to take the opportunity to point out that the 12AU7 heaters can be run in parallel at 6.3 volts as well, and so any of these circuits can be safely used at 9V with the heaters in parallel following frequencycentral's voltage drop technique.  The 12U7 data sheet does not specify a parallel heater voltage, but as there is a center tap (pin 9) I imagine it would function similarly.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on August 21, 2008, 05:53:03 PM
yeah, I remember it was discussed in the main valvecaster topic...the way you can use pin 9  and what it's for...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 21, 2008, 06:05:25 PM
I'd like to take the opportunity to point out that the 12AU7 heaters can be run in parallel at 6.3 volts as well, and so any of these circuits can be safely used at 9V with the heaters in parallel following frequencycentral's voltage drop technique.  The 12U7 data sheet does not specify a parallel heater voltage, but as there is a center tap (pin 9) I imagine it would function similarly.

Might need a recalculation for the series resistor value @ 9 volts though.  :icon_wink:
Title: Vibracaster
Post by: Renegadrian on August 26, 2008, 03:29:35 AM
Hey Rick, I have some BC 548, both B and C - would they fit? Or should I stick to the 547s you used???
Also, why did you use a 100k LIN and not LOG for VOLUME? And why a 100k for the GAIN, instead of the 50K of the original?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 26, 2008, 06:45:26 AM
Hey Rick, I have some BC 548, both B and C - would they fit? Or should I stick to the 547s you used???
Also, why did you use a 100k LIN and not LOG for VOLUME? And why a 100k for the GAIN, instead of the 50K of the original?

Just comparing the BC547C with the BC548C on their datasheets, they appear to have the same gain, the 'B' version has too little gain though, and probably wouldn't be suitable. You should socket the transistors though, just in case they don't work for some reason.

Volume - I'm going to build mine with a trimpot or resistor voltage divider (to achieve unity between the bypassed and effected signals) instead of a Volume control - you don't usually see tremolos with volume controls. As to 'why Lin and not Log', I've built a lot of synth stuff, where Lin in used for signals and Log for control voltages. Different pot manufacturers label their pots differently too, an 0MEG Lin is 'A', an Alpha Lin is 'B' - very confusing.

Gain - having a 100K instead of a 50K allows more resistance between the cathode and ground, and therefore more clean headroom. Again, I'm building mine without a gain control, I'll use a 100K resistor instead - you don't ususally see tremolos with gain controls either. I will also be using 100K resistors for both the plate resistors, again aiming for a clean sound.

So mine will just have two pots - 'Speed' and 'Depth'.

I've also made a few improvements to the design - just tweaks here and there - and one of the resistor values I posted was wrong (doh! - the first 4K7 at the emitter of the second transistor should be 47K), so hold off from building it for a day or two, to give me time to update the schematic.
Title: thx
Post by: Renegadrian on August 26, 2008, 08:18:03 AM
Well, I usually use sockets, so no problems...I'll try those BC548C

You wrote that with the depth pot at zero you have a standard valvy, right?
So I want to build it with all the pots then...
I'd have a standard valvy and a tremolo at the twist of that pot?
The way you'd do it it would use valvy part just to clean boost the sound...

Wait for the updates then!!! Thx for your useful explaination!!!  :icon_wink:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 26, 2008, 11:04:22 AM
Here's the latest update, it's the version I'll be building. It's the 6111 submini version with no gain control and no volume control. I'm building mine as a tremolo only - no boost/overdrive - just unity gain between the bypassed and effected signals. Tremolos don't usually have gain/volume controls.

The tweaks are circled in red. (though somehow it seems to have changed to purple in Photobucket)

A. I've changed the gain pot for a 100K resistor - for hardwired clean headroom.

B. I've changed the 100K plate resistor for a 220K - to achieve unity gain between the bypassed and effected signals.

C. I've added a 1N4148 to negate a bit of LFO bleed I found.

D. This was 4K7 on the original schematic. It was a mistake! Oops! It should be 47K.

I'm still having problems adding a rate LED - it flashes nicely but it causes audible ticking - I've tried a few solutions (including Jack Orman ones) with no luck. I guess a rate LED isn't essential - but I won't let it beat me - so I will post the solution when I find it.

(http://i210.photobucket.com/albums/bb292/frequencycentral/Vibracaster6111V2.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 26, 2008, 01:29:15 PM
..........and here, finally, is the way to add the LFO rate LED without causing any popping.

(http://i210.photobucket.com/albums/bb292/frequencycentral/LEDMod.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on August 26, 2008, 02:05:17 PM
so it should be that way? What is that 100k res at the base? Also, will this circuit work as a stand-alone (without the tube part) or it needs something to boost the sound???

(http://img222.imageshack.us/img222/4962/vibracastercg8.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 26, 2008, 02:20:56 PM
so it should be that way? What is that 100k res at the base? Also, will this circuit work as a stand-alone (without the tube part) or it needs something to boost the sound???

Sorry - I don't understand the question.............???

EDIT: Aah - got it! No way Adriano - that arrangement would tick like a Swiss cuckoo clock at midnight! The LED circuit uses an EXTRA transistor. Like this:

(http://i210.photobucket.com/albums/bb292/frequencycentral/Vibracaster6111V2-2.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Franky on August 26, 2008, 07:50:05 PM
Wow, this project rocks!! I think i'm gonna have to design a 12V power supply for all those nice tube projects..  :icon_rolleyes:  :icon_wink:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 27, 2008, 04:26:21 PM
Here's mine:

(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0384-1.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on August 27, 2008, 04:28:55 PM
Nice!

What did you build it on? Perf, vero?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 27, 2008, 04:34:44 PM
Nice!

What did you build it on? Perf, vero?

Tripad - three holes per pad. I really like it a lot!

(http://i210.photobucket.com/albums/bb292/frequencycentral/jp52g.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Franky on August 27, 2008, 07:15:04 PM
It looks great! Good work man!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: col on August 28, 2008, 04:00:17 PM
I need to try that oscillator in a tremelo circuit I've been messing with to see if it cuts out the thump I was getting, not even a tick. What we really need for true vintage mojo is a Ge transistor oscillator. I have tried a few but they have produced ticking, I wonder if this could be adapted to remove it?

Col
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Franky on August 28, 2008, 04:06:48 PM
I was just about to talk about that oscillator.. In a different way, using an opamp to get more waveshapes (tri or square, or even a mix)...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 28, 2008, 07:45:47 PM
I need to try that oscillator in a tremelo circuit I've been messing with to see if it cuts out the thump I was getting, not even a tick. What we really need for true vintage mojo is a Ge transistor oscillator. I have tried a few but they have produced ticking, I wonder if this could be adapted to remove it?

Col

Most of the ticking I had to fix was caused by the rate LED turning on and off, only a little from the LFO itself. I found the diode between the wiper of the depth pot and the cathode sorted that out, together with playing about with the values for the voltage divider at the LFO output.

As for Ge - they're really low gain as far as I know (I'm no expert), I think the BC547C I used has a gain of 800. I tried this oscillator with BC107's - it wouldn't oscillate.

I was just about to talk about that oscillator.. In a different way, using an opamp to get more waveshapes (tri or square, or even a mix)...

You could use a transistor or (opamp) comparator to turn the LFO's sine output into a square wave - but you may then experience ticking. Triangle is so similar to sine (for this purpose) that's it's not worth the extra hassle! And triangle would also probably have ticking problems. The LFO in my other tube tremolo 'Bipolar Disorder' was based on a triangle, I had to work hard to stop thumping/ticking. The nice thing about a sine is it's smooth turnaround.

What I like about the Vibracaster is it's 'vintageness' - old school tremolos used similar sine wave phase shift oscillators - this one just uses transistors instead of tubes. Tubes won't oscillate at 12 volts........
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 29, 2008, 11:08:08 AM
Finished:

(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0386.jpg)

(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0395.jpg)

(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0387.jpg)

(http://i210.photobucket.com/albums/bb292/frequencycentral/moto_0388.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Jimmy-H on August 29, 2008, 11:29:54 AM
OOOoops you did it again!
Nice piece of work Rick ;)
Does it sound different compared to the Bipolar disorder?

And you couldn't help yourself to build the Vibracaster! ;D


Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on August 29, 2008, 11:31:00 AM
(http://digilander.libero.it/le.faccine/faccinea/sorpreso/21.gif)(http://digilander.libero.it/le.faccine/faccinea/varie/407.gif)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 29, 2008, 11:57:05 AM
OOOoops you did it again!
Nice piece of work Rick ;)
Does it sound different compared to the Bipolar disorder?

And you couldn't help yourself to build the Vibracaster! ;D


Thanks Jimmy! I haven't done an A/B test with the Bipolar Disorder yet - I'll get around to it and post some more clips.

No - I had to build it really to get 'closure' - now I can move on to #3 in my submini tube series: "Doppelganger".

And...........if I hadn't built it I wouldn't have sorted out the bugs!

(http://digilander.libero.it/le.faccine/faccinea/sorpreso/21.gif)(http://digilander.libero.it/le.faccine/faccinea/varie/407.gif)

Hehehe - where you get those icons from I just don't know!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: liddokun on August 31, 2008, 11:15:45 AM
I can use the 6111 version 2 schematic, but just build it using a 12AU7 right?  The pinout's are just different, but all the resistor values and everything is ok staying the same?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 31, 2008, 11:30:25 AM
Here's the 12AU7 version, just the tube pinouts change. The rate LED circuit is optional.

(http://i210.photobucket.com/albums/bb292/frequencycentral/Vibracaster12AU7V2.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: liddokun on August 31, 2008, 11:34:02 AM
Alright, thanks a lot Rick.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: liddokun on August 31, 2008, 01:38:20 PM
The circuit can also be run at 9VDC, correct?  If I'm running it at 12V using a wallwart, what should the current specs be for it? 300mA?
And those two big resistors..if I'm building with 12AU7, then I can just use 1/4 watt resistors throughout?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 31, 2008, 04:03:01 PM
The circuit can also be run at 9VDC, correct? 

Correct - but it would have to be the 12AU7 version.

If I'm running it at 12V using a wallwart, what should the current specs be for it? 300mA?

12AU7 version should draw about 150ma.

6111 version should draw about 300ma.

Make sure your power supply is regulated. Maybe you should get a 500ma (or more) so you can power future tube projects.

And those two big resistors..if I'm building with 12AU7, then I can just use 1/4 watt resistors throughout?

You only need the big resistor(s) for the 6111 version. To run the 6111 heater from 12 volts you need to reduce it to 6.3 volts. That's what the 19 ohm / 3 watt resistor does. I used two 10 ohm in series - they were 5% tolerance,  I measured them at 19 ohms - perfect!

Alternatively you could use a 7806 voltage regulator (6 volts is at the lower end of the heater tolerance, but it should be fine). Or you could use a LM317 and trimmer (like the Subcaster) and dial it in to 6.3 volts.

Don't forget you could also add all the original Valvecaster controls with a bit of tweaking: Gain, Tone, Volume. I will add a schematic of that version to this thread eventually - but it's pretty easy to work out if you compare the schematics.

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: liddokun on August 31, 2008, 04:08:00 PM
Hey, thanks for the help.  I saw a few tweaks in the valvecaster forum, specifically using the 7812 on the dc jack with 100uf filtering cap.  Should I add this on the vibracaster?  I'm planning on doing it 9vdc, with a 12AU7 so that I can power it off my daisy chain.  The 7812 is a 12v regulator, so I suppose I wouldn't use it here for my 9v circuit. 
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Johnny Halo on August 31, 2008, 04:14:34 PM
Can someone post the PCB layout for this in the 12au7 version?

Thanks.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 31, 2008, 04:32:21 PM
Hey, thanks for the help.  I saw a few tweaks in the valvecaster forum, specifically using the 7812 on the dc jack with 100uf filtering cap.  Should I add this on the vibracaster?  I'm planning on doing it 9vdc, with a 12AU7 so that I can power it off my daisy chain.  The 7812 is a 12v regulator, so I suppose I wouldn't use it here for my 9v circuit. 

Don't bother with a 7812 if your'e running on 9 volts. Maybe you could consider a 7809 instead, but build it without first - you may not need it. Use the 100uf cap though.

Can someone post the PCB layout for this in the 12au7 version?

Thanks.

Sorry, i don't do PCB - I'm a Tripad guy (see above). Someone else is welcome to come up with a vero layout or a PCB though...............
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on August 31, 2008, 04:52:59 PM
The 7812 is a 12v regulator, so I suppose I wouldn't use it here for my 9v circuit. 

Use a 7809.  :icon_wink:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: liddokun on August 31, 2008, 05:15:42 PM
I'm going to do mine point to point.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: ACS on August 31, 2008, 06:41:23 PM
Built this one yesterday.  I think it doesn't know the words....


...'cos all it does is hum!!


OK, terrible joke.  But have got some debugging to do tonight.  Think it must be the Valvecaster portion of the circuit, so will start by isolating that and see how we get on...

Aidan

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 31, 2008, 06:45:37 PM
Built this one yesterday.  I think it doesn't know the words....


...'cos all it does is hum!!


OK, terrible joke.  But have got some debugging to do tonight.  Think it must be the Valvecaster portion of the circuit, so will start by isolating that and see how we get on...

Aidan



It must be a wiring error or power supply problem. I breadboarded this, then drew up the schematic. I built my finished pedal from the schematic - works better than the breadboarded version!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 31, 2008, 06:46:22 PM
ERROR REPORT:

I made a mistake in the 12AU7 version of the schematic - I numbered the first triode nodes incorrectly. I have deleted the incorrect schematic from Photobucket and re-uploaded the corrected schematic. From the top, the first triode nodes should now read 1, 2, 3.

It may take a few hours for the new schematic to show on page 3 of this thread - Photobucket is funny like that. Sorry if this caused anyone any hassles.

Rick

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Just to round off this project, here's a version with all the original Valvecaster controls, Gain, Tone, Volume.

I just changed the gain pot from 50K to 100K for more clean headroom, and changed the tone cap from 10nf to 47nf for a broader range of tones.

(http://i210.photobucket.com/albums/bb292/frequencycentral/VibracasterStock12AU7V2B.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Johnny Halo on September 01, 2008, 09:25:23 AM
How about a layout for ptp or perf board?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: liddokun on September 01, 2008, 10:45:58 AM
I'll see what I can do.  I was planning on doing ptp for the 12AU7 portion, and pcb for the tremolo add on. I'll post it when I'm done.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 01, 2008, 01:21:51 PM
Ok, Photobucket has now updated the schematics - so all the schematcis I have posted are correct. Phew!

I blame the error on my assistant, Igor, who does all the menial tasks around Castle Analogue.........
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 01, 2008, 01:38:52 PM
Ill update the verolayout on the first page and make a full layout at a later date. Too many other builds going on at the momnt and pesky school starting up again.

Damn cool effect, I got afew ideas for when I build it.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 12, 2008, 10:13:41 PM
Got a bit of free time and threw together a vero layout as I only build on vero and I want one of these units.

I cant find any errors... As you can see my layout isn't the best but like I say I cant find any errors.
(http://img529.imageshack.us/img529/2716/vibracasteriijl7.gif)

Note this is for a 12AU7 based unit. No mods other than a 33nF input cap which I find is just perfect!

(I have a layout with 5 more components for a rate LED if anyone wants it.)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 14, 2008, 07:08:49 PM
Bump

Can someone check that vero layout? It will take 5min as all you need to check is the oscillator. The tube portion is fine.

EDIT...spotted issue with Speed 3 area.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 15, 2008, 08:41:51 AM
Chris, I would check it myself but I never use stripboard - it would be an uphill task - Adriano could verify it way easier than me! Hint hint!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 15, 2008, 12:30:13 PM
Thats what I was hoping ;)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on September 15, 2008, 01:39:35 PM
I can do that but not at the moment...I need a couple of weeks...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: andrew_k on September 15, 2008, 05:56:06 PM
Chris: I'll check it over later today  :)
Title: First "EYE" check of the VERO
Post by: Renegadrian on September 15, 2008, 06:10:19 PM
First "EYE" check of the VERO

Tht's what I can do for now, as I haven't got all the parts needed to build that - It seems quite correct at a first glance, maybe I am not so sure about that SPEED 3, as you wrote...It should be 47k res-->SPEED pot lug 3 and LUG 1&2-->ground.
I'd erase that jumper to ground...

Also...You didn't write that the last track is for ground too, so it should be connected to the other ground track - maybe it's the same long jumper that doesn't go the the track labelled "l" but to the last labelled "o"
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 15, 2008, 06:11:00 PM
Thanks Andrew! ;)

The tube section (top half) is Adriano's vero layout. Its the connection to the oscillator and the oscillator that need checking.
Title: Re: First "EYE" check of the VERO
Post by: kurtlives on September 15, 2008, 06:12:08 PM
First "EYE" check of the VERO

Tht's what I can do for now, as I haven't got all the parts needed to build that - It seems quite correct at a first glance, maybe I am not so sure about that SPEED 3, as you wrote...It should be 47k res-->SPEED pot lug 3 and LUG 1&2-->ground.
I'd erase that jumper to ground...

Also...You didn't write that the last track is for ground too, so it should be connected to the other ground track - maybe it's the same long jumper that doesn't go the the track labelled "l" but to the last labelled "o"
O well spotted on the ground issue...that jumper wont work cause of that trace.
Title: vero
Post by: Renegadrian on September 15, 2008, 06:39:33 PM
I'm workin' on your layout, could be posting in some hours a modified version... :icon_wink:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 15, 2008, 06:41:10 PM
Nice...I think my version is pretty decent, just some jumpers are long and the connection between the two boards is a bit akward.
Title: Vibracaster
Post by: Renegadrian on September 15, 2008, 07:13:59 PM
Check this out...
(http://img291.imageshack.us/img291/3228/vibracasterrenegadrianfn2.th.gif) (http://img291.imageshack.us/my.php?image=vibracasterrenegadrianfn2.gif)



EDIT
Forgot to write that both Speed 1 and 2 go to ground
Corrected
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 15, 2008, 07:19:52 PM
Looks good! Thats one hell of a ground jumper though. ;D
Title: Re: Vibracaster
Post by: kurtlives on September 16, 2008, 05:54:29 PM
Check this out...
(http://img291.imageshack.us/img291/3228/vibracasterrenegadrianfn2.th.gif) (http://img291.imageshack.us/my.php?image=vibracasterrenegadrianfn2.gif)



EDIT
Forgot to write that both Speed 1 and 2 go to ground
Corrected
Did a careful look over and cant find any errors. I am going to building this in the next few weeks. I am building it so the osicallor can be switched on and off for a "distorsion" pedal with switchable tremolo. Should be pretty easy this way to tell if we made an error with the oscialltor layout.

You going to build one?
Title: .
Post by: Renegadrian on September 16, 2008, 06:41:19 PM
As I wrote in the page before,I am lacking some components, so I cannot build that before a couple of weeks...
But yeah that's my will...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on September 20, 2008, 01:29:39 AM
pardon me asking, but i am kinda new to building stompboxes and am having lots of trouble with power supplies.
would you just run this at 12v to the v+? or would you have to run the heaters and the v+ seperate, i just really need help as this is my biggest setback with building anything
Title: Vibracaster
Post by: Renegadrian on September 20, 2008, 05:20:52 AM
Br4d13y, if you look closely the vero layout or the schem, you see that the 12V goes to the heaters too, as the tube used is a 12AU7 - so yes it runs on 12V!  :icon_wink:
So pin 5 is wired to the +V and pin 4 to ground. No need for separate power supplies here...Easy, uh?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 20, 2008, 10:49:52 AM
Could run the pedal at 18V (Maybe higher I imagine) as long as the heaters get 12.6V DC.


My Caster is almost all drilled. Just need to finish it then wire it up.
Title: Re: Vibracaster
Post by: Br4d13y on September 20, 2008, 11:38:17 AM
Br4d13y, if you look closely the vero layout or the schem, you see that the 12V goes to the heaters too, as the tube used is a 12AU7 - so yes it runs on 12V!  :icon_wink:
So pin 5 is wired to the +V and pin 4 to ground. No need for separate power supplies here...Easy, uh?

but what if i am using the 6111? do i just have to put a resistor inbetween pin 5 and the v+?
Title: Re: Vibracaster
Post by: frequencycentral on September 20, 2008, 11:47:44 AM
Br4d13y, if you look closely the vero layout or the schem, you see that the 12V goes to the heaters too, as the tube used is a 12AU7 - so yes it runs on 12V!  :icon_wink:
So pin 5 is wired to the +V and pin 4 to ground. No need for separate power supplies here...Easy, uh?

but what if i am using the 6111? do i just have to put a resistor inbetween pin 5 and the v+?

I used a 6111 in my build. My power supply is 12 volts. The 19 ohm / 3 watt resistor in the 6111 Vibracaster schematic drops the voltage to 6.3 volts. It should be placed in series with the heater.

Note that the heater for the 6111 is pin 3 (+ve) and pin 6 (earth).

(http://i210.photobucket.com/albums/bb292/frequencycentral/6111power.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on September 20, 2008, 11:53:46 AM
thanks, i have come to understand most aspects of schematics, but power supplies always get me when it comes to tubes. also, kinda off topic, if you want to put two pedals in one enclosure, would you just wire the power in series? i really wanna make a two stage valve caster, but don't know how to connect the power
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 20, 2008, 12:04:08 PM
Youd want to power the effects in parallel. That way if one fails the other can keep chuggin.

Also if they were in series there would be a voltage drop across the first load and your second effect wouldnt be getting as much "juice".
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 20, 2008, 12:06:18 PM
thanks, i have come to understand most aspects of schematics, but power supplies always get me when it comes to tubes. also, kinda off topic, if you want to put two pedals in one enclosure, would you just wire the power in series? i really wanna make a two stage valve caster, but don't know how to connect the power

Have a look at the Twincaster schematic on the 'Tube boost + overdrive running off a 9 volt battery' thread, there's also a layout for it in Renegadrian's gallery. You would be wiring the power in parallel. Except if your'e using two 6111 tubes to make it, then you would run the two heaters in series (see diagam above), but everything else in parallel.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: SirElwood on September 20, 2008, 05:38:51 PM
Ok, even I got interested about this one. So, I build it. I used 6111 submini tube (man that's great little lamp!). First, I build a "standard" subcaster with ~20V B+. It's really good sounding preamp/clean booster. Then I add that oscillator and did changes according to frequencycentrals schematic. It works just like tremolo in my Fender vibro champ. And that's not all good thing. First of all, depth (intensity like big F calls it) sucks out alot of tone (highs) and gain. In vibro champ, you can compensate it little with treble pot. But in this case, you can't (in fact, subcaster lacks highs to begin with). And 100k reverse audio pot might work better as a depth. I also have some ticking (just like vibro champ), but I think this can be solved by good grounding. I also did that rate led modification, but it (led) was really dim, and useless. But I don't care those things anyway. :P

I don't have BC547C transistors, but it works fine with BC547B, BC548C, 2N5088 etc. I also run it with 9, 12 and 20 volts. No big difference. Anyway, speed range is good. Slow enough, but at max. even too fast (for me). It also has a kind of strong feeling in it (depth almost full). I like it alot! Only really annoying thing is that "tone sucking", because I know I have a good sounding preamp somewhere under there. Need to solve this one. It would be so cool to have tremolo and clean boost/preamp in same box. In fact, EA tremolo does this... But I'm a tube brain. ;D

So, there's my 0.02$. Great work mr. frequencycentral!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 21, 2008, 05:51:43 AM
Hey SirElwood,

Thanks for the build report. Glad you like it. And excellent that you tried different transistors too. I haven't noticed any loss of highs with my build, or on the breadboard. I agree with you about a slight loss of gain though - but I compensated for that in my build by increasing the second triodes plate resistor to 220K. I built mine as a tremolo only though - no gain or volume controls, so the increase in that resistor gave me unity between effected and bypassed. Ticking is always an issue with this type of circuit - I found that the 1N4148 got it down to a level where it was almost imperceptible though.

It's possible to play about with the cap values in the oscillator to alter the range. They don't all have to be the same value. If they were all 1uf the range would be slower. I think it would be possible to have a broader range by experimenting with a few different value caps in different positions - but the PSO is a balancing act between resistor and cap values. As R.G. said "The only thing that the circuit really cares about is that the total phase shift from the collector back to the base is 180 degrees. Any combinations that do that will work. "not working" usually results when the resistor gets too big to make up enough phase shift or so small that it pulls the feedback signal too low to sustain oscillation. Making caps non-identical works, and might offset non-identicalities in the resistors."

As for the rate LED, I didn't use that in the end either. That mod was the only way I could get around the rate LED causing ticking as it turned on and off, and I guess it's still not the perfect solution. But as I said in page 1 of this thread - "You also have to bear in mind that I'm really a complete idiot masquerading as an elecronics engineer." I take this stuff as far as my knowledge allows - it's up to others to impove on it!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: SirElwood on September 21, 2008, 06:36:29 PM
More tweaking done. I'm too tired to draw my own schematic, so I edited frequency's original (it's past 1.00AM here...). I will draw my own eventually.

Shortly:

I added 2ĶF NP cap on dwell pot, that seems to work with that gain loss. I'm not sure it's good fix, but at least it's a first step towards right direction. Then I need to bypass tremolo without true bypass. Schematic shows where I put that switch (jumper wire). I'm not sure about this either, but it seems to stop oscillator with no defects. But all this might have been on this thread earlier.

I also put a simple jfet booster in front of this. And as a gain pot a dual 100kB controls jfet boost and first cathode of 6111. I must say I think this was (is) a clever trick. Volume difference is quite big when gain is turned, but this indeed gives sweet clean tremolo and (with oscillator stopped) some nice overdrive tones. 3PDT switch to bypass this whole thing, and another 3PDT to change from tremolo to booster/overdriver. And because tremolo switch is just single on/off, I have two switchs free for something... This is not over yet! :D

Anyway... schem looks like this:
(http://www.tg-music.com/images/Vibracaster6111V2Elwoodmods1.jpg)

Quote
"You also have to bear in mind that I'm really a complete idiot masquerading as an elecronics engineer."

Same here! Random tinkering is the path to success. ;D
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 21, 2008, 06:54:25 PM
Hi SirElwood,

Glad your tinkering! I'll have to try that 2uf NP cap idea.

Probably the easiest way to bypass the tremolo function would be to have a switch to short pin 5 to earth.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: SirElwood on September 21, 2008, 07:21:19 PM
Probably the easiest way to bypass the tremolo function would be to have a switch to short pin 5 to earth.

Yes, but this way there is no change in sound. If you short pin 5. to ground, it would make some change in sound, because of that depth pot affects it. And if I remember correctly (from yesterday), that little ticking noise remained if I didin't stop the whole oscillator.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 21, 2008, 07:25:41 PM


Quote from: SirElwood on September 21, 2008, 10:21:19 AM (https://www.diystompboxes.com/smfforum/index.php?topic=70160.msg571278#msg571278)<blockquote>

Quote from: frequencycentral on September 21, 2008, 09:54:25 AM (https://www.diystompboxes.com/smfforum/index.php?topic=70160.msg571272#msg571272)<blockquote>Probably the easiest way to bypass the tremolo function would be to have a switch to short pin 5 to earth.
</blockquote>


<removed by request></blockquote>


Ok, then switch between the oscillator and earth. If you're still getting ticking without the oscillator connected to the cathode it's a decoupling issue. Put a 10uf cap across the supply rails
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 21, 2008, 08:52:42 PM
Wouldn't breaking the connection from pin 5 to the oscillator be the easiest way? That's how I was going to go about it.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on September 22, 2008, 01:55:14 AM
could someone post a schematic with all the valvecaster controls, and a boost/tremolo switch?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on September 22, 2008, 03:34:19 AM
OK, has anyone else had a go at building a 12au7 version?

I've built the version without the rate LED, and I'm not getting a lot  happening. The Valvecaster 'donor' was a working ptp 12au7; the gain and volume pots were moved and replaced with 100K resistors; the tone pot and cap was removed. It was retested again prior to the Vibe graft.

The additional circuit has been wired up on a bit of perf according to the v2 au7 schematic earlier it the thread.

I have powered it with regulated 15v, 12v and 9v. I have tried BC547, 2n5088 and 5089, and 2n3904 in the circuit.

When switched in, there is no effect, just the clean and much-loved valvecaster tone.

Interestingly enough, despite swapping the pots over 3 times for new and checked pots, there is a rumble when the depth pot is moved.

I have removed the 4148, and while I understand that was there for the LED, there is no evidence of any LFO ticking.

I'm pulling power off pin 5 and ground to pin 4. I am getting good voltage at the board. I have split the power off to its own supply with no change.

Here is my rough perf layout.

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=36698&g2_serialNumber=2)

Any thoughts? Anything obvious?

DD.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 22, 2008, 04:45:42 AM
Sounds like the PSO may not be running. I'm at work now, but later I will suggest a few tests!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 22, 2008, 09:45:06 AM
I don't think your issue is with Rick's circuit it is probably an error on your part.

Without having the time to check your layout...are you sure it is correct and you have oriented the transistors properly?

R5 should have nothing to do with Q2 in your layout.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on September 22, 2008, 10:09:45 AM
I don't think your issue is with Rick's circuit

I didn't say it was... Rick's done a great job, but I can't see any references to anyone else making the AU7 circuit. I'm looking for ideas. I'm very aware that I've probably made a stupid mistake- I normally do when the voltage is low like this!  ;D


Without having the time to check your layout...are you sure it is correct and you have oriented the transistors properly?

As you can see from my layout, I acknowledge that the 547 are 'reversed' to the 5088/9 etc. And it's the first thing I check (voice of experience...   :) )

R5 should have nothing to do with Q2 in your layout.

R5 goes across C & B of Q1; Q1's C goes to Q2's B. Therefore R5 'touches' Q2. Pardon me if I've got me B & C mixed up- it's 00:12 here... ;)

Good input tho- Cheers!

(I still reckon I've overlooked something obvious!)

DD
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 22, 2008, 10:46:58 AM
I can't see any references to anyone else making the AU7 circuit.

I'm basing my assumption that it will work identically with a 6111 or 12AU7 on the fact that I breadboard my first tremolo, Bipolar Disorder,  using a 6111 but built it using a 12AU7. For a while until I disassembled the breadboarded version I had two, one 6111 and the other 12AU7. So from that experience I'm 99.9% convinced that anything that works with a 6111 will also work with a 12AU7.

I guess the thing to do here if for you to post some voltages, specifically from the PSO part of the circuit. We'll compare them with mine and find the fault. By the way - the three caps in your PSO are NP right?

Rick
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on September 23, 2008, 12:57:54 AM
Hey, Rick.

I can't see any references to anyone else making the AU7 circuit.

I'm basing my assumption that it will work identically with a 6111 or 12AU7 on the fact that I breadboard my first tremolo, Bipolar Disorder,  using a 6111 but built it using a 12AU7. For a while until I disassembled the breadboarded version I had two, one 6111 and the other 12AU7. So from that experience I'm 99.9% convinced that anything that works with a 6111 will also work with a 12AU7.

Fair enough- and it's been great work you've done! All I'm hoping to do is help out- I've got boxes of 12a*7s but no 6111s about...  :D


I guess the thing to do here if for you to post some voltages, specifically from the PSO part of the circuit. We'll compare them with mine and find the fault. By the way - the three caps in your PSO are NP right?

Rick

The caps are 474 MKT. Resistors are .5W 1%. I've just run a scalpel around the perfboard to make sure there's no bridges.

Voltages with 5088s:

Ref voltage, 18V using a 317T down to 11,9 V.

That voltage across pins 4 & 5, and across 9V/GND on the board.

Q1 :
C  11,1V
B  11,2V
E  11,7V

Q2
C  11,7V
B  11,6V
E  11,1V

(  ???  :icon_confused: hmmm...)

Out if interest, V at lug 2 of depth is 10,6.

Turning the rate down and listening closely, it may be that the effect is running too quickly (However, I wouldn't rule out wishful thinking or the power of suggestion.) I don't have a scope here.

I may go off to the breadboard and knock up one with the LED to see if there is any action happening... Any other directions I can check out?

Cheers, DD
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 23, 2008, 02:11:23 AM
Definately a short somewhere - the emitter of Q1 connects to earth, so it shouldn't read 11.7v.

You need to have a poke about.........

I can't post readings until the other end of the day. I'll also give you a quick way to connect a temporary rate LED just for a visual sign of life.

Later!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Jimmy-H on September 23, 2008, 12:46:10 PM
Hi There,

I don't think it's a short!
Rather a bad connection.
Because it's what you said Rick: Q1 can't be 12 volt, because it's connected to ground.
So there's a bad connection to ground.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 23, 2008, 01:02:26 PM
OK. Pretty hard to get voltages from an oscillating oscillator!

This first set were taken with the PSO oscillating, but with the depth control removed. I still have the original PSO in a little corner of my breadboard right now. The blank values are because they are changing as the PSO oscillates.

Q1

E: 0.032
B:
C:

Q2

E:
B:
C:11.92


This second set of voltages were taken with the depth pot removed and the speed pot removed to stop the oscillating. Probably more meaningful.

Q1

E: 0.032
B: 0.657
C: 5.54

Q2

E: 4.96
B: 5.53
C: 11.92

I hope this helps. I suggest you remove the speed and depth pots and check the voltages against mine, just work with the PSO part of the circuit, thats where your problem is.  All your voltages appear to suggest that you have a serious short circuit to the positive power rail somewhere.

You can get a visual check on oscillation by inserting a red LED between Q2's collector and +ve. It will flash a little weakly though. You should remove it before you complete your build, as it will cause ticking otherwise.

The way I go from breadboard-to-build is to draw a schematic which I then build from, with no reference to the breadboard, so I'm the first person to beta test and verify the schematic.

I have removed the 4148, and while I understand that was there for the LED, there is no evidence of any LFO ticking.

The 1N4148 is nothing to do with the (now defunct) rate LED circuit. I put it there to cut the PSO bleeding into the audio path.

Good luck, and please report back!

Rick
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 23, 2008, 06:26:45 PM
<blockquote><removed by request></blockquote>


You could compensate for the gain loss by using a 3pdt switch.

One pole selects the PSO or earth to the second triode's cathode.

One pole increases the plate resistor to the second triode from 100k to 220k when the tremolo is switched in. Probably better to do it the other way around though, have a 220k at the plate, and when the tremolo is switched out the plate resistor is decreased by paralleling another 220k with the one already there.

One pole for a status LED!

Hope that makes sense!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on September 23, 2008, 07:33:25 PM
I was thinking of using a DPDT.

One side selects normal trem circuit the other shunts the second triode's cathode to ground.

The other side of the switch for LED.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on September 23, 2008, 10:07:09 PM
yy! just got some vero and transistors and ordered the 6111! vibracaster you are goin' doin! :icon_lol:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on September 24, 2008, 12:47:27 AM
yy! just got some vero and transistors and ordered the 6111! vibracaster you are goin' doin! :icon_lol:

oops. forgot the "a"   i meant yay.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: SirElwood on September 24, 2008, 02:14:21 PM


<removed by request>
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on September 28, 2008, 12:04:30 AM
OK. Pretty hard to get voltages from an oscillating oscillator!

I hope this helps. I suggest you remove the speed and depth pots and check the voltages against mine, just work with the PSO part of the circuit, thats where your problem is.  All your voltages appear to suggest that you have a serious short circuit to the positive power rail somewhere.

You can get a visual check on oscillation by inserting a red LED between Q2's collector and +ve. It will flash a little weakly though. You should remove it before you complete your build, as it will cause ticking otherwise.

The way I go from breadboard-to-build is to draw a schematic which I then build from, with no reference to the breadboard, so I'm the first person to beta test and verify the schematic.

I have removed the 4148, and while I understand that was there for the LED, there is no evidence of any LFO ticking.

The 1N4148 is nothing to do with the (now defunct) rate LED circuit. I put it there to cut the PSO bleeding into the audio path.

Good luck, and please report back!

Rick


PSO bleeding would give a tick, no??? ;)

I'll get back to this later; I have to go into rehersals now for the silly season in OZ (ie Summer, beaches, parties, etc.) , so I'll be unable to do any serious soldering until the middle of February. Back to the The Tone God's Bullitt for now!

Good luck- you've done a great job on these circuits! I appreciate your work!

Cheers,

DD.

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on September 28, 2008, 06:12:03 AM
PSO bleeding would give a tick, no??? ;)

I'll get back to this later; I have to go into rehersals now for the silly season in OZ (ie Summer, beaches, parties, etc.) , so I'll be unable to do any serious soldering until the middle of February. Back to the The Tone God's Bullitt for now!

Good luck- you've done a great job on these circuits! I appreciate your work!

Cheers,

DD.


Correct, PSO bleeding would give a tick, so in you case it would be good as it would confirm the PSO is running. Shame that you have to wait so long to debug - that would do my head in! If I have an effect that need debugging I simply can't sleep until it's done!

Tone God's Bullitt was very inspirational to me re. tube tremolos.

Enjoy the beach and parties while I freeze my ass of through another British winter!  :icon_mad:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 12, 2008, 12:13:39 PM


Quote from: SirElwood on September 24, 2008, 05:14:21 A (https://www.diystompboxes.com/smfforum/index.php?topic=70160.msg571927#msg571927)<removed by request>

(http://i210.photobucket.com/albums/bb292/frequencycentral/fa40b798.jpg)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 15, 2008, 05:47:51 PM
Just finished up the boost/overdrive section of the Valvecaster and it is working perfectly. Haven't wired the oscillator in yet and tested it. Hopefully I can get to that tomorrow night. That will be the real test, see if my vero part of the oscillator is correct.

I did find that a bypass cap on the first triode's cathode (gain pot) can increase the gain quite nicely and add more "bam" all around. Might be neat to have a little toggle switch for some added gain. I used a 47mF btw, just boosts all frequencies.

Ill probably incorporate the bypass cap switching into the tremolo/overdrive switch. Probably not a good idea to have a overly distorted tremolo.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 15, 2008, 06:48:13 PM
Just finished up the boost/overdrive section of the Valvecaster and it is working perfectly. Haven't wired the oscillator in yet and tested it. Hopefully I can get to that tomorrow night. That will be the real test, see if my vero part of the oscillator is correct.

I did find that a bypass cap on the first triode's cathode (gain pot) can increase the gain quite nicely and add more "bam" all around. Might be neat to have a little toggle switch for some added gain. I used a 47mF btw, just boosts all frequencies.

Ill probably incorporate the bypass cap switching into the tremolo/overdrive switch. Probably not a good idea to have a overly distorted tremolo.

Good work Chris!

Distorted tremolo can sound great - I built my Vibracaster as a tremolo only. I've been overdriving it with my Red Star Drive set to clean boost, sounds great!

Don't forget the new cap next to the Depth control.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 15, 2008, 06:58:30 PM
Just finished up the boost/overdrive section of the Valvecaster and it is working perfectly. Haven't wired the oscillator in yet and tested it. Hopefully I can get to that tomorrow night. That will be the real test, see if my vero part of the oscillator is correct.

I did find that a bypass cap on the first triode's cathode (gain pot) can increase the gain quite nicely and add more "bam" all around. Might be neat to have a little toggle switch for some added gain. I used a 47mF btw, just boosts all frequencies.

Ill probably incorporate the bypass cap switching into the tremolo/overdrive switch. Probably not a good idea to have a overly distorted tremolo.

Good work Chris!

Distorted tremolo can sound great - I built my Vibracaster as a tremolo only. I've been overdriving it with my Red Star Drive set to clean boost, sounds great!

Don't forget the new cap next to the Depth control.
Pulled out that 3.3mF cap from my bin and put it in the enclosure to remind me ;)

Where did you learn about oscillators btw?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 15, 2008, 07:02:54 PM
Where did you learn about oscillators btw?

I've built a whole bunch for my modular synths. This one was my first PSO though, thanks go to R.G.: http://www.diystompboxes.com/smfforum/index.php?topic=70056.0
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on October 15, 2008, 07:09:26 PM
so the circuit to make it a tremolo is an oscillator. correct me if i am wrong, but can i take one stage of your "crushed glass" as an oscillator, and make an all tube version? just a thought.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 15, 2008, 07:23:00 PM
so the circuit to make it a tremolo is an oscillator. correct me if i am wrong, but can i take one stage of your "crushed glass" as an oscillator, and make an all tube version? just a thought.

No - I tried that already! Not without major modifications. Besides, the Vibracaster oscillator is a sine wave, whereas the Crushed Glass oscillators are pulse wave with roughly 25% duty cycle. Sine is the classic wave for tremolo. The Crushed Glass oscillators are not very stable really - that circuit is tube terrorism, I came across the idea while I was torturing a breadboarded Valvecaster and it made a high pitched whine. They're best suited to just making an unholy racket on their own!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on October 15, 2008, 07:36:11 PM
i was hoping for an all tube tremolo, this is pretty close though, maybe i will look into it..........
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 15, 2008, 08:36:20 PM
Tubes need too high of a voltage to get them to oscillate. I would be silly to try and do it with a stompbox.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Br4d13y on October 15, 2008, 08:45:20 PM
Tubes need too high of a voltage to get them to oscillate. I would be silly to try and do it with a stompbox.

maybe we need to find some lower voltage tubes :icon_mrgreen:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 17, 2008, 09:27:13 AM
Hi Rick or any one else who might know.
I really like the 5 knob Vibrocaster and plan to do a PCB and fit it in to a Hammond BB. (the 12AU7)
I especially like the like the idťe to have a tremolo and booster combined.
I also happen to have a couple of MAX1044 voltage boosters in stock so I thought that I could let the filament and the LFO get 12V (direct from my 12V 800 mA wallvart) and the tube 24V to give it more headroom and fatter dist when I turn the gain up. Is that a good idee and if so do I have to change any resistor values by the tube?? Im a noob to tubes in pedas.

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 17, 2008, 09:41:16 AM
Hi Rick or any one else who might know.
I really like the 5 knob Vibrocaster and plan to do a PCB and fit it in to a Hammond BB. (the 12AU7)
I especially like the like the idťe to have a tremolo and booster combined.
I also happen to have a couple of MAX1044 voltage boosters in stock so I thought that I could let the filament and the LFO get 12V (direct from my 12V 800 mA wallvart) and the tube 24V to give it more headroom and fatter dist when I turn the gain up. Is that a good idee and if so do I have to change any resistor values by the tube?? Im a noob to tubes in pedas.

//Solderman

The MAX1044 has a maximum input voltage of 10.5 volts (although I have used one at 12 volts - my bad), so a LT1054s would be a better bet. I've tried plate voltages up to about 44 volts using a MAX1044 - looks good, as at low voltages tubes tend to 'round off' the tops of waveforms. Best bet would be to breadboard it and see if your ears think it's worthwhile..... :icon_biggrin:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 17, 2008, 10:41:49 AM
Quote
Best bet would be to breadboard it and see if your ears think it's worthwhile..... 

OK, Thanks Ill do that and get back with results

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 17, 2008, 05:48:02 PM
Finished my build last night....

Has some issues though...
I wired speed (3) and depth (3) backwards at first. Though I had them reversed the pedal still works but depth controls the speed and the speed control does nothing.

When I hook the connections up properly the tremolo does not work.


Also there is a slight volume loss when switching on the tremolo...Normal?

I would really appreciate if someone could look over my vero layout.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 17, 2008, 06:57:02 PM


Quote from: kurtlives on October 17, 2008, 08:48:02 AM (https://www.diystompboxes.com/smfforum/index.php?topic=70160.msg577459#msg577459)<blockquote>Finished my build last night....

Has some issues though...
I wired speed (3) and depth (3) backwards at first. Though I had them reversed the pedal still works but depth controls the speed and the speed control does nothing.

When I hook the connections up properly the tremolo does not work.


Also there is a slight volume loss when switching on the tremolo...Normal?

I would really appreciate if someone could look over my vero layout.
</blockquote>


You're using the layout on page 4 of this thread right? Your ground jumper goes to L12, it should go to O12. That would screw up the speed control, and means the oscillator has no ground connection.

As for the volume loss:


Quote from: frequencycentral on September 23, 2008, 09:26:45 AM (https://www.diystompboxes.com/smfforum/index.php?topic=70160.msg571747#msg571747)<blockquote>


</blockquote>

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 17, 2008, 10:02:12 PM
I am using the layout on pg 5 that Adriano and myself collaborated on.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 18, 2008, 02:32:39 AM
Quote
i was hoping for an all tube tremolo, this is pretty close though, maybe i will look into it..........

 
Quote
Tubes need too high of a voltage to get them to oscillate. I would be silly to try and do it with a stompbox.

 
Hi
Here is one that made just that.
From the text of the ReadHead I assume the power circut are fairly the same for the Tremler.


The Swedish "Gooobliguugyy" meas:

"TREMLER
Tremler is a Tremolo/Boost pedal. loaded with two  6021:or
Its based on the Fenders Vibro-Champ. Currently running at about : 2.5-6Hz in tremolo."

From the Redhead
".. It is powered by an external 12VDC adapter, internal boosted to 165VDC.
There is no semiconductors in the signal path.
mind you, this is not a NanoHead clone."

in my opinion those are nice builds

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 18, 2008, 02:34:36 AM
Sorry
Forgot to add the link. here it is

http://www.zeta-sound.se/tube.html (http://www.zeta-sound.se/tube.html)

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 18, 2008, 05:59:35 AM
I am using the layout on pg 5 that Adriano and myself collaborated on.

Ok I'll look over it later in more detail, but it looked good on first glance and very similar to your layout on page 4 which I checked in detail. So you should check your build for wiring errors and solder bridges. Also post you voltages for the oscillator, mine are on page 6 - you need to stop the oscillator as I did by removing the speed and depth pot to get meaningful static voltages.


EDIT: While messing around and debugging it is possible that the oscillator will stop if not wired up correctly, to make it start again turn the power off and then on again.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on October 18, 2008, 11:16:18 PM
PSO bleeding would give a tick, no??? ;)

I'll get back to this later; I have to go into rehersals now for the silly season in OZ (ie Summer, beaches, parties, etc.) , so I'll be unable to do any serious soldering until the middle of February. Back to the The Tone God's Bullitt for now!

Good luck- you've done a great job on these circuits! I appreciate your work!

Cheers,

DD.


Correct, PSO bleeding would give a tick, so in you case it would be good as it would confirm the PSO is running. Shame that you have to wait so long to debug - that would do my head in! If I have an effect that need debugging I simply can't sleep until it's done!

...

Enjoy the beach and parties while I freeze my ass of through another British winter!  :icon_mad:


Firstly, if having to wait to do a debugging does your head in, you need a hobby. Like a Frankenstrat, for example!  ;D ;D

WeI had a day off ( :o ) and I debugged it in about the same time as it takes to change a pot.

I just went with intuition, and one pot was only letting through 100K no matter what I did. When I opened it up afterwards, there was lots of little bits inside, and I'd say the wiper was dragging debris as it was turned. What did you say about being at zero degrees turn and being a straight valvecaster??

Change the pot- instant trem. I would like a level pot in there to balance it in my rig, so I'll go back and fiddle the valvecaster basics. But good job!

Interestingly, I saw the new schem version, and without the diode or electro, I didn't get any audible ticking. I'd suggest that people try without these two components, and if they need them, they know where to put them.

But that has to wait- there are beach, sun and good times to be had!

(Where abouts are you based in the UK? I know a band (http://profile.myspace.com/index.cfm?fuseaction=user.viewprofile&friendid=305954304) in the Middlesborough (http://orangeunsignedact.co.uk/acts/this-city-romance) area, and the lead guitarist is uses my pedals. You may have to be quick to see them- from what I've heard they're on the verge of killing the egotist vocalist. The vocalist doesn't write the songs, but he's keeping the fees...)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 19, 2008, 07:54:34 AM
Good news Diamond Dog! Debugging often seems to be really simple things. Interesting that you didn't use the diode or cap to prevent ticking, I did find before my 'fix' that it was noticable with some amps but not with others, and also depended on what other pedals were before it and after it. Check it at HIGH volume. Maybe I'm just being precious, but I had to find a fix that prevented it ticking under ANY circumstances.

I'm in Coventry, UK - Middlesborough is a long way away - and then there's the language barrier too!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 19, 2008, 03:22:08 PM
Hi and thanks all for the good info on this one (especially Rick who has design it)
After about 20+ projects I was beginning to wonder what type of project I should do next. Yet another distbox did not feel all that inspiring. Then I found this one and now I am really keen to build it. To do so I have made a DIY project file to etch a PCB. It is not verified yet so If someone spots an error, please yell.  (I only use PCB in my builds. I sort of fail every time I tried veroboard and such.) Since I have set out to only use Hammond 1590B for the big ones and then with the audio and power jacks on the top short side, to save pedal board space, I have made a PCB layout made to mount both the put:s and the tube socket on the PCD. I omitted the Tone put for space reasons and the Trem/OD switch but the 3,3uF cap is in. I happened to have a few MAX1044 in stock so I though that I use one to feed the tube plate side with 24V. I know the MAX1044 only suppose to be feed 10,5V max but 12V has been known to work so I have heard. There is actually two PCB:s. The second one is for the audio and power jacks but I am waiting for the PCB mounted power jacks Iív ordered so I have nothing to take accurate measurements from so and cant finish that boar yet. Iíll post it as soon as I get the jacks.  So tomorrow Iím off to my local tube pusher to by me some 12AU7:s. As soon as it is ready (1-2 veeks) Ill post sound samples and info on my site.

Next step, when I find some where to buy 6111 and other subminis, I will try to shrink a Valvecaster to fit in to a Hammond 1590A.

Here is the project file and a pic of how I was thinking to assemble it all. I also submitted a link to the DIY file if anyone should care to use this as it is the only way I have found to print an accurate sized transfer to PCB from the DIY layout software and to show all the component values. (Some are missing on the pic)


(http://solderman.fatabur.se/Future%20project/Vibra_project.jpg)

How i am planing to mount it
(http://solderman.fatabur.se/Future%20project/Vibra_box.jpg)

DIY file
http://solderman.fatabur.se/Future%20project/VibraCaster.diy (http://solderman.fatabur.se/Future%20project/VibraCaster.diy)


//Solderman 
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 19, 2008, 06:49:54 PM
That looks like a great piece of work solderman! One thing that occurs to me is that the circuit might operate differently with 24 volts to the plate and 12 volts to the oscillator, I'm not sure but I think the tremolo might not be as strong - I highly recommend you breadboard it before implementing it. The other alternative is the give the oscillator the same voltage as the plate - you would have to check the BC547C data sheet for its maximum voltage. With MAX1044 running at 12 volts, the output voltage will be about 22.6 volts, as each 1n4148 eats 0.7 volts. Be warned though - R.G. Keen castigated me for running MAX1044 above it's maximum operating voltage! It might run fine for a while then fail..........it might be fine, but it's not good engineering practice. You might be better to run the whole thing at 9 volts with the MAX1044, then use a few doubling stages from there. Good luck and post your results!

Rick
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 20, 2008, 01:06:08 AM
Thanks Rick
Thanks for the tip about 24V to the tremolo. Ill will test both with and without 24V to the BC547:s and check there limitations before soldering it down. Yes I know about the issue with MAX1044 and 12V not being good or best practice but Ill take my chances. 9V idťe was something I havenít thought about. It would be in the range for the MAX1044 and yet raise the plait voltage a bit. It would give the plate around 17V and the BC547 9V.The fillment will drop to 9V though witch might be too low. The jumper in the charge pump is actually meant as a wire jumper, easy to put in or remove. If the charge pump wont work Ill just trough in the jumper and pull out the IC. I thought it would be more flexible this way. I can also see that I made a goof in the choice of components. The MAX1044 datasheet actually recommends fast schottky diodes like BAT85 (30V 200mA) instead of 1N4001. As soon as I have something working (or maybe not) Ill post the results.

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 20, 2008, 05:36:24 AM
You can use a number of diode/cap stages to get much higher voltages using the MAX1044, have a look in 'Circuit Sweepings' over at Geofex.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 22, 2008, 11:03:42 AM
Hi
I have just finished the VibraCaster.

The Drive part works grate but it wont oscillate.

I have built it on this PCB

(http://solderman.fatabur.se/Future%20project/Vibra_project.jpg)

Q1 (the one surownded by R7 3M3)
E=0
B=0.58
C=7.95

Q
E=11,76
B=7.91
C=7,29

At lug 3 of Depth=3.55 not moving


I have used the BC457B

Anny suggestions ???

//Solderman

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 22, 2008, 01:02:42 PM

Q1 (the one surownded by R7 3M3)
E=0
B=0.58
C=7.95

Q
E=11,76
B=7.91
C=7,29


This set of voltages were taken with the depth pot removed and the speed pot removed to stop the oscillating. With the oscillator running it's impossible to take volatges, as they are changing all the time!

Q1

E: 0.032
B: 0.657
C: 5.54

Q2

E: 4.96
B: 5.53
C: 11.92

I hope this helps. I suggest you remove the speed and depth pots and check the voltages against mine, just work with the PSO part of the circuit, thats where your problem is. 

Comparing your voltages with mine, it looks like all the Q2 voltages are well off, so thats the palce to start. Is the transistor correctly oriented? You Used BC547B, these are lower gain than BC547C, that might be enough for the oscillator to be too underpowered to start
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 22, 2008, 06:10:09 PM
Hi Again

No, I did not get the tremolo part to fire up. I guess its because off the to low gain BC547B transistors that I have used. But Iím off to by C:s tomorrow so I will find out if that fixes the tremolo part. But I couldnít just sitting there doing nothing just because all the shops were closed and I have to wait until tomorrow so I poked around and used what I hade in stock and this is the result. Itís a trem section much alike the original but a bit simpler and with a rate LED. Itís a mix of EH tremolo LFO section and this one.

Here is the Schematics (R3 is 15K and i also used BC547B witch i found a bit smother but that could be juat me)
(http://solderman.fatabur.se/Future%20project/Vibra.jpg)



Here is a sound sample of me abusing a Stratocaster and playing with the depth, speed and gain pot.

http://solderman.fatabur.se/Future%20project/Vibracaster.mp3 (http://solderman.fatabur.se/Future%20project/Vibracaster.mp3)

Hers a pic of the test rig.

(http://solderman.fatabur.se/Future%20project/VibraCaster_test.jpg)

//Solderman     
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on October 23, 2008, 08:35:23 AM
Good news Diamond Dog!
..
Check it at HIGH volume. Maybe I'm just being precious, but I had to find a fix that prevented it ticking under ANY circumstances.

What? You want me to check it at HIGH volume- through two Blackface modded Twin Reverbs???

OK!   ;D ;D ;D

I'll throw the diode and cap back in when I'm at home again... There's no harm covering as many bases as possible. Like a bulldozer chasing butterflies.

Again- good job! Love your work!
Title: Vibracaster
Post by: Renegadrian on October 23, 2008, 08:42:47 AM
Solderman, I like your last experiment...Did you try it on vero too?  :icon_wink:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on October 23, 2008, 10:21:32 AM
Good news Diamond Dog!
..
Check it at HIGH volume. Maybe I'm just being precious, but I had to find a fix that prevented it ticking under ANY circumstances.

What? You want me to check it at HIGH volume- through two Blackface modded Twin Reverbs???

OK!   ;D ;D ;D

I'll throw the diode and cap back in when I'm at home again... There's no harm covering as many bases as possible.

Again- good job! Love your work!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 23, 2008, 01:24:25 PM
Hi

Quote
Solderman, I like your last experiment...Did you try it on vero too? 

No, But if you download the DIY file and open it in  DIY layout Creator (the old one)  you will probably be able to fix one in a wink.

OK, being a newbe to tubes means making misstakes. The first I made was to assume the pinout of the tube went clockwise WRONG.  >:( OK, only to redraw and etch a new board.  Then the Trem woldent fire up.  ??? After a lot of tweeking and hassling with it I finlay bought new trannis and I change to BC547C in stead of B. That did nothing.  :(  Then I changed the whole layout for the LFO on the PCB to the one on my schematick. Thath one one did NOT work ether on the PCB even though it worked perfectly on the test board.  :(  After thingking looking and thinking again and looking with my absolutely strongest magnifying galss I found a bit of trace that was not connecting between to caps. it was about .05 mm but enough to fool me. The original LFO would probably have worked if i had spotted this earlier. But now it works and sounds good. here is some of my findings. I have tryed with both BC547B and C in this LFO and both works.





The pics and links I have posted earlear are updated but I post them again just to be sure that no one uses the ones that dos not work.

(http://solderman.fatabur.se/Future%20project/Vibra_project.jpg)

(http://solderman.fatabur.se/Future%20project/Vibra.jpg)

http://solderman.fatabur.se/Future%20project/VibraCaster.diy (http://solderman.fatabur.se/Future%20project/VibraCaster.diy)


//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 23, 2008, 02:07:01 PM
Hey, really glad you got it running solderman, I get a real bad sense of culpability when someone builds one of my designs and it doesn't work first time - even though I have built it from the same schematic a couple of times! I have to get over that - I lost some sleep for you!

Your PCB looks ACE by the way, and I really enjoyed your soundclip - can't wait to see the finished pedal too.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on October 23, 2008, 02:22:30 PM
(http://solderman.fatabur.se/Future%20project/Vibra.jpg)

Anders, for what i understood this one is not what you put in the biggest layout? but you tried it and it works, as for the soundclip...So yep I'd like to turn it into a vero layout. Gonna do it in the next days, so I wondered if you did it already...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 23, 2008, 03:47:12 PM
Quote
Anders, for what i understood this one is not what you put in the biggest layout? but you tried it and it works, as for the soundclip...So yep I'd like to turn it into a vero layout. Gonna do it in the next days, so I wondered if you did it already...


Well It actualy is the same LFO circut if you look at the layout and the schematic you can se that.

On the layout C6,7 and 8 are C1,2,3 om the scematic

C4=C9
R1=R8
R2=R7
R3=R5
R4=R6
R5=R9

Cant remember If I updated the DYI file but Ill check thate later.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 25, 2008, 09:37:52 PM
Can someone look over the layout at the TOP of PG 5 please?

I wired the speed and depth pots backwards and it works. Well works in the sense that depth adjusts speed. And the speed control does nothing.

If I switch them around to their proper positions I get no trem effect.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 26, 2008, 01:34:51 AM
Quote
Can someone look over the layout at the TOP of PG 5 please?

I wired the speed and depth pots backwards and it works. Well works in the sense that depth adjusts speed. And the speed control does nothing.

If I switch them around to their proper positions I get no trem effect.

Hi Chris

I have looked over the layout and as far as I can see, everything checks out. A way for you to trouble shoot it would be to replace the 1N4148 with a LED, oriented as the 1N4148 and connect the anode to +12V instead of pin 8. If I have understood the circuit it supposes to lower the potential at lug two on the depth pot to GND in a sine wave. This will mean that the LED will flash when/if everything is OK.

So, do the Ursula's, look for solder bridges etc. As you can see from my post above I spent hours to find a tiny trace cut that I accidentally made drilling a hole to correct a layout error I made in my first layout.

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 26, 2008, 06:39:04 AM
@ kurtlives - I checked your layout too, it looks good to me, so the fault must lie elsewhere - maybe a solder bridge as solderman says, or a wiring error. Stop the oscillator by removing the speed and depth controls then post your voltages for Q1 and Q2.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 27, 2008, 12:49:17 PM
Hi
Iím proudly introducing Mr U-tube.

Credit to Rick who started this thred about a valve tremolo.
This is my result. Now it is boxed and Iím quit happy whit the result it sounds good to my ears. The wooden line is a washer to make up for the distance needed inside. 30 mm wasnít enough to host the tube socket and the jacks upon each other.

(http://solderman.fatabur.se/Future%20project/U1.jpg)
(http://solderman.fatabur.se/Future%20project/U2.jpg)
(http://solderman.fatabur.se/Future%20project/U3.jpg)


//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 27, 2008, 01:28:25 PM
Wow that's a tight fit! No wonder you neded the washer - I love the U tubes! I've got a couple of those nice knobs in black for my mojo FF build. Now - soundclips and gutshots please!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on October 27, 2008, 04:19:08 PM
Hi
OK, a gutshot wouldent be anything to se caus its only the backside of the PCB. but here is the content of the box. Everyting is on the PCB exept the jacks that have there one. The yellow and purpel cables are of caus hooked ut to the stompswitch in the box togeter with the LED.

(http://solderman.fatabur.se/Future%20project/U4.jpg)

Sound sample
http://solderman.fatabur.se/Future%20project/Vibracaster.mp3 (http://solderman.fatabur.se/Future%20project/Vibracaster.mp3)

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 29, 2008, 04:18:12 PM
Rick I got some voltages with the pots disconnected...

Q1
C - 7.79V
B - 0.63V
E - 0V

Q2
C - 14.23V
B - 7.77V
E - 7.19V

They actually seem quite good dont they? More or less in line...I wanna check Q1's emmiter area though.

Any suggestions?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 29, 2008, 05:14:34 PM
Rick I got some voltages with the pots disconnected...

Q1
C - 7.79V
B - 0.63V
E - 0V

Q2
C - 14.23V
B - 7.77V
E - 7.19V

They actually seem quite good dont they? More or less in line...I wanna check Q1's emmiter area though.

Any suggestions?

Yes, they look pretty close. Your Q2 collector is 14.23V - is your DC just very slightly above that? My voltages were taken with DC of 11.94 volts.

Frustrating! There is nothing really obvious from your voltages. But yes, Q1's emmiter looks a bit suspect, and I would expect it's base to be higher too.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on October 29, 2008, 05:48:30 PM
For the time being everything is wired a bit loose and no regulator. That's why I get the 14V.

Very frustrating indeed... My ideas....cold joint, solder bridge, bad pot. I am sure it is on of the three.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 29, 2008, 06:19:30 PM
For the time being everything is wired a bit loose and no regulator. That's why I get the 14V.

Very frustrating indeed... My ideas....cold joint, solder bridge, bad pot. I am sure it is on of the three.

I'm assuming the oscillator will work on 14 volts, but I have no way the check. Maybe it's enough to knock everything out.

Good luck!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on November 09, 2008, 05:59:57 PM
Found my problem! DC current getting into the oscillator. The problem was obvious and the fix was simple ;)

This weekend was a tube weekend. Finished my 18W (waiting on tubes to test it) and I finished this...

(http://img.photobucket.com/albums/v610/kurtlives/DSCF0264.jpg)

(http://img.photobucket.com/albums/v610/kurtlives/DSCF0267.jpg)

It sits beside it's twin the Valve Caster and looks awesome!

For comparison...
(http://img152.imageshack.us/img152/529/dscf0129bi9.jpg)

Great pedal! Thanks Rick.
Title: My Vibracaster Report
Post by: Renegadrian on December 22, 2008, 02:00:52 PM
Here I am, after a lot of "I'll do it soon" the time has finally come!!!
I dubbed it the WIRING NIGHTMARE - maybe because wiring isn't the thing I like the best...but 4 knobs, the tube socket among them, dc jack+7812 and switch...A good number of wires to solder!!!  :icon_neutral:

Anyway, it fired just right as soon as I plugged it in...Used a couple of bc548c (haven't got the 547 as the schematic).
What can I say...I think I like it!!! played with it for 30 mins, it's good as a standard Valvy (with depth at the min.) and as a tremolo, a little volume loss but not that much, and a little ticking at the min speed - but that's ok...
I like the standard sound and the tremolo with the gain at the min - not so fond with tremolo on at full gain - and yeah it has a good gain!!! I'm quite pleased about it...I think I will upload a sample soon...

Here it is with its brother...
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=38072&g2_serialNumber=1)
Title: Re: My Vibracaster Report
Post by: frequencycentral on December 22, 2008, 03:01:24 PM
WIRING NIGHTMARE
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=38072&g2_serialNumber=1)

Hahaha - they look so cool together! I wanna see WIRING NIGHTMARE gutshots!

Did you use that 3.3uf cap mod to stop ticking?

Well done Adriano anyway! Makes me proud........ :icon_smile:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on December 22, 2008, 04:52:12 PM
Why not Rick, I'll post the guts too...
I followed the layout made by Chris (kurtlives) and modified by me, but there was no 3.3 cap in that layout - I'll put one in a minute, thx for the hint!!! (http://forum.ubuntu-it.org/Smileys/xmas-smileys-new/good.gif)
Happy you liked my work...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on December 22, 2008, 05:43:42 PM
Ya I didn't include it, I just wired it right to the pot.

You can see it in my pics, pot on the far left.
Title: Vibracaster
Post by: Renegadrian on December 22, 2008, 05:49:09 PM
I still got a minor ticking but I believe it is part of the circuit....I'll post some more s..t of it anyway.
Nice circuit!!!



EDIT
Here's the tweaked layout, just some minor changes of what you see at page 5, and the 3.3ĶF cap Rick suggests to add.
q1 and q2 are oriented correctly, I tried 2n5088 with no big differences, but they go the opposite way.

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=38094&g2_serialNumber=1)

I made some samples with it...Some of the songs I think the Vibracaster suits well...
You can find them in my gallery, in this subfolder --->link (http://www.aronnelson.com/gallery/main.php/v/Renegadrian/samples/)
I will also add the intro of Gn'R "Don't cry" - I have a sound that's very close...
Title: Re: My Vibracaster Report
Post by: solderman on December 26, 2008, 03:59:33 AM
Here I am, after a lot of "I'll do it soon" the time has finally come!!!
I dubbed it the WIRING NIGHTMARE - maybe because wiring isn't the thing I like the best...but 4 knobs, the tube socket among them, dc jack+7812 and switch...A good number of wires to solder!!!  :icon_neutral:


Hi Adriano
Seriously nice boxes. I kind a like the green metallic finish. It looks as vintage as the sound one can squeeze out of this box.
I felt a shiver up my spine when I thought of all the wiring on this one when I planned my build. :-[. That's why I made mine with PCB mounted pots and tube socket (See page 8 on this thread).

Happy holidays every one  :D

//Solderman

 
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: runmikeyrun on December 26, 2008, 11:00:46 AM
If i were to implement this trem into a twincaster, would i put the wire for the trem circuit off the 2nd or 4th gain stage?  My gut tells me 2nd.
Title: Vibracaster
Post by: Renegadrian on December 26, 2008, 01:53:32 PM
Mike, I'd try to put the trem part even after the first stage...I love this Vibracaster, but the best sounds are with the gain knob at its min. - don't like the distorted sound with the tremolo on...So it could be interesting to try to put it after the first stage, or just ditch the gain pot in favour of a fixed resistance, to give a small amount of gain or none, as Rick did if I remember correctly...
So I'd say you could have a 2 or 3 switches pedal, with
-1 or 2 stages at low gain and the trem
-2 stages (standard valvecaster)
-4 stages (twincaster)

Anders, glad you liked it, yeah there's a lot of wire to solder, I spent quite a lot of time just to find the best components' positions inside the enclosure, I ended up with the tube socket in the middle and the four knobs around - sure the wiring needed some more attention, but I just don't wanna think of my wiring skills let's say 6 months ago, it would have been a spaghetticaster!!!  :icon_razz:
I'll post a couple of guts pics...

I think I am gonna build another one someday, but you know the BB size could help...

all the best and take care...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on December 27, 2008, 07:13:04 AM
If i were to implement this trem into a twincaster, would i put the wire for the trem circuit off the 2nd or 4th gain stage?  My gut tells me 2nd.

I built my Vibracaster as a clean tremolo only device, just two knobs, speed and depth. I think it sounds great with a clean guitar signal. I also think it sounds great with my Valvecaster (or Pepper Shredder, or Pentadriver, or Red Star Drive) before it - I like that distorted tremolo sound a lot.

So, if it were me, I would wire up the 4th stage as the trem in a Twincaster. It occurs to me that using the 2nd stage would 'trem the gain', but using the 4th would 'trem the volume' - if you get what I mean. It would be a slighly different effect depending on where you put it, so maybe the best option would be to make it switchable between the 2nd and 4th.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: danielzink on December 27, 2008, 11:12:49 AM
Just because I've got 3 5672's sitting around............ ;D

Did we ever get anywhere with the tube trem on 5672's ?

http://www.diystompboxes.com/smfforum/index.php?topic=71083.20


Thanks.....sorry to hijack....

Dan
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on December 27, 2008, 11:18:38 AM
Just because I've got 3 5672's sitting around............ ;D

Did we ever get anywhere with the tube trem on 5672's ?

http://www.diystompboxes.com/smfforum/index.php?topic=71083.20


Thanks.....sorry to hijack....

Dan

Believe it or not, I'm working on it right now!  :icon_cool:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on December 27, 2008, 06:45:11 PM
Rick's the man...(http://forum.ubuntu-it.org/Smileys/xmas-smileys-new/cool.gif)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 17, 2009, 03:15:53 AM
I recently did a bunch of soundclips, so here's another chance to hear my 6111 Vibracaster: http://www.aronnelson.com/DIYFiles/up/Vibracaster.mp3

Signal path:

Squier Telecaster Custom (HB)  >  Vibracaster  >  Roland Bolt 60 watt tube combo  >  Shure SM58  >  Event Echo Gina 24 soundcard  >  Wavelab

No other processing. It's a montage of a few different settings.

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 25, 2009, 07:49:28 PM
Hi
So I made the vibracaster, but it didn't work :icon_redface: LOL
Checked everything over checked the voltages........ So I started thinking what different about my vibracaster????
Oh I know it's the transistors :icon_idea: The shop did not have any of the BC547C, they only had the Bs, so I got a pair of NTE199.
NTE states they are equivalent to the BC547C. The only problem is the pin out of the NTE199 is different then the 547C Just found that out now after looking at the two data sheets.
I'll have to pull the trannies out and twist the leads put them back in and see if they still are good?

Heads up when subing out electronic components, not all manufactures use the same pinout configuration!

Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 25, 2009, 08:11:01 PM
I remember doing the same with BF245's, assuming the pinout would be the same as BF244's. And they're so numerically close too! Good luck with your debug, my voltages are posted earlier in the thread if you need them.

Rick
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on March 26, 2009, 10:59:45 AM
mmm would the 547B work?! I used Cs with mine, but Bs are so much different? Is it just a matter of hfe, right?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 26, 2009, 12:26:42 PM
mmm would the 547B work?! I used Cs with mine, but Bs are so much different? Is it just a matter of hfe, right?

Good question Adriano
I'm not sure if it would be a big difference.
I do have a pair of the 547b I'll put them on the board and try it out, but I have nothing to compare them too.

Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 26, 2009, 01:09:30 PM
mmm would the 547B work?! I used Cs with mine, but Bs are so much different? Is it just a matter of hfe, right?

I breadboarded a very similar LFO for my Vintage Vibe, BC547B will work for the second transistor, but the first (the one with the 3M3 resistor) must be a BC547C or equivalent. The B wouldn't have enough gain for oscillation to start.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 26, 2009, 10:22:51 PM
Hi
I took the trannies out and reinstalled them properly.
But it still doesn't work, nothing :icon_evil: :icon_evil:
So I desoldered the trannies out again and tested them with my meter.
They both measured out at 486Hfe so they both work.
So I guess I'll solder them back in and then check the voltages with the pots removed.

Rick
How critical is the 3.3m value?
the supplier did not have 3.3m so I got 2.7m and 3.9m The board has the 3.9m on it!

Here is the schematic I made using Eagle for the board.
I don't see anything out of place!?!?!?!?!?!

(http://i107.photobucket.com/albums/m297/biggy-boy/vibracaster.png)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 26, 2009, 11:37:51 PM
That looks like a great piece of work solderman! One thing that occurs to me is that the circuit might operate differently with 24 volts to the plate and 12 volts to the oscillator, I'm not sure but I think the tremolo might not be as strong - I highly recommend you breadboard it before implementing it. The other alternative is the give the oscillator the same voltage as the plate -
Rick

Oh no I just read this :icon_eek:
I'm running my tube plate voltage at 157 volts maybe that's why I get no oscillation. The oscillation section is fed with 12volts
I made an add on board for the osillation section and then tied it into my already made valvecaster. The valvecaster runs great at the 157 volt plate voltage.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 27, 2009, 03:28:08 AM
Rick
How critical is the 3.3m value?
the supplier did not have 3.3m so I got 2.7m and 3.9m The board has the 3.9m on it!

The PSO is a juggling act between values. If you change one you will need to change others to compensate. Have you got a 680K you could put in series with the 2M7 to get 3M3.8? Or you could parallel a 2M7 with a 3M9 to get 1M6, do do this twice, put you two 1M6 in parallel and you have 3M4.

Your schematic looks fine.

One thing that occurs to me is that the circuit might operate differently with 24 volts to the plate and 12 volts to the oscillator, I'm not sure but I think the tremolo might not be as strong

This is a guess - I may be wrong on this.

I'm running my tube plate voltage at 157 volts maybe that's why I get no oscillation. The oscillation section is fed with 12volts
I made an add on board for the osillation section and then tied it into my already made valvecaster. The valvecaster runs great at the 157 volt plate voltage.

You need to assure yourself the oscillator is working correctly first, you should be able to hook up a LED to the output as a visual check that it's running. This is mentioned earlier in the thread somewhere. Once you know the oscillator is working you can apply it to your circuit. If the tremolo is weak you may need to consider lowering the plate voltage.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 27, 2009, 10:26:38 AM

  Have you got a 680K you could put in series with the 2M7 to get 3M3.8? 
Your schematic looks fine.

 
 

OK thanks Rick

I'll go the 680k way, or go with a trim pot maybe.
 Yes its time to isolate just the isolation board and find out whats going on.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 29, 2009, 02:20:54 PM
OK found some 3.3m in the 1/2 watt section of the supplier.
Also picked up a pair of BC549C transistors, they seem to be the same hfe as the 547c, just have a lower max voltage of 45 volts instead of 60 volts.
My pcb is getting battered from soldering and unsoldering parts so may times my need to remake the board :icon_sad:
Also going to add sockets to the board to allow the swapping out of tranistors if they don't work.
I have ten of the 457C coming from ebay soon, but will try the 459C in the meen time.
one day I'm get my act together.

data sheet for the 549C
http://pdf1.alldatasheet.com/datasheet-pdf/view/16103/PHILIPS/BC549C.html

Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 29, 2009, 05:27:51 PM
OK I got to walk away from this project for a day or two. At age 46 I can't afford to loose any more hair  :icon_eek:  :icon_rolleyes:
I put in the 3.3meg resistor put in the new 549C transistors disconnected it from the tube and installed an
LED now what I have is a fabulous dimmer control for the LED!!!
Still no oscillation.

The speed pot does nothing to the LED. But the second pot the depth one makes it dim and turn off.
At one end it makes the LED very bright as I move the pot towards the other end it goes off and once its at the other end it comes back on but very dim.
I rechecked all the other resistors to make sure the values were correct and they are.

Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 29, 2009, 05:52:47 PM
Hi Glen, sorry you're having trouble getting it going, Here's some info that should help your debug from page 6 of this thread:

OK. Pretty hard to get voltages from an oscillating oscillator!

This first set were taken with the PSO oscillating, but with the depth control removed. I still have the original PSO in a little corner of my breadboard right now. The blank values are because they are changing as the PSO oscillates.

Q1

E: 0.032
B:
C:

Q2

E:
B:
C:11.92


This second set of voltages were taken with the depth pot removed and the speed pot removed to stop the oscillating. Probably more meaningful.

Q1

E: 0.032
B: 0.657
C: 5.54

Q2

E: 4.96
B: 5.53
C: 11.92

I hope this helps. I suggest you remove the speed and depth pots and check the voltages against mine, just work with the PSO part of the circuit, thats where your problem is.

You can get a visual check on oscillation by inserting a red LED between Q2's collector and +ve. It will flash a little weakly though. You should remove it before you complete your build, as it will cause ticking otherwise.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 29, 2009, 09:36:26 PM
Here's the numbers!

The applied voltage 12.20v

Both pots disconnected

Q1

E: 0V
B: .6V
C: 6.77V

Q2

E: 6.18V
B: 6.77V
C: 12.2

I put my LED that I was talking about on the end of the wire that goes to pin 8 of the tube.
I disconnected it from the tube before connecting the LED. The other end of the LED I put to 12v+
I just saw that I was supposed to connect it to the collector of Q2 not the output to the tube????

EDIT:
I just tried hooking a red LED minus side to the Q2 collector and the plus side to 12+ the led didn't do any thing .
I also hooked it up to the output wire that goes to pin 8 and it barely lights, but if I use a green led it light real bright. the green one is the one i use din my other post, not a red one. The green one doesn't work when connected to the collector.
Question am I supposed to disconnect the collector pin from the circuit before hooking the LED to it?



Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 30, 2009, 05:36:07 PM
I just can't leave this thing alone LOL ::)

OK more info
I have the oscillation board isolated, no tubes! but hooked up to the pots

12.20 volts Dc applied to the oscillator.
I measure from ground of the board to the out put that goes to pin 8 it measures minus 44 volts?  what? OK
I guess it's minus because the Q2 inverts it, but is the circuit supposed to be a doubler too?
If I measure from gnd to the base of Q2 I get a fluctuating voltage, also from the emitter to gnd the voltage fluctuates.
I take it this thing is oscillating then!?!?

I'm going to try hooking it back up to the tubes and give it a try


Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 30, 2009, 06:59:37 PM
I measure from ground of the board to the out put that goes to pin 8 it measures minus 44 volts?  what? OK
I guess it's minus because the Q2 inverts it, but is the circuit supposed to be a doubler too?

 ??? Q2 should just buffer the oscillator, no doubling, how can you have 44 volts there? You are running 45 volts into the tube right? The anode resistor should reduce this considerably though. Are you sure you didn't have your DMM the wrong way around?

If I measure from gnd to the base of Q2 I get a fluctuating voltage, also from the emitter to gnd the voltage fluctuates.
I take it this thing is oscillating then!?!?

That looks like oscillation to me!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 30, 2009, 07:17:37 PM
No I didn't have it connected to the tube circuit at all totally isolated.
LOL Retested the voltage out to pin 8 to gnd and was getting minus 44 volts but I was pinching the test lead between my thumb and finger and the wire coming off of the board that is to go to pin 8 I'm an Electrician by trade I guess all the years of being shocked by high voltage has given me super powers Like a capacitor :icon_twisted: :icon_wink:
 If I just put the test lead on the wire that is to go to pin8 I get like 7.6 volts with a very small fluctuation in voltage.

I hooked it back up to the valve caster and still no trem sound.

Rick the LED test I hook the minus side of the LED to the collector of Q2 then the positive to the plus 12volt supply? But do I have to disconnect the collector from plus 12 first?
You know put the LED in series withe the collector?

Glen




Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 30, 2009, 07:22:23 PM
I bread boarded a new setup.
I used an nte199 supposed to be the same as the bc547C for Q1 and a BC547B as Q2
I did not use pots instead I used 47K resistors in there place to simulate centering the pots.
Did not oscillate.
tried bigger and smaller resistors along with the 3.3m but nothing.
Even tried an NPN with an Hfe of over 1000 for Q1 nope!

I don't know I have 10 BC547C coming in the mail.
I guess I'll go plug my guitar into the ValveCaster crank it up and go have fun until the new trannies come in :icon_cool:

Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on March 30, 2009, 07:26:13 PM
Rick the LED test I hook the minus side of the LED to the collector of Q2 then the positive to the plus 12volt supply? But do I have to disconnect the collector from plus 12 first?
You know put the LED in series withe the collector?

Yes, put the LED between Q2's collector and +ve. I hope you get this sorted soon! It must be frustrating the hell out of you!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on March 31, 2009, 01:53:59 PM
I bread boarded a new setup.
I used an nte199 supposed to be the same as the bc547C for Q1 and a BC547B as Q2
I did not use pots instead I used 47K resistors in there place to simulate centering the pots.
Did not oscillate.
tried bigger and smaller resistors along with the 3.3m but nothing.
Even tried an NPN with an Hfe of over 1000 for Q1 nope!

I don't know I have 10 BC547C coming in the mail.
I guess I'll go plug my guitar into the ValveCaster crank it up and go have fun until the new trannies come in :icon_cool:

Glen


Hi Glen

I manage to screw up my LFO part of the layout for the wibra caster as well and thougt it was the trannies but it was me as moste of the time. No, I did not get the tremolo part to fire up. I thaught it was because off the to low gain BC547B transistors that I have used.  But I couldnít just sitting there doing nothing just because all the shops were closed and I have to wait until tomorrow so I poked around and used what I hade in stock and this is the result. Itís a trem section much alike the original but a bit simpler and with a rate LED. Itís a mix of EA tremolo LFO section and this one.

Here is the Schematics (R3 is 15K and i also used BC547B witch i found a bit smother but that could be juat me)
(http://solderman.fatabur.se/Future%20project/Vibra.jpg)

And a crapy sound sample 
http://solderman.fatabur.se/Future%20project/Vibracaster.mp3 (http://solderman.fatabur.se/Future%20project/Vibracaster.mp3)

//Solderamn

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 31, 2009, 04:52:50 PM
Solderman!

Thanks I'll give it a try tonight.
The wire that is marked go to 1N4148 I guess the other end of the diode goes to pin #8 of the tube?? as in Ricks diagram?


Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on March 31, 2009, 07:19:33 PM
OK tried soldermans circuit still doesn't oscillate just turns on the LED?
In the diagram that I attached in the circle is that a junction ( are those wire all connected at that spot?)

Also I don't have any RED LEDs I'm using blue and have tried green, does this matter??

Does this circiut need a load on the wire going to the diode mine is not connected to anything other then 12volts DC

More then six hours and still can't flash a fricking LED with a Transister WTF am I a retard or what? :icon_mrgreen:

(http://i107.photobucket.com/albums/m297/biggy-boy/vibra.jpg)


Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on April 01, 2009, 01:31:14 PM
OK tried soldermans circuit still doesn't oscillate just turns on the LED?
Check the Transistor is it correctly oriented??

In the diagram that I attached in the circle is that a junction ( are those wire all connected at that spot?)
Yes they are


Also I don't have any RED LEDs I'm using blue and have tried green, does this matter??
NO
Does this circiut need a load on the wire going to the diode mine is not connected to anything other then 12volts DC
Does not matter it runs on both 9 and 12V (http://Does not matter it runs on both 9 and 12V)

More then six hours and still can't flash a fricking LED with a Transister WTF am I a retard or what? :icon_mrgreen:

Check my layout for this LFO on page 8 I think Its verified and OK eaven if its PCB you can use it for Vero or Perf. But I think the easiest is to do a dead bug

//Solderman




Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: TotemTek on April 02, 2009, 01:55:20 PM
hu guys!

i built this circuit today. i built it exactly the same as rick's version 3 design on page 6, with all the same component values and everything.

the only thing i don't quite understand is how to power it. do i put all of the V+ points of the circuit to a single 12v dc source? my bypass is working but when i engage the pedal i get nothing!  :D

i'm guessing it's a simple fix, either a bad joint, incorrect V+ wiring or the wrong kind of capacitor used. I will look into incorrect capacitor type once i've ruled out the previous two speculations.

thanks
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 02, 2009, 04:27:48 PM
hu guys!

i built this circuit today. i built it exactly the same as rick's version 3 design on page 6, with all the same component values and everything.

the only thing i don't quite understand is how to power it. do i put all of the V+ points of the circuit to a single 12v dc source? my bypass is working but when i engage the pedal i get nothing!  :D

i'm guessing it's a simple fix, either a bad joint, incorrect V+ wiring or the wrong kind of capacitor used. I will look into incorrect capacitor type once i've ruled out the previous two speculations.

thanks


Yup, all the V+ points are connected together to the 12v dc source. Good luck with the debug, you can post your voltages and compare with completed units.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: TotemTek on April 03, 2009, 08:43:16 AM
my 0.47uF capacitors are polarised tantalum bead capacitors. have i made a bad?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 03, 2009, 12:31:51 PM
my 0.47uF capacitors are polarised tantalum bead capacitors. have i made a bad?

Yeah, they should be non-polarised caps, I don't think it would work with polarised caps:

.....I also have a question: usually transistor phase shift oscillators have three capacitors performing the phase shift - can they be polarised capacitors or should they be non-polarised?

If you can guarantee that at no time is the cap reverse biased by even a fraction of a volt, they can be polarized. Otherwise, use NP or film.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: solderman on April 03, 2009, 01:23:35 PM
my 0.47uF capacitors are polarised tantalum bead capacitors. have i made a bad?
Hi
No. I don't think so Most caps are exchangeable as long as you keep in the correct volt range and orient them correct if there polarised. Check http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ#CAPACITORS (http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ#CAPACITORS) and let + facing the trannies and - to the left in the chem.

//Solderman
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on April 03, 2009, 04:51:59 PM
Yes !!!  I got my add on board oscillating an LED :icon_cool: This is Ricks layout that I'm talking about.
I made another board and mounted sockets for the transistors and some of the resistors.
This allowed me to be able to temporally hook up an LED  between the collector of Q2 and V+ 12 volts and make it flash.
With the first board I made, I did not test it with an LED, just my meter which did show the base of Q2 fluctuating.
Now for the next test is to hook it up to my existing ValveCaster and see if I can get it to work.

Thanks Rick and Solderman for your help
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: TotemTek on April 03, 2009, 05:08:22 PM
good going biggy boy!  :D

thanks for your replies guys, now i'll stop bugging you and go debug my pedal.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 03, 2009, 06:27:58 PM
Yes !!!  I got my add on board oscillating an LED :icon_cool:

Thank @#$% for that!  :icon_mrgreen:

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on April 03, 2009, 07:26:19 PM
Yes !!!  I got my add on board oscillating an LED :icon_cool:

Thank @#$% for that!  :icon_mrgreen:


LOL
Actually when things don't go well, I don't get totally put off.
I look at it this way. If I make someone Else's project and it works the first time, I'm not really learning how the circuit works.
When a circuit is problematic (because of Me)  I spend more time working with it and tinkering with it, I learn more of how the circuit works.
It's all part of the learning curve for me.

Thanks for the encouragement Totemtec
Good luck with the debugging!!

OH one more question!
Is there enough adjustment in the depth pot to stop the effect. You know so that if I turn the pot all the way it won't effect the sound no tremolo
I ask this, because I'm not putting it into a stomp box it's going into a preamp rack with my Valvecaster or will I have to add a kill switch in the preamp cabinet to eliminate the effect?

Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 03, 2009, 07:42:08 PM
Is there enough adjustment in the depth pot to stop the effect. You know so that if I turn the pot all the way it won't effect the sound no tremolo
I ask this, because I'm not putting it into a stomp box it's going into a preamp rack with my Valvecaster or will I have to add a kill switch in the preamp cabinet to eliminate the effect?

Yup, with the depth pot fully counterclockwise, you'll get no trem, the cathode will be grounded as in the second stage of a stock Valvecaster.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: TotemTek on April 04, 2009, 09:35:51 AM
here are some voltages -

Q1
E:0
B:11.51
C:11.55

Q2
E:0
B:11.56
C:12.08

i'm not sure if those voltages are right... i've checked over the circuit several times, i've wired it all up very nicely, it all looks correct. getting absoloutely no signal when pedal turned on. think i'll swap out 0.47uF caps for NP ones
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 04, 2009, 10:54:55 AM

here are some voltages -

Q1
E:0
B:11.51
C:11.55

Q2
E:0
B:11.56
C:12.08

i'm not sure if those voltages are right... i've checked over the circuit several times, i've wired it all up very nicely, it all looks correct. getting absoloutely no signal when pedal turned on. think i'll swap out 0.47uF caps for NP ones


Sorry you're having trouble getting it going, Here's some info that should help your debug from page 6 of this thread:

OK. Pretty hard to get voltages from an oscillating oscillator!

This first set were taken with the PSO oscillating, but with the depth control removed. I still have the original PSO in a little corner of my breadboard right now. The blank values are because they are changing as the PSO oscillates.

Q1

E: 0.032
B:
C:

Q2

E:
B:
C:11.92


This second set of voltages were taken with the depth pot removed and the speed pot removed to stop the oscillating. Probably more meaningful.

Q1

E: 0.032
B: 0.657
C: 5.54

Q2

E: 4.96
B: 5.53
C: 11.92

I hope this helps. I suggest you remove the speed and depth pots and check the voltages against mine, just work with the PSO part of the circuit, thats where your problem is.

You can get a visual check on oscillation by inserting a red LED between Q2's collector and +ve. It will flash a little weakly though. You should remove it before you complete your build, as it will cause ticking otherwise.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on April 04, 2009, 11:32:06 AM
I've done the next stage of testing.
I have left the LED in the circuit to make sure the add on oscillator keeps oscillating when hooked to pin 8 of the second stage of the tube (valve).
So with the add on board hooked up to pin 8 the board keeps oscillating LED keep flashing, but there is no effect.
The amp has the same sound with and with out the oscillating circuit connected.
Turning the depth pot does not cause the effect to work just makes the volume change slightly at the two extreams of the pot it is the loudest if the pot is set anywere else the volume is reduce slightly. I also tested it with the LED removed and the collector reconected to the circuit directly.

Rick what does the last section of the circuit do in relation to the second stage Cathode? The section I have circled in the diagram, the voltage divider.
Does it create a modulation ( vary the resistace to ground from the Cathode), which would causes the gain to increase, decrease, increase, decrease........
Or does it connect, disconnect, connect, disconnect....... the Cathode to ground?

Keep in mind my ValveCaste ris using 157 volts to the anode plate so the current though the tube would probably be higher, I'm thinking I may need to ajust the resistor values in that last section to make it work.

(http://i107.photobucket.com/albums/m297/biggy-boy/vibracastersection.jpg)


Thanks
Glen

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 04, 2009, 11:42:52 AM
Rick what does the last section of the circuit do in relation to the second stage Cathode? The section I have circled in the diagram, the voltage divider.
Does it create a modulation ( vary the resistace to ground from the Cathode), which would causes the gain to increase, decrease, increase, decrease........


With that pot full counter-clockwise the cathode is directly grounded. With the pot full clockwise the LFO modulates the cathode.

Is the PSO definately oscillating?

Maybe you should test your circuit with 12 volts at the plates, then you'll know it works. Then its a matter of tweaking it to work at higher voltage.

Rick
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: biggy boy on April 04, 2009, 11:56:41 AM
Rick what does the last section of the circuit do in relation to the second stage Cathode? The section I have circled in the diagram, the voltage divider.
Does it create a modulation ( vary the resistace to ground from the Cathode), which would causes the gain to increase, decrease, increase, decrease........


With that pot full counter-clockwise the cathode is directly grounded. With the pot full clockwise the LFO modulates the cathode.

Is the PSO definately oscillating?

Maybe you should test your circuit with 12 volts at the plates, then you'll know it works. Then its a matter of tweaking it to work at higher voltage.

Rick


Yes the LFO oscillates during the entire time of testing. The LED is located between the Q2 collector and v+12 volts it keeps flashing and I can adjust the rate at which it flashes with
the speed pot.

OK I'll try the 12 volts to the Valves and post back





Glen
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on May 19, 2009, 01:34:03 PM
(http://i210.photobucket.com/albums/bb292/frequencycentral/000_0002-5.jpg)

I sold the original, this is it's replacement.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on August 07, 2009, 07:49:29 AM
HI! Im guitarmaster & beginner diyer from russia. Sorry for my english.

I like valvecasters and other lowvoltage tube stompboxes, tremolo - it s very interesting!

At first i try one transistor oscillator schematic from Solderman - i dont like it, bad regulated deep of tremolo, no very good sound.  :icon_confused:

At second i try schematics from Frequencycentral - good old sound. Very GoOoOoOoOoD sOuNd!  :icon_wink:
Big sanks for the idea and schematics!

I designed in DLC "add vibrato module" 7x7 holes perfboard, and full "vibracaster plate" for "GAINTA G0473" box, 119 х 93 х 33 mm. Anybody need?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on August 07, 2009, 07:57:16 AM
(http://www.gta-modding.it/forum/html/emoticons/welcome.gif)

yeah, Rick circuit is so good...
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 07, 2009, 08:02:13 AM
At second i try schematics from Frequencycentral - good old sound. Very GoOoOoOoOoD sOuNd!  :icon_wink:
Big sanks for the idea and schematics!

Hehehe - so glad you like it, here's me drinking to your success:

(http://www.rstolley.com/mad-genius-4.jpg)

Welcome to the forum!

I designed in DLC "add vibrato module" 7x7 holes perfboard, and full "vibracaster plate" for "GAINTA G0473" box, 119 х 93 х 33 mm. Anybody need?

Please feel free to add your layouts to this thread - will be a useful addition for some people in the future.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on August 07, 2009, 08:24:18 AM
With pleasure I show

1) VibraCaster add-on oscillator module 7x7 holes. Designed by DiamondDog. Redesigned by GeorgeM2.  
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40260&g2_serialNumber=1)

2) on this base: VibraCaster 12at7 with partlist, 12volt. work. Designed by GeorgeM2. Indicator LED worked with left 3pdt i be test  in the evening, with only right 3pdt - worked correctly. Potentiometers "VOL" "TONE" & "GAIN" are shown not precisely, see photos. Tube socket mount reverce plate(!), see photos.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40259&g2_serialNumber=1)
i try 12au7, 12at7 and 12ax7 from ElectroHarmonics and Tung-Sol - 12at7 EH i biggest like...

3) without partlist, best view wire
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40264&g2_serialNumber=1)

4) my maquette:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40267&g2_serialNumber=1)
In a box while is not drilled hole for the indicator, I will make it in the evening. gain poti - dublied 2x100k, in parallel - no more hum.  :icon_biggrin:
Boxart - decal paper + laserjet.  :icon_biggrin:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40270&g2_serialNumber=1)
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40273&g2_serialNumber=1)
big green caps - soviet type K71-17, look as from a scrap  :icon_eek: but sound is good, blue - K71-7, yellow "C3" no electrolit(!) - it s china mft type cap.
big caps - big sound  :icon_wink:

Best regards, George (Anatoliy Martynenko).
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: edd101 on August 07, 2009, 09:33:29 AM
привет!

и добро пожаловать!

Эд)))
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on August 07, 2009, 11:23:02 AM
what!?

Anatoliy, I am sure your Vibracaster will turn out GREAT!!! I like the design of the box...And yeah I love AT7 too!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on August 08, 2009, 01:11:04 AM
I do it!

1) guts:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40279&g2_serialNumber=1)

2) top view
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40280&g2_serialNumber=1)

3) The Ventures - "Vibrations" from my modded (  :icon_wink: ) FenderBluesJunior? It s better than sex!  :icon_biggrin: :icon_biggrin: :icon_biggrin:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40284&g2_serialNumber=2)

Upd: green caps type K71-7B, in previous post error.

p.s. About "strange blinking LED": i have this "problem" and i think: on the maquette i use soviet type green LED "AL307", his the blinking correctly, after i use blue china LED - his blinking BLINK-blink-blink-blink-BLINK-blink-blink-blink (I don t have oscillograf  :icon_sad: ) - 4 times on the one tact. Why?
 :icon_idea: - AL307 is the first generation LED, rough, low light, blue LED - is the modern LED - HI light, hi sensivity(?).
fin: For me it not a problem. For other - may be simply increase R14? Or use old bad LED  :icon_wink:

p.p.s.a box no have ventilations holes - nevermind! I 'burn" 8 hours power on - air temp = 18 grad. celsius, box temp = 25 grad. celsius, power adapter temp = 45 grad. celsius.  :icon_mrgreen: :icon_mrgreen: :icon_mrgreen:

p.p.p.s. Once again: soung is fantastic! (http://www.guitarplayer.ru/forum/Smileys/classic/elvice.gif) (http://www.guitarplayer.ru/forum/Smileys/classic/clapping.gif)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 08, 2009, 06:58:52 AM
That's a really well thought out build Anatoliy, I like the way it all fits together in the enclosure with the tube tucked safely away, and the board mounted pots too - a man after my own heart. Nice.  ;)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on August 08, 2009, 09:08:25 AM
Sanks!

Well, but not ideally, It is a lot of wires, not accurately. Blue caps and 3/4W resistors in oscillator - not very fine. Has made from this that was :icon_confused:
And on the right on a board there was а lot of an empty place, may be need add spring reverb?  :icon_biggrin:  :icon_mrgreen:

This - "his father", ValveCaster, PtP soldered, my previus project.
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40287&g2_serialNumber=1)
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40290&g2_serialNumber=1)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: station on August 09, 2009, 12:39:43 AM
Hey guys - Awesome project FC! Thanks for making an awesome pedal even better. I've been playin around with the valvecaster and I've been wanting to build a tremolo circuit for a while. So this one ended up on my breadboard tonight. Great sounds.

One critique I have of the design is the depth pot. People have mentioned that turning the knob down effects the gain of the circuit, and I noticed that too. I also heard a bit of a swishing sound while turning in the middle of the pot, then a bump at the end of its turn. Nothing terrible, but I thought I'd try to tweak it a bit. Here's what I came up with:

(http://i468.photobucket.com/albums/rr48/lyongraulty/Picture3.png)

I moved the 4.7 resistor to the middle lug of the pot moved the "anti-pop" cap along with it. This seemed to fix the gain problem. smooth levels all the way up and down. And with lug one still shorted to ground, the oscillator still shuts off completely on zero. The bump still happens when the wiper reaches ground - oh will, no biggie.

I also lowered the 47k resistor to 10k to get faster speeds.

(sorry for hacking up your schematic too  :icon_neutral: I hope you don't mind  :icon_wink:)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 09, 2009, 03:44:49 AM
Hey Station, thats a neat solution. Re. the bump when the wiper reaches ground, if you've still got the circuit on your breadboard try adding a low value resistor between the pot and ground - say 1K or around that value. I've noticed the same thing with my Valvecaster.

Re. the depth pot affecting the gain, I still can't decide if this is 'real' or 'percieved' - a Keeley modded Boss TR-2 for example has an extra volume control to combat the 'percieved' volume loss when the depth is engaged.

Nice work anyway - good to see this project maturing.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on August 10, 2009, 04:56:51 AM
My LED wired stupid,   :icon_frown:

Right:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40305&g2_serialNumber=1)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: station on August 14, 2009, 11:34:24 AM
That's an interesting idea - perceived volume loss. I think perception is reality though. And I like the way the mod makes the output a bit louder at the top of the wave. The pulsing is more balanced at the lower extremes and pronounced at the higher ones. It's kind of like a modulation effect, where you want to set the wave above and below the original, not just dipping down below it.

By the way, I really like the LFO circuit. I noticed you used in the tube vibrato pedal you came up with. Can't wait to try that out when I get some photocells.

I just made a modular version of the LFO on perfboard so that I can easily plug it in into different effects on my breadboard. This could yield some interesting sounds. I'm trying to use it to do a modulated auto wah, but I can't find the right circuit.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on August 14, 2009, 11:39:30 AM
I had help from R.G. with the LFO: http://www.diystompboxes.com/smfforum/index.php?topic=70056.0
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: station on August 14, 2009, 01:38:32 PM
awesome! thanks - I'll have to check that out when I can really absorb it.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: w437776 on August 17, 2009, 01:51:30 PM
here's my layout:
(http://i297.photobucket.com/albums/mm230/w437776/render.gif)
..and PCB:
(http://i297.photobucket.com/albums/mm230/w437776/PnP.gif)
Title: 1 year old!
Post by: frequencycentral on August 18, 2009, 12:21:15 PM
^
Nice looking layout!

Happy birthday to the Vibracaster thread - one year old today!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on August 24, 2009, 07:42:16 AM
HI! I tested "Station mod" - Less pulses in pauses, but too deep depth... deepestissimo... no very good, imho.
and i add One more 100k anode resistor(to sekond triode) consistently in "vibra" mode - It has balanced loudness without more gain.

p.s. Happy birthday! ;-)

p.p.s. to w437776 - i dont undestand, why 4 capacitors 0.47mf ? thanks.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: w437776 on August 24, 2009, 08:26:47 PM
HI! I tested "Station mod" - Less pulses in pauses, but too deep depth... deepestissimo... no very good, imho.
and i add One more 100k anode resistor(to sekond triode) consistently in "vibra" mode - It has balanced loudness without more gain.

p.s. Happy birthday! ;-)

p.p.s. to w437776 - i dont undestand, why 4 capacitors 0.47mf ? thanks.
sorry for the mistake, layout and pcb reuploaded.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: station on August 26, 2009, 08:59:36 AM
Thanks the feedback on my mod. It's really two mods: one changes the depth limit, the other effects the gain and evens out the wave pulse along the travel of the depth pot. The depth limiting resistor was originally a 47k. I changed it to 10k to get more depth, but you can change it back and not effect the main part of the mod.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: UKToecutter on December 29, 2009, 04:16:35 PM
Damn,

So many circuit diagrams / mods etc

Can someone point me to the 'final' 12V version circuit diagram please.   

 :)

Andy
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on December 29, 2009, 06:00:38 PM
Damn,

So many circuit diagrams / mods etc

Can someone point me to the 'final' 12V version circuit diagram please.   

 :)

Andy

Well. That would depend if you want to do the 6111 submini version or the 12AU7 version. And if you want the tremolo only version or the drive/boost/tremolo version.

I think this is the most common version: http://www.diystompboxes.com/smfforum/index.php?topic=70160.msg566503#msg566503

.....but add the 3.3uF cap as in this version: http://www.diystompboxes.com/smfforum/index.php?topic=70160.msg576174#msg576174
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: UKToecutter on December 30, 2009, 08:02:03 AM
Yep,

Too little information, I know.........

Tremelo only (I'm gonna build a seperate ValveCaster) and 12AU7 tube.

I think I'll incorporate Station's mod on the anti-pop cap location.

I think I got it all.

Guess I'd better get ordering parts

Any suggestions as to the best UK based supplier to use?

Andy
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: isildur100 on February 26, 2010, 03:05:46 PM
I just built this vibracaster and I really like it! It's a really cool tremolo! Thanks a lot for making this cool circuit available!

I made some modifications to it, notably a switch for clean/dirty sound and I tweaked the values of the oscillator in order to put a rate led without any audible clicking. I noticed that the choice of transistors really made a difference regarding the oscillator noise and clicking. I also used different values for the rate pot and associated resistor in order to get really fast rates which I was not able to get with the stock version.

I was also wondering, do you think it could be possible to make an all-tube vibracaster? I mean, replacing the 2 trannies of the oscillator with another 12au7 tube?

Maybe this question was already asked but I didn't read the whole 12 pages of this thread... :)

John
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on February 26, 2010, 04:01:09 PM
I just built this vibracaster and I really like it! It's a really cool tremolo! Thanks a lot for making this cool circuit available!

I made some modifications to it, notably a switch for clean/dirty sound and I tweaked the values of the oscillator in order to put a rate led without any audible clicking. I noticed that the choice of transistors really made a difference regarding the oscillator noise and clicking. I also used different values for the rate pot and associated resistor in order to get really fast rates which I was not able to get with the stock version.

I was also wondering, do you think it could be possible to make an all-tube vibracaster? I mean, replacing the 2 trannies of the oscillator with another 12au7 tube?

Maybe this question was already asked but I didn't read the whole 12 pages of this thread... :)

John

Sounds like a redesign to me.  :icon_lol:  It would be great if you could post a schematic for your version, sounds excellent!

I did a bit of research into tube phase shift oscillators, and it really needs to be a 12AX7 operating at high voltage to do the job. I guess it should be possible to do this with a charge pump or SMPS to get a high voltage. But ultimately I'm not sure that the ear would perceive much difference between a transistor PSO and a tube PSO, it's the same waveform after all.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: isildur100 on February 28, 2010, 01:36:11 PM
Here is what I did. I have tweaked lots of component values to my taste. It is not really a re-design since I followed much of the original design.

(http://www.upload-mp3.com/files/159067_jukdk/vibracasterMods.png)

First, the diode did not really make a difference except reduce the depth. I tried it with 2N5089's and it did not tick. Trying different trannies, I stumbled on some that ticked a lot. The bc414B was the less noisy of all but I think it may be hard to find. So the 2N5089 is the best choice for most of us. In that case note that you must use a 330k resistor instead of 100k where the speed pot is connected.

Another thing I noticed and that is valid for the valvecaster too is about pin 4 and 5. Notice that I have reversed them (gnd on 5 and V+ on 4). It sounds less harsh like that, to my ears anyways :).

The original vibracaster lacked a bit of fast rates and "deep" depth. Using the values in my mods now make it possible to have really fast rates (think about the tremolo in Pink Floyd's Money) and setting the depth at maximum really chops the sound. Anyways, you may want to try the mods, it does not take much time. Tell me if you like it. :)

Again, thanks for your hard work on this project! I hope my contribution is worth it.  :P

John

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: GeorgeM2 on March 19, 2010, 05:11:55 AM
I was also wondering, do you think it could be possible to make an all-tube vibracaster? I mean, replacing the 2 trannies of the oscillator with another 12au7 tube?
I tried, but to achieve work oscillator at low anode voltage and it has not turned out. If to make high anode voltage - all idea of a pedal is lost.
%-(
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: savvy on April 17, 2010, 08:32:19 AM
Hi folks, is anyone still reading this post? I have a problem with my build,I built the valvecaster prior to seeing this and decided to add the trem'. Valvy works good with a 386 pwr amp section into my spkr cab but I cannot get the trem working with it!
I connect pin 8 to the 1n4148 and ground to the jack socket/amp ground.all I get is nothing until I turn the pot fully c/w and then that connects the 12au7 to grnd and the valvy powers up :icon_question:I have put an led from grnd to Q1c and that flashes and the rate changes as the pot is turned.
Voltages using a 9v battery are:    Q1 c=5.54  b=0.657  e= 0.032        Q2  c=9.0  b= 3.7   e=3.16 they seem in the ballpark  :icon_question:
To connect the trem part I am removing the pin 8 connection to grnd and inserting this circuit between pin8 and grnd, is pin 8 to grnd meant to stay connected?
Can someone help please?
 Thanks
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on April 17, 2010, 08:37:52 AM
What transistors are you using? Pin 8 should no longer be grounded.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: savvy on April 17, 2010, 11:13:06 AM
Thanks for replying, I am using 547c BUT I made a big boo boo! the led flashes when I connect to ground and Q1c not V+  :icon_redface:
I have tried and tried with this but no luck, I have just got some more 547c's and am going to rebuild it :icon_mad:
I was certain in my mind that pin8 grounds through the trem circuit but I thought I would ask the question to make sure.
Thanks again, any ideas?Barrie   ps if it don't work this time I will try the EA trem and build it in to the valvecaster as a pre'
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: savvy on April 24, 2010, 12:59:38 PM
 ;) well it works finally, I popped in a couple of new tranny's and presto, Just one thing tho' it seems the led works as I noted, by connecting to earth and 'c' of Q2, thats the leg with the connection to the Q1,3M3 and 10k junctions in case I have Q1/2 reversed.Is this correct?
Any way I now have a working trem and will start modding now :-\
Thanks for a really good unit, need to get a nice panel to fit the controls onto and build it into my speaker cab I made.I now have my Vibracaster into a 386 chip amp and then my speaker cab,lovely for a battery setup ;) Works great off a 12v motorcycle battery/cigar lighter socket or power pack.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: DiamondDog on May 05, 2010, 03:46:53 AM
Rick-

I know I've been away for a while- good to see you're still going strong with the tubes!  :D

Is there a definitive VibraCaster schem out there? I've 12AU7/U7 Version 3 (and 2 and 1) dated 180808; is there an "official" release after the V3?

Have you (or anyone else) tried stations and isildur100's mods from the previous page?

Cheers

DD.

(FWIW the "clean" Valvecaster @ 12v has put up with touring for about year now- congrats to all involved.  :icon_cool:  )
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on May 06, 2010, 03:17:46 PM
That's the latest version. I did build a Vibracaster oscillator into a submini amp recently: http://www.diystompboxes.com/smfforum/index.php?topic=83831.0

I changed a resistor value (from 47k to 8.2k), largely because I was getting only very subtle tremolo, due to the running at higher voltage - probably not a good idea on a 12v build. One thing I did find useful was hooking a 0.47uF cap from the cathode to ground, thing got rid of the slight volume drop between 'no trem' and 'some trem'. A 100R resistor between lug 1 of the depth pot and ground (instead of directly grounding lug 1) is also probably a good idea, as it should cut out that slight 'thunk' when you turn the depth to minimum. I really should breadboard the Vibracaster again _ I've learned a lot since I first did it!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: sundgist on July 17, 2010, 06:37:23 PM
After building my valvecaster, liking it, and realising I don't have a tremolo. I went ahead and made this stripboard layout for the vibracaster LFO taken from Rick's vibratone schematic. Pot connections may need reversing.

(http://www.sundgist.talktalk.net/Layout/Valvecaster/ValveTremAdd.gif)

Verified and working well.

I'm running it off the regulated 12.6v heater supply. My valvecaster uses a 12at7 and runs on 21v, it also worked well wired to this. Had a bit of ticking which was removed by putting a 220uf cap across the + and gnd. The 8k2 resistor may need changing if yours runs on other voltages. 27k gives me a nice range from subtle wobble to chopping. 47k is stock for 12v.

Added a flashing rate LED. Based on Taylor's rather artistic post here.
http://www.diystompboxes.com/smfforum/index.php?topic=79078.msg657184#msg657184 (http://www.diystompboxes.com/smfforum/index.php?topic=79078.msg657184#msg657184)

...and added to the vibracaster schem like so.
(http://www.sundgist.talktalk.net/Layout/Valvecaster/Vibracaster-rate-LED.jpg)

I've put the LED on the emitter as the non inverted signal makes it flash clearer. Flashes on rather than flashing off.
I'd be interested to know if there should be any reason not to do it this way.
I tested it with various gain settings and checked with a scope. Works well and doesn't affect the sound or LFO waveform, not a tick or bump to be seen.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: El Heisenberg on July 27, 2010, 04:05:02 AM
Is there nothing else I can use but the BC547? I've never had these transistors.

I tried it with a 2n5088 and a 2n4011 cos all I had left were one of each and it don't work.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: El Heisenberg on July 27, 2010, 05:13:19 AM
Well I got it working. The depth control doesn't sound good with the volume turned low. Just kinda, mushes it up.The .47 uf cap after the diode really worked wonders. I had to use two .22 caps for every .47 caps cos I can't find .47 anywhere I can drive to. I also changed the 47k resistor to 27k. Way to choppy at 8k2. Nothing at 47k. I'm running it at 17.5v right now, but I plan to use 21v.

Anyway, I was thinkin if the depth control problem isn't cos of the transitors I used, then why have the depth control set up this way? Why not just jigger with the 47k resistor?


Also, I just replaced the 10k resistor to a 6k8 followed by an LED. Why not do this?? It's working.

The gain control is useless to me. It only sounds good when it's open. Whenever I put any resistance there, I get buzzing noise. This could just be the bad tube. I know for a fact it makes noise....It's too bad, I wanted to put a switch so I could just switch out a 100k resistor or a shunt to ground. But the fixed resistor gives me noise too!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: El Heisenberg on July 27, 2010, 05:55:33 AM
BTW i'm using a 12AU7 tube. Heaters are AC 6.3v

Stuck a .1 uf cap in parallel with the 100k resistor from pin 3 to ground and it's fine now. I don't have room for more than one more volume/gain control in the amp I'm adding this to though. I think I will use a DPDT switch to engage the tremolo, but  it'd be cool to have the overdriven valvecaster tremolo with it also. Choices choices.

I don't get any problem with using the 6k8/LED instead of the 10k in the tremolo circuit. I'm not getting ticking.


I still hate the depth control
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: El Heisenberg on July 27, 2010, 07:24:20 AM
Well I was using a bad pot for the depth control. All is well now. Works great. Don't even need a switch to engage it. I could just wire it like this cos the depth control goes down to no audible tremolo. I hope that's what it's sposed to do.

 since I will be running the tube plates at 21v (right now I'm using a different transformer to test this and I'm running the plates and LFO circuit on 18v) should I also run the transistors at 21v?? I was gunna run them on regulated 12v I have in the amp already for the reverb but I dunno if that'll mess with the tube stage when I engage the tremolo.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: El Heisenberg on July 27, 2010, 08:17:15 AM
datasheet says the transistors can do 30v max. Guess I'm in the clear? wonder if it'll add noise....

I don't wanna power this thing with all DC. I could run it all off the 12 regulator, but I'd like 21v on the plates and heaters on AC.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: El Heisenberg on July 27, 2010, 11:11:52 AM
:( I wanted to run this vibracaster before my digital reverb which is before my 12au7 preamp. But I think the tubes output is way too much for the digital reverbs input. The reverb circuit is the General guitar gadgets belton circuit. Im running that on regulated 12v and there's a LM7805 giving 5v to the belton reverb brick.

I still dunno how all this works really. Is the tube about running at 18 or 21v too much for inputs of TL072s running at 12v?? With much distortion the reverb starts to fart. Ugly distortion. Goes away after the initial attack.

I'm still gunna put the vibracaster before the reverb. I can't have tremolo after reverb.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on September 30, 2010, 11:58:05 PM
Found my problem! DC current getting into the oscillator. The problem was obvious and the fix was simple ;)

This weekend was a tube weekend. Finished my 18W (waiting on tubes to test it) and I finished this...

(http://img.photobucket.com/albums/v610/kurtlives/DSCF0264.jpg)

(http://img.photobucket.com/albums/v610/kurtlives/DSCF0267.jpg)

It sits beside it's twin the Valve Caster and looks awesome!

For comparison...
(http://img152.imageshack.us/img152/529/dscf0129bi9.jpg)

Great pedal! Thanks Rick.

Ok, I was to build a simple valvecaster, buy I stumble upon this and the design by GeorgeM2. I hope you guys, GoergeM2 and Kurtlive could help me to make my mind. I just need to know if GeorgeM2 design is booster/overdrive too, and how exactly Kurtlives wire the DPDT and 3PDT switches. Could you, please, tell me?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 01, 2010, 12:02:25 AM
I was thinking of using a DPDT.

One side selects normal trem circuit the other shunts the second triode's cathode to ground.

The other side of the switch for LED.


This is the part I just don't get.  :icon_cry:
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 03, 2010, 02:04:01 AM

(http://img.photobucket.com/albums/v610/kurtlives/DSCF0267.jpg)


I just need to know if GeorgeM2 design is booster/overdrive too, and how exactly Kurtlives wire the DPDT and 3PDT switches. Could you, please, tell me?

Sorry, one month ago I didn't even knew that there were something call "capacitor". But I'm a fast learner, hope that will help. I just realize that GeorgeM2's built is a booster/overdrive too, and I realize that the above image shows the circuit where kurtlives put the 7812 and it's companion capacitor, but I see too another two capacitors and I'm still  wondering how to wire the DPDT and the 3PDT, could you post a layout? Or just a simple explanation could be enough.

I was trying to decide: GeorgeM2 or kurtlives built and finally that little voice inside me speak up: "What the hell, build both". So I'm starting right know with George's, since I have figured it out completely, (or so I think).
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 03, 2010, 05:39:35 AM

...3) without partlist, best view wire
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40264&g2_serialNumber=1)


...Best regards, George (Anatoliy Martynenko).


I came up with a PCB layout for Anatoliy design, could please somebody check if it is right? I have doubts between in parts with poor visibility like volume 2, tone 3, pin 9, diode, etc.

(http://img838.imageshack.us/img838/8153/vibrapcb01.jpg) (http://img838.imageshack.us/i/vibrapcb01.jpg/)

Note that I added a trail to connect tone 1 and volume 3 trying to avoid the wiring, is that right?

Hope somebody check this out. Thanks.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 03, 2010, 02:14:00 PM

Note that I added a trail to connect tone 1 and volume 3 trying to avoid the wiring, is that right?

Hope somebody check this out. Thanks.

I just realize why that can't be done, so here is the layout fixed.

(http://img832.imageshack.us/img832/1880/vibrabyn.jpg) (http://img832.imageshack.us/i/vibrabyn.jpg/)

EDIT: Volume 2 goes to output, not to ground, it's fixed.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 04, 2010, 02:12:48 AM
Ok, sorry again, the layout had the pin 9 connected to tone 2, now that is fixed.

(http://img541.imageshack.us/img541/1880/vibrabyn.jpg) (http://img541.imageshack.us/i/vibrabyn.jpg/)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: glenn.b on October 05, 2010, 08:53:34 PM
I think your making progress on this!  I will try this!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 06, 2010, 12:45:11 AM
Howdy!~  My name is Glenn, I often do not say much in the place where there are folks way smarter than I on this, but I have to ask; Are you considering building the GeorgeM2 tremolo shown on page 11? Of "Vibracaster..or how to turn your..into a Tremolo?  Just curious.  I have thought of doing it on perfboard, just like George did, I have all the parts; but I look at the layout, and the pots, installed backwards &upside-down, and lol, I quickly get confused just looking at it!  Anyway, I just wanted to know if you were into this build, and if so how that is going for you.  At some point I will overcome my nerves on it and just go with it!
                                                                         Glenn

That happened to me too. The layout I posted is in the way it should look already printed on the board.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: glenn.b on October 06, 2010, 09:13:55 PM
Coolness!  That was what I was struggling with-the termination of several components were hard for me to see-that little piece was the missing link!  I'll keep you posted I  NEED to do this! ;D
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 16, 2010, 12:20:45 AM
Ok, this is where I say: "ŅAh, verdad?" :-\ First, the led is always on, is that right? I think theres something wrong with the wiring. I hope it is. When I turn the bypass off, I have no sound, so, it is not working. :-[ I really hoped this to work at first time 'cause I'm not very good in debugging, but it has to be done.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 16, 2010, 11:46:05 AM
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40264&g2_serialNumber=1)


My LED wired stupid,   :icon_frown:

Right:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40305&g2_serialNumber=1)

I find the wiring layout a little bit confusing so I'm tring to sort it out, I really hope that here lies the problem.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 16, 2010, 12:08:14 PM
 ??? Well, I'm giving up on GeorgeM2 design, I'm very confused with the two switch wiring, I can't figure it out by my self, and this tread seems dead, I'll try the last layout Renegadrian posted. Hope it works at first time 'cause debuggin alone, for me is nearly imposible.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on October 16, 2010, 12:10:19 PM
Don't give up. It's probably just a small wiring error. I'll try and get around to having a look over your wiring scheme.  ;)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 16, 2010, 09:52:45 PM
Ok, I'm not giving up...yet  :P I'm a little anxious for hear my own vibracaster roaring but, hey, I wouldn't got this far without some patience and your help. So, this is how I wired the 3pdt and the dpdt switches:

3pdt (bypass) switch:

(http://img151.imageshack.us/img151/7404/vibracaster3pdt.jpg) (http://img151.imageshack.us/i/vibracaster3pdt.jpg/)



Firs pole: lug 1 --> Pin 2 (through the 47nF capacitor)
              lug 4  --> In tip
              lug 7  --> Jumper to lug 9

Second pole:

lug 2 --> Led and dpdt's lug 6 (firs suspicious connexion)
lug 5 --> dpdt's lug 4
lug 8 --> not connected

Third pole:

lug 3 --> Volume central lug
lug 6 --> Out tip
lug 9 --> jumper to lug 7

Wiring of dpdt switch (tremolo switch):

(http://img151.imageshack.us/img151/6666/vibracasterdpdt.jpg) (http://img151.imageshack.us/i/vibracasterdpdt.jpg/)

first pole:

lug 1 --> dept central lug
lug 3 --> diode 4148 -- > pin 8
lug 5 --> In ground and jumper to lug 6

second pole:

lug 2 --> Q3
lug 4 --> 3pdt's lug 5
lug 6 --> 3pdt's lug 2, Out tip, and jumper to lug 5



(http://img258.imageshack.us/img258/1827/vibracasterbothswitches.jpg) (http://img258.imageshack.us/i/vibracasterbothswitches.jpg/)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 17, 2010, 06:49:41 PM
I just realize that dpdt's lug 6 must go to out ground and not Out tip.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 17, 2010, 07:34:50 PM
When I cut the wire "3pdt's lug 2" ---> "dpdt's lug 6" The led led turns on and off with the 3pdt switch and responds to oscilation when active it with dpdt switch, but still have no out signal.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on October 19, 2010, 02:39:51 AM
I rewired again and can't find the problem, its seems to me there's a short somewhere, or maybe the tube is not working propertly, or still the switches wiring are not right. I'm going, in a few hours, to Guadalajara for Pixie's concert  :icon_biggrin: when I come back I'm going to start over, from the basics: Valvecaster. I'm going to build them all, Valvecaster, Twincaster, Vibracaster without Gain and Volume, etc. because this brings something very clear to me: I have a lot to learn. See you at the weekend.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on November 11, 2010, 12:41:51 AM
I built my valvecaster, it was a success. I'm watting for some stuff to arrive and start building a Twincaster. In the meantime I tried again with the vibracaster. This time I used the Adriano's layout on page 5. Nothing ??? Is something with the wiring, Im sure. I just get a bad gronding sound. I'm using BC547c These are my readings:

Q1

E: 0.626
B: 0
C: 5.26

Q2

E: 5.26
B: 8.4
C: 11.87

They are not oscilating at all.

The readings on the pins are:

Pin 1: 3.4
Pin 2: -0.31
Pin 3: 0.05
Pin 4: 0
Pin 5: 11.86
Pin 6: 0
Pin 7: 11.86
PIn 8: 9.56
Pin 9: 5.86

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on November 11, 2010, 12:59:43 AM
I changed the transistor to see if they were the problem. Voltages are the same except Base of Q2, it droped down to 4.27
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on November 11, 2010, 12:27:19 PM
Sorry, my mistake, a toke those readings without the tube in the socket, with the tube, the readings are the same.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on November 18, 2010, 10:18:13 PM
Third attempt. Failed.  :-\ Speed pot does nothing, Depth pot increases and enormous amount of Gain, an enormous amount! Voltages on Q1 and Q2 are in 0 I have soldering issues, I couldn't find strips vero, so I get tripad. I tried to solder everything making jumpers. Now I'll try to relocate components to build it with as few jumpers as possible. I think 4 are going to be enough. Let's do it!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on November 21, 2010, 10:22:24 PM
Finally, SUCCESS!! I got my Vibracaster working. I still have the problem with the Depht draining Gain, I'll try with te 220k resistor on the plate. I relocated the components as I said and it worked. I think that what I used is not exactly tripad, here in Mexico City they call it "trama" a column of 4 holes paths between long vertical path lines. Well, the point is it's working. I think is time to try again with GeorgeM2's design.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kaalaraab on November 23, 2010, 06:24:25 PM
Suddenly, my vibracaster started to make a real loud noise, hum and his, like if it has ground issues and bad power supply issues. I think the Depht pot is damaged, I'll change it. A quick question, I want my speed to be real fast, how can I do it, will a 100k log pot do the job? Or I'll need to change the resistor value? Currently it is 4.7k.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on November 24, 2010, 02:19:01 PM
To increase the speed, reduce the value of one of the 0.47uF caps, it doesn't really matter which one. Alternatively you could do what I did here: http://www.diystompboxes.com/smfforum/index.php?topic=74262.0 Use a switch to alter the 22k (in the Vibracaster). 10k gives faster speeds, 100k give slower. The oscillator is called a phase shift oscillator, and has an inherantly narrow range of speed, hence the switch. Other designs using phase shift oscillators use a dual ganged pot to get a wide range of speeds: http://geofex.com/FX_images/FakeFenderVib3.pdf
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on December 19, 2010, 03:33:30 PM
I'd like to build the next Vibra with two dpdt switches, one will be on/off with millenium 2 for the led, and the other to switch the tremolo on/off with a dedicated led.
How do I have to wire that second switch!? THX
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on December 19, 2010, 06:34:41 PM
Adriano, I think the DPDT would select either the tremolo LFO or a resistor to ground. Or maybe just ground.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: Renegadrian on December 19, 2010, 06:47:36 PM
I guess I have to put the switch just after the diode from the cathode...!?So if it's on it lets the connection to the depth pot.
Is that so?!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: kurtlives on December 19, 2010, 07:08:55 PM
I guess I have to put the switch just after the diode from the cathode...!?So if it's on it lets the connection to the depth pot.
Is that so?!
Before the diode I think.
I forget, I know I did it though  ???. If you look back a few pages you'll see mine. Drive and trem in one box.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on December 19, 2010, 07:17:13 PM
BTW, on the Vibratone amp (http://www.diystompboxes.com/smfforum/index.php?topic=83831.0) I built, I added a 0.47uF cap to ground from the cathode which smoothed out the loss of volume of the depth pot.

I'd still say after the diode, as the diode is biasing. But try both ways!
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: markeebee on November 07, 2011, 10:41:42 AM
Oh ok, I'll go public.

I love the Vibracaster.  It's great, I love the old-schoolness.  I've made four so far, and I'm just starting another.  But.......

Has anybody come up with a way of switching off the trem without popping?  I've tried, but no matter what I do there's always at least a faint pop.  Best results so far came by switching the emitter of Q2 to ground.....totally noiseless when switching the trem off, but a lttle pop when switching on. 

Any ideas?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on November 07, 2011, 12:55:54 PM
Hey Markee, I think you should be able to use a switch to select what the cathode sees, either the depth pot, or a low value resistor to ground. I'd suggest trying 1K and see what happens - play about with the value until the static volume is equal to the modulated volume. I wouldn't advise directly switching the cathode to ground, as there's your pop.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: markeebee on November 07, 2011, 01:46:00 PM
Thanks Rick.  TBH I had already tried that, though.  Less pop, but still some pop. 

I reckon I should probably just live with it, but it really niggles me when I make something for a friend and they say "Yeah, I really like it, but if only.......". 
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: ~arph on November 09, 2011, 07:34:00 AM
How about quickly fading in the tremolo when switching on, so you go from zero depth to the depth set.  I'm thinking in terms of the anti-lockup on the PT2399.. Something with a cap charging up and a transistor slowly turning on.. Can do the same for switching off then too.. slowly discharge cap.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: jimipop on December 28, 2011, 08:09:44 PM
Hi there !

first, thanks for all this information we could find there !!! so cool

I'm a newbie with diy (and english, i'm french ...) but could anyone check at my layout ?
i made it with ressource on this topic but if you could verify it ...  :icon_redface:

I think i'll have a pop with the tremolo switch (pin 8 to ground etc).

(http://<a href="http://www.freeimagehosting.net/e5b64"><img src="http://www.freeimagehosting.net/t/e5b64.gif"></a>)

A great thanks !

Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: jimipop on December 28, 2011, 08:11:38 PM
 ???

there ...

(http://www.freeimagehosting.net/t/e5b64.gif) (http://www.freeimagehosting.net/e5b64)

sorry !
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: neurino on January 04, 2012, 03:45:37 PM
First of all thanks Rick for this nice tremolo.

I just breadborded this version

(http://s9.postimage.org/aapufpncf/Vibracaster_V3.jpg)

it sounds good but in my circuit the volume is not constant while turning the Depth pot.

With pot at about 25% I have no tremolo (depth = 0) and unity gain while under that value signal gets significantly boosted.

Above 25%  volume keeps almost constant, maybe with a little perceived loss, than it raises again reaching 100%.

Did you experience the same behavior?

I could live with it but it sounds weird to me having part of the pot acting as a boost, part as tremolo depth.

Any advice is welcome.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on January 04, 2012, 05:26:08 PM
The last time I built a Vibracaster was in this: http://www.diystompboxes.com/smfforum/index.php?topic=83831.0 ...which included a 0.47uF cap from between the cathode and the diode. That solved the volume issue for me.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: neurino on January 04, 2012, 05:34:04 PM
Thanks Rick, I saw your Vibratone and the cap, I will try it.

Did you experience the boost too with Depth pot to min? Just to understand if I may had done something wrong...

Another question, about the Vibratone tremolo part: you changed the res near depth pot from 47k to 8k2.

I tried some values but could not get what was changing in the overall sound, as depth changes.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on January 04, 2012, 05:39:22 PM
No, the depth was smooth with that cap in place.

The two resistors before the depth pot form a voltage divider. As the Vibratone was running on 80v it needed more voltage from the LFO to generate tremolo, hence the 8.2k instead of 47k.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: neurino on January 04, 2012, 05:41:44 PM
Ok, thank you  :)
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: HeimBrent on February 04, 2012, 02:20:18 PM
Breadboarded it a while ago, loved it, and finally got my self to put it together in a box, but... I seem to have built a Valvecaster. :/ I did the first design due to practicality, and now the tremolo-part won't work. Maybe if I tried building a Valvecaster I would end up with a functioning Vibracaster? Hehe.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on February 04, 2012, 07:57:19 PM
What transistors are you using?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: HeimBrent on February 05, 2012, 06:13:30 AM
That is a mighty good question. I've put the pieces so tightly together that I can't read it. It is howeverthe same ones that I used when I breadboarded it, and it worked fine there. But that's a while ago. You think they might be shoot?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: frequencycentral on February 05, 2012, 08:47:36 AM
I only ask because BC547C work, but BC547B don't - not enough juice.
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: blown240 on February 10, 2012, 10:03:10 PM
I am getting ready to build one of these in an enclosure with a regular Valvecaster and a Little gem.  Its basically going to be something that I can use as a practice amp, or bypass the little gem for an effects pedal.

Is there a Radio Shack number for the transistors?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: peterg on October 08, 2013, 12:44:11 PM
http://www.aronnelson.com/gallery/main.php/v/frequencycentral/Vibracaster+Stock+12AU7+V2.JPG.html (http://www.aronnelson.com/gallery/main.php/v/frequencycentral/Vibracaster+Stock+12AU7+V2.JPG.html)

i'm planning on making a two tube vibracaster using the attached single tube version as a starting point. I'll cascade the second tube. My questions are regarding the gain and vibra controls. Can I join the number 3 pins and send them to a pot for the gain and can I join number 8 pins together and send the signal to the diode at the start of the vibra section? Will I need stacked pots for this?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: peterg on October 09, 2013, 10:44:01 PM
Anyone?....
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: easilyamused on February 02, 2014, 09:53:00 PM
Anyone?....
I'm trying to do the same... I have two separate successful builds: a vibracaster and a boobtube (variant of valvecaster) already, so I'm about to try the grafting procedure. I'm trying to get my head around the possible switching to provide clean boost (V1), clean boost (V1) + tremolo, clean boost (V1) + dirty overdrive (V2), clean boost (V1) + trem + dirty overdrive (V2)... Will update when I come up with some ideas!

BTW I built both tube circuits as P-to-P right on the back of the socket. Tight, but works well.


Here's a shot of my work in progress. From left: the boobtube with only Gain Pot connected; MAX1044 powered charge pump (I'm using the 40V tap); The vibracaster LFO board with LED addition; Vibracaster tube portion. Ins and Outs are not fully finished - I'm planning the switching and wiring to actually be neat so I'm holding off until I get it straight!
 
https://www.dropbox.com/s/0cac56q08vjulwi/WIP.jpg
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: peterg on June 25, 2014, 03:36:08 PM
Does anyone have an up-to-date schematic of the vibracaster?
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: lluis3.0 on June 25, 2014, 03:52:28 PM
After building my valvecaster, liking it, and realising I don't have a tremolo. I went ahead and made this stripboard layout for the vibracaster LFO taken from Rick's vibratone schematic. Pot connections may need reversing.

(http://www.sundgist.talktalk.net/Layout/Valvecaster/ValveTremAdd.gif)

Verified and working well.

I'm running it off the regulated 12.6v heater supply. My valvecaster uses a 12at7 and runs on 21v, it also worked well wired to this. Had a bit of ticking which was removed by putting a 220uf cap across the + and gnd. The 8k2 resistor may need changing if yours runs on other voltages. 27k gives me a nice range from subtle wobble to chopping. 47k is stock for 12v.

Added a flashing rate LED. Based on Taylor's rather artistic post here.
http://www.diystompboxes.com/smfforum/index.php?topic=79078.msg657184#msg657184 (http://www.diystompboxes.com/smfforum/index.php?topic=79078.msg657184#msg657184)

...and added to the vibracaster schem like so.
(http://www.sundgist.talktalk.net/Layout/Valvecaster/Vibracaster-rate-LED.jpg)

I've put the LED on the emitter as the non inverted signal makes it flash clearer. Flashes on rather than flashing off.
I'd be interested to know if there should be any reason not to do it this way.
I tested it with various gain settings and checked with a scope. Works well and doesn't affect the sound or LFO waveform, not a tick or bump to be seen.


if i had a valvecaster, all i need is to wire lfo out to pin 8 ???

thank you
Title: Re: Vibracaster - or "How to turn your Valvecaster into a Tremolo"
Post by: disabled_shredder on January 22, 2015, 09:29:08 PM
I don't know if this thread is current or not but I have a big problem and want RESOLVE WITH THIS BUILD. I used version 2 12au7 version. I have great oscillation but I have a huge ground hum (or so that's the description I'll use) and the depth pot works but fully counter clockwise I get a major hum even more so than any other setting. I've shielded the input and output this driving me nuts because I repair amps and mixers as a second income. Does anyone have any thoughts? I'm thinking the input cap might be too high or the dc blocking caps need to be lowered also? Just a though. Would love any input.