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DIY Stompboxes => Building your own stompbox => Topic started by: drolo on July 29, 2013, 08:54:03 AM

Title: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on July 29, 2013, 08:54:03 AM
After midwayfair and samhay's builds (http://www.diystompboxes.com/smfforum/index.php?topic=101722.0 (http://www.diystompboxes.com/smfforum/index.php?topic=101722.0)  and http://www.diystompboxes.com/smfforum/index.php?topic=102736.0 (http://www.diystompboxes.com/smfforum/index.php?topic=102736.0)) fueled my curiosity about the Harmonic Tremolo found in Fender Brown Face amps (and some others of that era), I wanted to try my luck at emulating it.

(http://i1277.photobucket.com/albums/y492/drolobucket/TWINPEAKStremolo_zps2926f8d5.png)

I also found inspiration in 2 circuits on GEEOFEX where R.G. had already laid out how to emulate the sound of the Harmonic Tremolo (or Vibrato as Fender called it)

Here:
http://www.geofex.com/FX_images/FakeFenderVib2.pdf

And especially interresting for me, here:
http://www.geofex.com/FX_images/P90-to-fenderPro.gif

A few words about the circuit.

After the Input buffer the signal is split to a LP filter (around 1.6kHz) and a HP filter (around 3.3kHz). I found these to work the best but they can be tweaked to one's liking of course. The Tone knob is able to pan between bass and treble. The signal of each filter goes through an Optocoupler's LDR and is summed at the output stage (U1B). The output stage has a trimmer that allows to adjust the overall volume.

The Optos are Vactec VTL5C1. One could use others, even home made ones. Anything can be tweaked to work when correctly biased. I chose them over others because they had the best response time with fast square waves.

The optos can be driven either in phase or out of phase. In phase, it produces a

"normal" tremolo effect, as both bass and treble are modulated at the same time.
Out of phase, you get the "Harmonic Tremolo" where it pans between the bass and

treble signal. I have added 2 additional modes, one with only bass

modulation/fixed treble and on with treble modulation/fixed bass.

To switch these modes, I found these very nifty compact 2P4T rotary switches that were a blessing in order to keep this build rather compact while having the rotary switch and pots PCB mounted.

(http://i1277.photobucket.com/albums/y492/drolobucket/b51179a9-fee1-4a8e-8e9a-ad229cd3a9d3_zps3e68aa85.jpg)

I am using a TAPLFO PIC from Electric Druid, which is a very handy Tap LFO with multiple Waveshapes. Any other common LFO should work the same though. It would allow a much simpler layout an smaller box ;-)

The LFO's PWM signal goes through 2 inverting op amp stages to drive the Optos. The first one has a trimmer connected to the negative input that allows to apply an offset voltage to get the TAPLFO's signal (0-5V) centered around the half-supply bias voltage.

The 2P4T switch routes the LFO signal to the optos as explained above.

The biasing is easiest like this:
- Adjust the offset to get the LFO signal centered around the half supply voltage
- Adjust the 2 Opto's current with their dedicated trimpot to have the maximum swing without audible ticking.
- Adjust the volume on the Output stage.

If for example you get too much ticking, reduce the LED's currents and make up for the volume drop with the volume trimmer.

I went a bit overkill with the power supply as you can see. I may have been OK without the separate filtering on V2 but since I build everything on Perf and it was quite some work ... I did not want to risk having high frequency noise or LED ticking bleeding into the audio circuit...and having to start all over. When I first finished the perf, I had a strong high frequency whine but it all went silent when I boxed it up and used shielded wire for in and output.

Here is a small demo:



Thanks for all the people mentioned above and also others that inspired and educate me :-)




Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: midwayfair on July 29, 2013, 09:26:15 AM
a) Sounds awesome, and I like a lot of stuff about the circuit, especially how you did the CV output section and the rotary.
b) The contest starts in two days and this isn't an entry!?

EDIT: What's the Offset trimmer do?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on July 29, 2013, 10:15:41 AM
a) Sounds awesome, and I like a lot of stuff about the circuit, especially how you did the CV output section and the rotary.
b) The contest starts in two days and this isn't an entry!?

EDIT: What's the Offset trimmer do?

Thanks Jon!

About the contest, I had not really considered participating, especially with all the great builds I see around here ... Also I thought the entries had ended already ... :-/ since I posted this today, i guess I'm disqualified ..:-D

The offset trimmer is an idea I got from here:
http://www.geofex.com/FX_images/Panning%20LEDs.pdf

Without it, the first inverter would turn the 0-5V signal into a squashed 4.5-8.5V signal, and the second inverter again something like 1.5-4.5V. Very hard to bias and not clean at all.
The offset helps to shift the incoming voltage to ideally be centered around 4.5V so the first inverter puts out 7-2V and the second inverter, the exact inverted signal (in theory...) 2-7V. That way the signal does not hit the power rails of the OPamp and gets processed without being distorted.


Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: moosapotamus on July 29, 2013, 09:12:19 PM
Nice work! Yeah, sounds awesome! 8)

~ Charlie
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on July 30, 2013, 09:36:48 AM
Thanks Charlie :-)

On a more cosmetic note, I printed some graphics on matte/transparent sticker paper with a monochrome laser printer. I had done it previously with nice results when the design involved only fonts and simple shapes without any grayscales. With this one, as it incorporated a photo in the background (the Twin Peaks red room  :) )  it ended up looking like, pardon my language, smeared poo ...

Obviously my printer (a HP 1010) is not suited for photo prints but does any one have any tricks on how I can prepare the image to have the best results? reducing image depth? Dithering? Some moiré pattern?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: mistahead on July 30, 2013, 08:23:00 PM
Thanks Charlie :-)

On a more cosmetic note, I printed some graphics on matte/transparent sticker paper with a monochrome laser printer. I had done it previously with nice results when the design involved only fonts and simple shapes without any grayscales. With this one, as it incorporated a photo in the background (the Twin Peaks red room  :) )  it ended up looking like, pardon my language, smeared poo ...

Obviously my printer (a HP 1010) is not suited for photo prints but does any one have any tricks on how I can prepare the image to have the best results? reducing image depth? Dithering? Some moiré pattern?

Just go for half toning methods, they're the most impacting/forgiving at the same time for pretty much every type of "fiddly printing".
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on July 31, 2013, 11:21:44 AM
Just go for half toning methods, they're the most impacting/forgiving at the same time for pretty much every type of "fiddly printing".

True, it did look better on a test I made. But in the end I decided to go with a simpler design without images:

(http://i1277.photobucket.com/albums/y492/drolobucket/twinpeakstremolo_zps0f16e8ef.jpg)

Usually I never label my own pedals as I always remember what button does what. I guess I just wanted to go fancy for once... :-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: deadastronaut on July 31, 2013, 11:48:44 AM
excellent tremolo/build...

love that bass/treble blend too... 8) 8) 8)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on July 31, 2013, 05:14:15 PM
Wow  :o (I'm speechless)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: kaycee on August 02, 2013, 04:55:26 PM
Oh! My! That is supurb, what a lovely sounding tremolo, very  8)

Great project there, maybe you could get someone to make some boards for it? I'm sure you'd shift a few, me for one, sounds so nice and all those features, brilliant stuff!
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: samhay on August 03, 2013, 04:21:03 AM
Nice job. The blend control is a nice touch and works very well. How did you settle on the 3.3k crossover frequency?
The dual LDR approach is similar to Bajaman's Vibotrem (other forum), but you use it to maximum effect with the 4 mode selector, which is very cool and lets you A/B(/C/D) the harmonic tremolo vs normal tremolo properly.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 04, 2013, 02:38:02 AM
Oh! My! That is supurb, what a lovely sounding tremolo, very  8)

Great project there, maybe you could get someone to make some boards for it? I'm sure you'd shift a few, me for one, sounds so nice and all those features, brilliant stuff!

I wouldn't mind having some done ... I just don't know anyone who does that or how to go about submitting the idea ... to whom ... If you have any tips, let me know ;-)

Speaking of boards, here is how it looks like inside:

(http://i1277.photobucket.com/albums/y492/drolobucket/DSC_3123_zps8fb63198.jpg)

(http://i1277.photobucket.com/albums/y492/drolobucket/DSC_3114_zps30a0ccd9.jpg)

It's the first time I tried a split board with controls on a daughterboard. It allows to cram in a lot more stuff :-)
Initially I had tried to draw a doublesided PCB and have it etched but it was getting too complex for my poor PCB skills, plus I just could not wait the ordering time and perfed away instead ;-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 04, 2013, 02:48:11 AM
Nice job. The blend control is a nice touch and works very well. How did you settle on the 3.3k crossover frequency?
The dual LDR approach is similar to Bajaman's Vibotrem (other forum), but you use it to maximum effect with the 4 mode selector, which is very cool and lets you A/B(/C/D) the harmonic tremolo vs normal tremolo properly.
Weird that I had not come across Baja's project when I was researching about this ... It's a very similar approach.
I had tried the LDR's to ground/bias like he has but was not getting enough chop so I put them in series instead. The effect was much more pronounced.

1.6 / 3.3kHz seemed like the most pleasing when I was breadboarding. Now that I read Baja's description and interesting analysis of the original circuit, I realize the original had the crossover much lower ...
Strangely, when comparing, my trem seemed to sound a bit like the vids of the actual amp I could find on youtube ...  perhaps a bit colder...
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: samhay on August 04, 2013, 08:59:18 AM
The Tremulus Lune and its spawn use an LDR in series like you have - this approach seems to be work well, so good choice.

There is a fairly wide sweet spot in the crossover frequency of my Anharmonic tremolo, so I guess the filter's corner frequency is probably not especially critical. Ultimately, it doesn't matter what the cutoff frequency is on paper as long it sounds alright - which yours does.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: midwayfair on August 04, 2013, 09:27:44 AM
I get the sense that the crossover frequency needs to be different with each approach. The crossover the cardinal is all the way up at 7k, but it still sounded right next to the actual amp.

I'd say I'd give a layout a go, but my attempt to do Samhay's was a disaster. I suck at op amps. However, I do at least have a schematic with the tap tempo half if you want to use it. You'd just need to have the dry path done. They're separated pretty far on the PCB as well.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: moosapotamus on August 04, 2013, 12:56:52 PM
I might give a PCB layout a go. Love the sound of this. 8)

~ Charlie
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on August 04, 2013, 12:59:53 PM
I can have a go at a layout (doublesided, ready for a fab house) if you'd like. I've had some decent training with my latest project of getting the A/DA flanger in a 1590B ...
Just tell me which specifics you would like for your layout, such as pots mounted on pcb or tabs at the top, ... Any specifics you might have in mind.

Btw David, Vlaams of Waals/Flamand ou Wallon?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 04, 2013, 02:40:32 PM
There is a fairly wide sweet spot in the crossover frequency of my Anharmonic tremolo, so I guess the filter's corner frequency is probably not especially critical. Ultimately, it doesn't matter what the cutoff frequency is on paper as long it sounds alright - which yours does.

Seeing the different corner frequencies used in different projects and the results, I guess you are right : )
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 04, 2013, 02:42:44 PM
I get the sense that the crossover frequency needs to be different with each approach. The crossover the cardinal is all the way up at 7k, but it still sounded right next to the actual amp.

I'd say I'd give a layout a go, but my attempt to do Samhay's was a disaster. I suck at op amps. However, I do at least have a schematic with the tap tempo half if you want to use it. You'd just need to have the dry path done. They're separated pretty far on the PCB as well.

Yeah the 7k left me wondering, but in your design it does work very good.

It's kind of you about the layout, but for now I am satisfied with my perf, as long as it does not fall apart. All my diy pedals are perf actually, never made a PCB. But I am getting better at making solid and clean builds. I am already working on a new project and don't feel like spending time with something that is done and behind me :-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 04, 2013, 03:24:18 PM
I can have a go at a layout (doublesided, ready for a fab house) if you'd like. I've had some decent training with my latest project of getting the A/DA flanger in a 1590B ...
Just tell me which specifics you would like for your layout, such as pots mounted on pcb or tabs at the top, ... Any specifics you might have in mind.

Btw David, Vlaams of Waals/Flamand ou Wallon?

Thats great :-)

Here is the perf layout I used:
(http://i1277.photobucket.com/albums/y492/drolobucket/tremolo-layout_zpsff0c1eb2.png)

Maybe that can answer some of the questions

pots mounted on the perf as well as the rotary switch. I used some miniature ones as pictured in my first post. But for convenience I guess people find the bigger lorlins or alphas more easily. (although these little rotaries are amazing and cost next to nothing http://www.befr.ebay.be/itm/300881322642?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649  it's a hell of a deal!) just that if you use the lorlins, you will need the pcb mounted pots with longer legs :-)

I tried at some point to draw a double sided PCB but I was having a hard time getting the microchip and led driver traces separate from the audio traces (but it was also the first time I was trying to design a double sided PCB I have to admit ...)

If you get to do it and people are interested, I guess we could have some printed. I have never had a PCB printed so if someone knows good places that are not too expensive for small runs...

BTW I am neither Walloon nor Flemish, I am a Portuguese that kind of stuck around after his studies in Brussels ;-)
I understand Flemish quite well, since I speak German, but I never got to learn to speak, really.



Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on August 19, 2013, 09:23:40 AM
Nice one. Having the TAPLFO already, it's just a matter of a few more components and voila! Probably my next build!

Greetings from Sintra ;)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 20, 2013, 06:45:44 AM
Greetings from Sintra ;)

Ola !
I am originally from near Castelo Branco. I have been to Sintra once and found it a very strange place (in a beautiful and  good way) :-)

I wish I had the patience (and time) to learn how to code PIC chips ... crazy what you can do with those ...
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on August 21, 2013, 09:10:51 AM
Oi oi

My late grandmother was from near Castelo Branco also, I've been there, but many years ago!

The pics are a wonderfull world, besides that we also have arduinos, I've made a switch looper with one of those, but also have plans to do a simpler with PIC, already tested and working!

I've tried the tap lfo yesterday and it worked very fine, now only a matter of time of assemble all stuff into a pcb, perhaps later I'll design one. And if you don't mind, I can post here the drawing!
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 22, 2013, 03:48:57 AM
Sure, I would be glad if you post it, maybe someone else might be intereseted in using it.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on August 27, 2013, 03:38:02 PM
Didn't have time for PCB yet LOL, perhaps this weekend if time allows.

I'm thinking also in a autopan circuit, using the LFO, perhaps to include after this, or even separate building!
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on August 28, 2013, 01:32:18 AM

I'm thinking also in a autopan circuit, using the LFO, perhaps to include after this, or even separate building!

if you add a switch to remove C1 and C5 from the circuit and feed each channel to a separate output, it should give you a signal panning between the 2, in the "out of phase" lfo mode
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on September 01, 2013, 01:38:05 PM
Hello all!

I've made a hand draw diagram, to use also autopan on this!  I'll use only normal tremolo - harmonic and the rest of the switch will made the autopan function!

It's ok for you that I post here or you prefer a new topic?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on September 01, 2013, 01:51:52 PM
Hello all!

I've made a hand draw diagram, to use also autopan on this!  I'll use only normal tremolo - harmonic and the rest of the switch will made the autopan function!

It's ok for you that I post here or you prefer a new topic?
Ola :-)
Sure you can post it here, I'm curious to see it.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on September 01, 2013, 02:02:38 PM
Oi!

Using a 4 circuit 3 position, I use the first two for the lfo output. Then the other two, for the outputs of the ldr's and each one goes to a output... In normal mode or harmonic, only goes to output 1, in pan goes to output 1 and 2, (pan in harmonic mode, I didn't bypassed the filter section!)

I'm trying to test it in proteus!!

Later I'll try to scan the draw and post here, during the week ( hope so!) perhaps I'll post the pcb's, trying to design them, but it's like almost 10 years without drawing so i'm a little rusty!
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on September 01, 2013, 03:57:58 PM
Here's the draw... now that i'm looking, perhaps it could be even more simple, because the 1st led of the vactrol is always on... and one of the outputs of the ldr also... but i'll try another version and then put here!

For now, here it goes, version 1:

(http://img13.imageshack.us/img13/5997/i0ed.jpg)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on September 03, 2013, 11:52:59 AM
Here's the draw... now that i'm looking, perhaps it could be even more simple, because the 1st led of the vactrol is always on... and one of the outputs of the ldr also... but i'll try another version and then put here!

For now, here it goes, version 1:

(http://img13.imageshack.us/img13/5997/i0ed.jpg)

you're right you can do the same with a 2P3T, if I look correctly.

Now you made me want to make stereo version .... :-)
If you build it, post a demo!
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on September 03, 2013, 05:18:11 PM
Quote
you're right you can do the same with a 2P3T, if I look correctly.

Now you made me want to make stereo version .... :-)
If you build it, post a demo!

Shure! If time allows, this week I pretend to make some measures on scope and fine tunning the opamp section. But even if I make a breadboard version, it's still possible to take a few samples ;)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: nmbb on September 05, 2013, 04:47:02 PM
A pre-drawing of the lfo (without pots), using a double side board. Still rusty,but it can be improved:

(http://img841.imageshack.us/img841/1541/btbt.png)

First time I draw double sided boards!
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on September 22, 2013, 01:32:34 PM

The LFO's PWM signal goes through 2 inverting op amp stages to drive the Optos. The first one has a trimmer connected to the negative input that allows to apply an offset voltage to get the TAPLFO's signal (0-5V) centered around the half-supply bias voltage.

The biasing is easiest like this:
- Adjust the offset to get the LFO signal centered around the half supply voltage

 educate me :-)

Could you educate me on this one? :) Which voltage should I measure where exactly? If I am understanding this correct, I need to have 4.5V at the negative input of the opamp.

I noticed in your schematic that the multiplier does not have a 3K6 resistor between its pin 3 and 5V. Is this a mistake in your schematic? I would assume that without this resistor, the multiplier pot does not function as it is supposed to. (above 3,75V it goes to its default setting of x1)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on September 22, 2013, 05:58:13 PM
Here is how I do it:
Set the TAPLFO Depth to minimum, tat way you get a steady 2.5V signal
Adjust the Offset trimpot until you get 4.5V at the output of the first opamp (U3A)

About the multiplier you're right, but I left it like that intentionally as it provided me an easy to dial in x1 position (the one I use most) when I turn the pot full clockwise but still have all the other divisions available on the left :-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on September 22, 2013, 07:41:29 PM
Makes sense. Thanks for the extra info.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on October 05, 2013, 09:01:30 AM
I was wondering, if I set the output of U3A to be 4.5V, shouldn't I make sure the output of U3B is 4.5V as well? Right now I'm measuring 4.5V at the output of U3A and 3.59V at the output of U3B. Also, instead of attaching the VTL5C1 to 5V, shouldn't this be 4.5V as well to ensure there are no differences in volume? I don't have a dB-meter here or I would measure to make sure.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on October 05, 2013, 02:20:24 PM
In that case, your bias half voltage VB2 is probably not not 4.5v, like on my pedal. Measure VB2 and use that as value to obtain at the output of those op amps. Basically, dial the offset pot until you have more or less the same voltage at the output of the 2 op amps. As you turn it, you will notice that while one voltage rises, the other drops.

I just realized that the schematic I posted is not exactly what I ended up working with. As I had no 7808 regulator at hand, I just hooked the power of the op amps directly to R16. I also found out after drawing the schematics that the voltage regulators need around 2V of of voltage drop to operate correctly. So I would have needed a 10V supply ... ideally I would need a 7807 and a rail to rail op amp. But it works as is, I just need to think about setting the offset again if I ever change my power supply.

Concerning your question about the opto being directly connected to 5v in the bass only and treble only positions, it's always a bit of a balancing act, when you try to set a tremolo to have the same perceived level as in bypassed mode. It was convenient as I had a nearby 5V rail at hand on the perfboard and it turned out to sound well balanced. But every one has different taste and ears, feel free to try different settings ;-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on October 05, 2013, 02:34:40 PM
I'll have a look-see tomorrow then. Maybe a 9V zener could do the trick in place of the 7808? If I have one I'll try that and I'll also connect the bass/treble only to Vb to ensure equal output levels.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on October 06, 2013, 10:32:19 AM
Did some research on Zeners ...

When using the following schematic ...
(https://dl.dropboxusercontent.com/u/155894717/Zener.jpg)

First I would need to find out the equivalent load resistance of the circuit.
I am feeding it with a onespot which puts out 9.4V. Because R = V/I = 9.4V / x (current draw of the circuit) = Y Ohms.

To calculate the series resistance, I need to know which input voltages I would allow. Let's say 9-10V.

My zener is 500mW.

500mW/9.1V =  54.9mA and so,

R1_min = (10V-9.1V)/(x mA + 54.9mA) = z Ohms.

Quote
For real zeners a more practical rule of thumb is to ensure the zener current doesn't drop below about 1/10th it's maximum current.  
In this case the minimum zener current would be 5.5mA and

R1_practical_minimum = (10V-9.1V)/(x mA + 5.5mA) = z Ohms

Rs_max = (9.2V-9.1V)/x mA = z Ohms

If this is correct, then I still don't have a solution for the Rs_max if I feed the circuit with 9V. I guess the Zener just does not conduct anything and the circuit functions as before.

Could some mastermind perhaps shed some extra light?




Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on October 07, 2013, 05:31:39 AM
See, that is precisely why I gave up the Zener idea and decided on voltage regulators. Read a scary thread about zeners where someone (R.G.?) warned that mere mortals would have a hard time figuring out how to calculate the resistance to make them function properly ;-)

I have no clue how to calculate the impedance of the circuit. Would it help to have the current consumption? Would that be as easy as measuring the voltage across R16 and calculate I = V/R ? Also I noticed that as the optos light up, especially when they are set to work in phase, the voltage sags a bit. Could that complicate things? I guess I would need to measure the voltage across R16 when the Leds are lit on maximum.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on October 07, 2013, 11:42:00 AM
For current consumption you can just stick your DMM in series between your power source and your pedal. Then you can use the calculation of my previous post. The maximum resistance for the series resistor however, is one I'm very unsure about. If it's too high, the Zener will eat a lot of current and get hot. And there was my question about what happens if your input voltage goes below 9.1V.

As for the voltage sag, I assume that if the series resistor is within the proper range, it won't be a big issue. But yes, I think someone like R.G. would be very helpful to ensure we're on the right path here.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on October 07, 2013, 11:49:49 AM
For current consumption you can just stick your DMM in series between your power source and your pedal.

I forgot to mention why I would need to calculate the current instead of measuring it, the Amperemeter on my DMM for some reason is shot ...
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on October 07, 2013, 04:07:12 PM
Ok, I measured the current going to the 2 op amps U3. It draws 15ma when both optos are fully lit. at least in my setup, current draw may vary depending on what optos are used and how they are biased. BTW I experimented with different op amps and found the 5532 to work better than the 1458 and 4558 and tl072 I had around. They had the widest swing, exactly 5V.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on October 07, 2013, 06:08:58 PM
My 5532 did not work at all for some reason.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on October 07, 2013, 06:25:23 PM
My 5532 did not work at all for some reason.

weird ... I tried 2 different ones and both worked fine
next best, 1458 and 4558
TL072 was not so good
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Valoosj on November 16, 2013, 10:38:46 AM
When using the following schematic ...
(https://dl.dropboxusercontent.com/u/155894717/Zener.jpg)

First I would need to find out the equivalent load resistance of the circuit.
I am feeding it with a onespot which puts out 9.4V.

My DMM says I am using about 20mA. It goes up to 60mA if I set the brightness of the rate LED very high.

Because R = V/I = 9.4V / 20mA = 470 Ohms.

To calculate the series resistance, I need to know which input voltages I would allow. Let's say 9-10V.

My zener is 500mW.

500mW/9.1V =  54.9mA and so,

R1_min = (10V-9.1V)/( 20mA + 54.9mA) = 12 Ohms.

Quote
For real zeners a more practical rule of thumb is to ensure the zener current doesn't drop below about 1/10th it's maximum current.  
In this case the minimum zener current would be 5.5mA and

R1_practical_minimum = (10V-9.1V)/( 20mA + 5.5mA) = 35 Ohms

Rs_max = 9.1V/55mA = 165 Ohms


I get the feeling I am missing something here. Any insights from the smarter minds? Please?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on February 26, 2014, 07:33:06 AM
Slight schematic update:

(http://i1277.photobucket.com/albums/y492/drolobucket/TWINPEAKStremoloschematics_zps4641a0b2.png)

Added a different voltage regulator for the LED driver section.
When I drew the schematics, I had not realized 7808's did not exist, and even if they did, there would not be enough headroom for the regulator to operate with a 9V supply.

Using a 7806 and juicing the voltage up with a LED gives enough headroom for the 5532 not to clip the PWM signal.

Also increased C5 in the highpass and reduced R18 for a less harsh treble. Sounds rounder now :-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Koopa on April 03, 2014, 02:17:33 AM
This is easily THE BEST tremolo pedal I've heard! Creative work!

I've been wondering if this has gone commercial already or is this stuff free to be used if I build my own copy of this design? I'm new to this site and this DIY-pedal stuff also. But tremolo pedal is something I've wanted to do for a while and then I found this! Amazing..

Is it ok if I (try to) build my own COPY of this? If yes..in that case I would have a couple of questions about this circuit.

1) In some schematic resistor R27 3M5 was missing. I assume that this last posted schematic is the updated one?
2) Will it work if I go with the last schematic you've posted? There was some discussion about the regulators and I am kind of confused right now how to make it. You said you didn't use them at all? So what would be the right way to do the connections?
3) I guess this is kind of a dumb question but I'm new to this stuff so nothing is obvious for me yet :D You didn't draw the bypass switch here at all. I guess that it is so obvious to everybody how to do it (except for me) that you didn't even draw it here? :P Just regular bypass option before 'IN', is that correct?
4) You said that there was some humming and then you used protected cable somewhere to get rid of that sound. Which part exactly you protected with grounded wire?
5) Ground of Input and Output cables to the same potential of battery minus? Or do you just connect the grounds from input and output and leave the battery minus independent and separate?
6) About components: Do I have to worry about the sensitivity of the components (Max voltages, etc..)? That XTAL component..what is it? I found 4 LEDS from the circuit. 1.8 V all of them? Is the indicator which tells if the tremolo is on/off separate from these schematics? I guess it goes to the bypass circuit.
7) According to those six questions, should I even try? :D


Thanks in advance!

Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on April 03, 2014, 03:54:15 AM
>  I've been wondering if this has gone commercial already or is this stuff free to be used if I build my own copy of this design? I'm new to this site and this DIY-pedal stuff also. >  But tremolo pedal is something I've wanted to do for a while and then I found this! Amazing..

>  Is it ok if I (try to) build my own COPY of this? If yes..in that case I would have a couple of questions about this circuit.

You are free to use it for non-commercial purposes.

> 1) In some schematic resistor R27 3M5 was missing. I assume that this last posted schematic is the updated one?

Not sure where you saw that resistor, but indeed the schematic posted last is the most recent one.

> 2) Will it work if I go with the last schematic you've posted? There was some discussion about the regulators and I am kind of confused right now how to make it. You said you didn't use them at all? So what would be the right way to do the connections?

The method iin the last schematic works very well.

> 3) I guess this is kind of a dumb question but I'm new to this stuff so nothing is obvious for me yet :D You didn't draw the bypass switch here at all. I guess that it is so obvious to everybody how to do it (except for me) that you didn't even draw it here? :P Just regular bypass option before 'IN', is that correct?

That's correct. If you are new to this I invite you to have a look at the beginners corner for a good start. lots of good info on the basics:

http://diystompboxes.com/wiki/index.php?title=Main_Page

http://www.diystompboxes.com/smfforum/index.php?board=10.0

> 4) You said that there was some humming and then you used protected cable somewhere to get rid of that sound. Which part exactly you protected with grounded wire?

Actually I have been building these without shielded wire and have no issues. I got this noise while testing a board outside a box with long flying leeds.

> 5) Ground of Input and Output cables to the same potential of battery minus? Or do you just connect the grounds from input and output and leave the battery minus independent and separate?

What you really need to do is keep the grounds from the audio circuit and those from the microprocessor and the led drivers separate. Only joining at one ccommon ground, at the power supply for example.

> 6) About components: Do I have to worry about the sensitivity of the components (Max voltages, etc..)? That XTAL component..what is it? I found 4 LEDS from the circuit. 1.8 V all of them? Is the indicator which tells if the tremolo is on/off separate from these schematics? I guess it goes to the bypass circuit.

Since it is to be operated at 9V I would use components that are rated at 15V at least.
Xtal stands for Crystal, in this case a 20MHz one (forgot to specify) It's a reference clock for the microprocessor.
D3 and D4 are the LEDs contained in the vactrols. The other ones can be whatever you like. Perhaps use a superbright for D2 to have less current spikes and less danger of ticking.
The bypass indicator is indeed not shown in the schematic, same with the bypass.

> 7) According to those six questions, should I even try? :D

Worst thing that can happen is that it does not work  ;-)
Perhaps if you are uncertain, try to start with something a bit easier, like a booster or an overdrive, at least to get used to the basics.

Good luck and fun in your endeavors :-)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Koopa on April 03, 2014, 04:35:16 AM
Thank you for your quick response! :)

Those really answered all my questions..Perhaps I'll start with a Keeley compressor first :P And definitely will look for those links you posted.

You should really commercialize this! MadProfessor? Boss?

And yes, no intentions to sell your design anywhere :) 
Let's keep this hipster before it goes down the mainstream.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Neur0 on January 12, 2015, 07:55:03 AM
Hello,

Digging up an "old" but great thread.
I had the Tremulus Lune on my list for building and it would be by far the most ambitious build  to date for me. That is until I came across this little gem :)
David, on your website you show a gut shot with a double sided PCB which was discussed earlier. Are they available for purchase from you or anyone else?
It would take me quite some time to design one myself with DipTrace, not to mention far worse than what you probaly have :)

Kind regards,
Remy van Noorden
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: drolo on January 12, 2015, 08:10:35 AM
Hello,

Digging up an "old" but great thread.
I had the Tremulus Lune on my list for building and it would be by far the most ambitious build  to date for me. That is until I came across this little gem :)
David, on your website you show a gut shot with a double sided PCB which was discussed earlier. Are they available for purchase from you or anyone else?
It would take me quite some time to design one myself with DipTrace, not to mention far worse than what you probaly have :)

Kind regards,
Remy van Noorden
Yes I have some PCB's available. I have sent you a PM
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: Neur0 on January 12, 2015, 09:35:06 AM
All done and sorted.

Thank you very much, David  :icon_biggrin:
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: MAndrews on July 14, 2015, 04:17:04 AM
Hi David. Been watching the demo of your tremolo and it sound wonderful - gave me goosebumps! I know it is a long time since anyone posted in this thread but I wondered if you still had any PCBs.

Thanks.

Mark.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: soderstrom on July 14, 2015, 06:04:02 AM
Hi David. Been watching the demo of your tremolo and it sound wonderful - gave me goosebumps! I know it is a long time since anyone posted in this thread but I wondered if you still had any PCBs.

Thanks.

Mark.


Hi David, same question here. I would love to build this wonderful pedal! regards

PS: OMG, my first post here! Hello!  :icon_mrgreen:
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: bnashville on November 27, 2015, 02:23:53 PM
Anyone who has built this - can you estimate what you spent on parts? I'm looking for a tap tremolo and would love to build it, but if the cost and time will exceed that of a commercially available pedal, I might go that route. To that same end, @drolo, do you still have PCBs available?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: chuckd666 on November 27, 2015, 08:12:45 PM
Vactrols are around $10 each (depending on the source I suppose), buying a pre programmed TAPLFO will probably set you back a similar amount, and all the other miscellaneous parts probably another $25-35 depending on enclosures etc. Add more for shipping! I dunno. I think in Australian dollars by the way.  ;)

I'm not sure if it's easy to find any decent tap tempo tremolos, so if you're experienced with DIY, I'd give this a go. If you're a newbie though, I'd begin with simpler circuits. That said, if you can source one of Rolo's excellent PCBs it might be doable for you.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: dbp512 on November 27, 2015, 08:38:37 PM
I priced it out recently and it looks like it would cost about $50 plus shipping and an enclosure. The vactrols and taplfo chip are from smallbear, and the rest for tayda. If you wait for one of their monthly sales you could save a bit. I want to build this and a liquid mercury (I don't look forward to that on vero). I'm really hoping I can get pcb's for these.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: bnashville on November 27, 2015, 10:40:01 PM
Thanks for the quick replies. It sounds like this would be a great project for a pretty reasonable price if I can track down a pcb or layout file. I know enough to follow a schematic pretty well, but not enough to make too many changes - does anyone know what it would take to make this stereo?
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: dbp512 on November 28, 2015, 12:11:43 PM
Tagboard has a veroboard layout of this. As for converting it to stereo, I can't help.


http://tagboardeffects.blogspot.com/2015/10/twin-peaks-tap-tempo-tremolo.html (http://tagboardeffects.blogspot.com/2015/10/twin-peaks-tap-tempo-tremolo.html)
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: abakuzam on April 24, 2016, 08:47:14 AM
Anyone selling pcbs? Or is there any transfer picture for this beauty? cheers.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: dbp512 on April 24, 2016, 12:25:52 PM
Anyone selling pcbs? Or is there any transfer picture for this beauty? cheers.

Message Drolo (who created the circuit), he's running a group buy for several of his designs.
Title: Re: TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)
Post by: abakuzam on April 24, 2016, 04:35:59 PM
Anyone selling pcbs? Or is there any transfer picture for this beauty? cheers.

Message Drolo (who created the circuit), he's running a group buy for several of his designs.
Thanks, i contacted with him:)