Tube boost + overdrive running off a 9 volt battery

[rugeb]

Rotary switch for input tone control:

[texstrat]

The heater voltage is not critical. My veroboard is VERIFIED: copy!
Another power supply (12V amp with 12AU7 + JRC386):

Sound clips??

[mwynwood]

Hi guys - I finished my Valvecaster and it sounds great Thanks!
I removed the Tone control, so it's just Gain and Volume.
Here are some sound-clips, if anyone is interested: http://soundcloud.com/mwynwood/my-valve-overdrive-pedal

[Isak]

Hello guys

i came a cross this cool project and i have some questions..

1 - can i use any 12AU7 TUBE? for example... can i use this one : http://www.ebay.com/itm/2x-NEW-JJ-Tesla-12AU7-ECC82-Vacuum-Tubes-Matched-Pair-TESTED-/290626797687?pt=Vintage_Electronics_R2&hash=item43aab50077#ht_1127wt_1164
or... this : http://www.ebay.com/itm/TUBE-AMP-PREAMP-DAMPERS-12AX7-12AU7-12AT7-ECC83-EL84-6922-EL84-5751-5687-/350539278417?pt=Vintage_Electronics_R2&hash=item519dc4e851#ht_4357wt_1397
sorry for the noob question, i dont know or understand in tubes..  

2 - does any of you guys maybe connect the Valve Caster to a synth? (i want it more for synth )

3 - does this circuit can run on 12V DC without changing anything?

4 - does the TUBE lighted up  


thanks in advance  
Sincerely,
Isak E.

[Renegadrian]

1) first link is for 2 coupled tubes, second link is for the ring dampers. You don't need ring dampers, you need one tube.
2) Not that I know. But it can be used at the place of your ordinary preamp if you use one.
3) Read the whole thread
4) Read the whole thread

[Isak]

thank you for your reply friend

1 i didnt see that the second link is ring dampers, sorry about that.
2 so it can be use as a preamp haaa...?
3 - 4 excuse me sir, why i need to read the whole thread (141 pages, just a reminder) if you know the answer? i'm sure you probable answered this questions a 10000000 times, but hey....you are here for this purpose, or i'm wrong?
i think the whole idea behind a forum is to help people.

i'm sorry if i bothered you with my questions.
i will not ask again and no hard feelings.

Sincerely,
Isak E.

[Pollinator95]

I read this thread a while ago (when it was about 130 pages) so my memory isn't perfect, but I think the answers are: it depends. The circuit should work on 12V, just make sure the caps are rated at least at 24V. And if the tube doesn't light up enough, stick a LED in the socket. Most answers are in the first few pages, I think.
Renegadrian is a great guy and he's always helpful but, as you say, he's answered 10000000 times.

Edit: glow: post #12; 12V: just about everywhere (yes, it works).

[Isak]

Pollinator95 thank you for replying.

i know he is a great guy, i "read" almost half way and see how he helped people, but man 141 pages!?!?!?!?!?!?
in any way i will never do that to no one even if i answered million times, if the thread is long as the universe of course.
i dont have nothing against him he actually helped me even without him knowing that and i thank him for that!!!

i hope it will sound good with synth's 

Renegadrian...thank you!

Pollinator95 thank you again.
 
Sincerely,
Isak E.

[rugeb]

Hi guys - I finished my Valvecaster and it sounds great Thanks!
I removed the Tone control, so it's just Gain and Volume.
Here are some sound-clips, if anyone is interested: http://soundcloud.com/mwynwood/my-valve-overdrive-pedal

*****************************
= VERY  COOL - CONGRATULATIONS! =
*****************************

[juansolo]

Don't get JJ 12au7 tubes for a 12v valvecaster, they don't work very well at low voltages.

[Isak]

Don't get JJ 12au7 tubes for a 12v valvecaster, they don't work very well at low voltages.

thank you for pointing this out, what do you suggest?

[texstrat]

Pollinator95 thank you for replying.

i know he is a great guy, i "read" almost half way and see how he helped people, but man 141 pages!?!?!?!?!?!?
in any way i will never do that to no one even if i answered million times, if the thread is long as the universe of course.
i dont have nothing against him he actually helped me even without him knowing that and i thank him for that!!!

i hope it will sound good with synth's 

Renegadrian...thank you!

Pollinator95 thank you again.
 
Sincerely,
Isak E.

Isak:

It took me a week to read all 140 pages, but I came away with a wealth of information and knowledge about this little project. The search function can and is your friend. Also the high points of this single tube VC has been summarized in pdf form by one of the members, there are two of them, make sure you download the second as a couple of errors were corrected with the second version.

Another suggestion would be to create a word document and cut/paste pertinent information, such as mods and any information related to using a 12V power supply.

Most if not all your questions will be answered in this thread.

I would recommend building the single valve with/without the Tone pot first before attempting the dual tube build. You also have the option of building the VC with all the major components soldered directly on the tube socket, which I did, or on vero board.

Good luck and happy building.

[Isak]

texstrat

thank you, this is what i'm trying to do now im on page 57 
and i still dont know what tube to order from ebay...
they have a lot.
what tube did you used?

[texstrat]

texstrat

thank you, this is what i'm trying to do now im on page 57 
and i still dont know what tube to order from ebay...
they have a lot.
what tube did you used?

I did not see anything on page 57, but this is the schematic I used and it does work.



I used a generic 12V 700mA power supply. Anything rated over 200mA will be fine. Make sure to switch the power tip so that the outer sleeve is (+) and the inner part of the barrel is (-). Is is also important to include a voltage regulator on the DC jack; otherwise, you will get a lot of hum.

The switch that is drawn in allows you to cut the bass, it acts like a boost.

As to tubes, I like the way the 12ua7a, 12ax7 and 12at7 work. Each gives the effect a distinctly different tone. Here is a quote from another member about the different tubes @12V
"12ax7 no real gain.. ok.. but no boost..
12au7 good boost, when gain maxed really farts out.
12u7 -- good sounding, mod gain, no difference adding more voltage.
12at7 -- more distortion (good in my eyes)
ECC99 .. my GOD... best sounding for me.. Good distortion, turn down to "warm" overdrive.. lots of boost, would not turn master volume past 1/4
5751 -- Good sounding low boost, nice warm overdrive but bad when gain turned more than 75%"

One note about the attached image, pin 3 (Vout) on the 7812 voltage regulator does not go to lug 4 of the foot switch. Remove the two wire leads from the DC jack and solder those to pin 3.

I also took C1 going to pin 2 of the tube and in place put a on-on DPDT switch in to try different capacitor values. I play both single coil and humbucker guitars and found that a 0.1uf cap works better with the single coil and the 0.22uf sounds better with the humbuckers.

Hope this helps.

[Jdansti]

I just finished reading all 141 pages AND finishing my Valvecaster!  It is a mostly stock 12AU7 unit running @ 12V, 4 position cap selector on the input, 2.2nf cap across the gain pot, a switch to exclude the tone circuit, and a trim pot substituting for R2.  I adjusted the trim to give a clean boost at low volume and minimum gain. I get a nice overdrive by turning up the volume and gain pots. Thanks to all of you folks for the massive wealth of information on this thread!

[Isak]

thanks for the info texstrat .

i meant that i'm reading on page 57 and keep on reading now on page 86
i'm actually looking for the bass sound
i'm not a guitar player, i'm a synthesizer/keyboards player.
i'm assembling an analog filter (korg ms20 based) and i wanted to put on the audio path an overdrive to get warm bassy sound after the filter.
then i searched the net for overdrives and i came a cross this amazing tube based overdrive.
i found on tube this cool vid of the valvecaster vs x0xb0x http://www.youtube.com/watch?v=wITCU1xOFMI
i dont want the sound to be boosty only to give it character (sound reasonable?)
i guess i will need to to run some tests after assembling the valvecaster.

any of you guys maybe have an analog synth and can tell me how its sounds after connecting the valvecaster to the synth?

cheers,
Isak E.

[Renegadrian]

3)while the title of this topic says it runs on a 9v battery, it is almost mandatory to use a wall wart (heaters do suck lots of current) and run on 12V to follow the heaters specs (it should be 12.6V but it's ok at 12V) - basically you can wire it in two different ways, 12V feeding the whole circuit or 12V to heaters and more V to the plates
4) every tube is different, it goes from a barely lit spark to a nice orange glow.

Isak, didn't want to be rude, yeah I answered to the same questions more than once, but it's ok every time.
Meanwhile your questions got answers, it is strongly suggested to read everything on the topic, as texstrat points out.
I know it takes time, but it will give you more knowledge about it.
Else, just take the layout from beano at the very first page of the topic and go thru - it'll work just the same!

[Isak]

hi Renegadrian.

thank you for everything.
i think you should summery all the important things of this cool project to one post, dont you think?
some one did it a long the way of this endless thread ..

the next quote and everything on page 141 is more then enough for the project. 

Possible improvement, depending on context:


"I note that the original schematic and layout specify that the triode at pins 1-3 be used for the voltage gain stage, and 6-8 for the follower.

This isn't usually the best way to do it with a 12A*7.  With battery power or regulated DC going through the heaters, it doesn't matter which triode you use in which position, but if you're using AC or less-than-pristine DC, the triode at pins 6-8 will be quieter, due to the location of the heater pins on the tube.  (You can find mention of this in the data sheets on many 12A*7 series tubes.)"



"I lower the coupling cap between stages for less bass."



"For lowering bass, you could try lowering the value of either the input cap, or the coupling cap between the two tube stages."



"I am bypassing the Valvecaster gain pot with a 2.2nf cap. This helps maintain some brightness when the VC gain is turned down. For the input cap on the Valvecaster I am using a combination of caps to give me 2.7nf. This helps tighten up the bottom end."



"To tame the gain I would lower R2 and R3. 220k and 100k seem pretty high for a low voltage circuit. Even in a regular high voltage amp the normal value is just 100k. So maybe cut them in half."



"if you bring down that 220k to 100k it will def lower the gain a bit.  I built mine with both plate r's at 100k."



"A 1M gain pot allows massive, saturated gain. A little mushy in the bass frequencies, but pretty cool. I'm considering putting a "more" switch in, whereby it adds a resistor in series to the regular gain pot."



"Adding resistance to the plate resistors(R1 and R2) will increase gain. Adding resisitance to VR1, in series with the gain pot, will decrease gain."



"guitarx: replace the 100k resistor with 47k. Replace the 220k resistor with 100k. Beautiful cleans."

   

"To fellow Valvecaster experimenters -- I've currently got this circuit on a breadboard, switching out everything and I have some items of interest to report, especially for those looking for more gain.

The nicest clean sound I've found so far, is with the following mods:
R2 = 100k
R3 = 47k
C1 = 0.1uf
Remove C4 and VR2"


ecc82 electro harmonix = perfect sound as expected
ecc82 electro harmonix gold pin = less gain
gt 12ax7a = bad
sovtek 12ax7 = bad
gt 12ax7wc = little overdrive and gain but good sound
vintage ei yugoslavia 12ax7 = lots of gain and harmonics

put a 100uF cap across the DC jack (positive leg to positive rail, neg. leg to neg. rail), then, instead of connecting the positive rail directly to the circuit, connect it to the regulator's pin1, ground to pin2, and the circuit to pin3. Then screw it on the enclosure. It is a 7812.

do yaa have anything to add?


anyway...
wanted to ask please...
can you recommend/advice me on what brand of caps to use for this project?
if you have a link for me to order from it will be great.

I WANT TO START THIS PROJECT VERY MUCH!!!! 

thank again
Isak E.

[tasos]

Rotary switch for input tone control:

Hey...
good one however i thought that the 68k resistor that the signal of a passive instrument faces drops the volume right?
Won't this lead to less gain?
I mean the ''stock'' circuit doesn't have that resistor.

[rugeb]

Renegradian wrote: 12v for heaters or 12,6v... is true! but is not critical, heaters and plates on 9v works well with 12AU7 tube.
My veroboard (pg.140) it's verified, assembled and tested at 9v: the sound is very nice.