Tube boost + overdrive running off a 9 volt battery

[FlyingZ]

Great clips, I love the way the ValveCaster doesn't change the original tone like I'm discovering so many DIY projects do. I really hope to find another good one soon 
Two breadboard projects (BluesBreaker and CK721 ToneBender) to finish testing and I will submit a ValveCaster clip.

[Franky]

Hi guys, first message here..

I read all this thread many times, there are a lot of great tube projects, and I decided to make my own.

I'd like to thank you for gathering all the "mods" on one post, that is very usefull...


The idea is to make an overdrive pedal out of a Twincaster, and be able to go from barely clean sounds to huge amounts of OD gain (using a 12AY7 tube, which someone told me it was more adapted for OD).

I know that I'm gonna have to breadboard a lot before getting satisfied, but the modslist should help a lot..

[Renegadrian]

Hello and welcome aboard - I am sure your work will be appreciated. Looking forward to see your results!

[Franky]

Thank you Adriano, but I'm still a bit confused about something..

In the mods list, we have both version of the gain pot:

"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."

Which means that the higher the pot value (and thereby the cathode resistor value), the higher the gain.

But there's also this:

"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."

Which one is the right one? 

[frequencycentral]

"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."

Which one is the right one? 

The first one is wrong - the triode is at its loudest with the cathode hooked directly to ground. I prefer a 100K gain pot, as this will increase clean headroom.

Everything in the second quote is correct.

[Franky]

Thank you Rick!

Okay, I planned my design using a "More Gain" switch, which would have done exactly the contrary as expected if I had followed the first quote's instructions.. 


Well, to get more gain the only solution would be to put a switch to increase the plate resistors? I thought about putting a 100k resistor in series with 2nd and 4th triodes' plate resistors (making a 200k equivalent plate resistor).
What do you think about it?

I also noticed that someone here used a 2.2nF bypass cap across the gain pot, to "keep some brightness" when the gain is down. Good idea too..

[frequencycentral]

Well, to get more gain the only solution would be to put a switch to increase the plate resistors?

..........or make ALL the plate resistors into pots for a multi knob Evilcaster!!!

[Franky]

Wow, don't tempt me.. 


Here's my schematic. So far, it's a beta version: (also available in PDF format, here)





There is also one thing not to forget: pots don't like the DC current. It would be better for their lifetime to feed them AC signal, and mount them as volume pots. Between 2 VC for example, or as in old Marshall preamps, after the first triode.

[Renegadrian]

Seems a great circuit...Did you build it yet or it's just a schem?

[slacker]

Looks cool

I'd change the classic/more gain switch so that the 2 resistors (R4, R5) are permanently connected and use the switch to short one of them out. The way you've got it when you flip the switch you'll momentarily break the connection to the plates which might lead to pops and other nasty noises.

[Franky]

@ Adriano: No it's only a schemo, I don't have the parts yet, but when it's the case, I spend some time on the breadboard to make it sound as I want..

@ Slacker: damn you're right, I thought about popping, but this solution was something I didn't think about.. Thank you!


I still don't know whether I put some caps across the gain pots or not.. Anyway there are a lot of values possible, 2.2nF was written on the summup..


Edit: it's updated.. 

[kurtlives]

On my dual Valve Caster I am using a dual gang 100K B pot. Controls both gains..

[Franky]

that's incredible all these little tubes can make.. (speaking about the Vibrocaster), I'm sure it's possible to design a tube wah.. A Wahlvecaster?

[cheeb]

You can't think of anything that R.G. hasn't done.
http://geofex.com/article_folders/tube-wah/tube-wah.htm

[FlyingZ]

Here is my plain 12v ValveCaster clip:
http://www.aronnelson.com/gallery/main.php/v/FlyingZ/ValveCaster.mp3.html?g2

[tranceracer]

Very nice clips!  I like how you have your ValveCaster sounds with different tones.  I think I'll have to redo my samples!   

-bK

[mth5044]

Wow, I started reading that about three hours ago. Read, digested and puked it all back up again. Man that's a lot of good stuff. Around page 27, I just started scrolling through to look at the pictures because some of them are very lovely. I went to the layout section of this site to look for some of the board stuff, but only could find dano's original. I'm not sure if there is a verified section of layouts, mods, parts and stuff, but if there isn't, that could be a good thing to have.

I also think I'm going to have to try and put one of these together. I really liked the one that used two 12au7 tubes. I was thinking about making them more kind of like two pedals in one instead of one pedal. One footswitch would turn one on and another switch to activiate the next tube for more gain. I would like to only have 2 gains, one volume and one tone. Is that possible with this kind of setup? Then I also read in there somewhere that having a booster in there is a good idea too. So where is the best place for that to go? I was thinking of putting in a stratoblaster because the LB1 or 2 were said to be too muddy. Maybe even a stratoblaster before and after the circuit? Sheesh.

Also, I've only dealt with building a guytronix tube amp and a bunch of pedals, but they dont use 12v adapters. Where can I get one of these that good but also not very expensive, as I am poor.

Thanks  and sorry if this was all discussed. My mind is fried from the rest of this thread to comprehend the last few pages.

[Renegadrian]

quote author=mth5044
I went to the layout section of this site to look for some of the board stuff, but only could find dano's original. I'm not sure if there is a verified section of layouts, mods, parts and stuff, but if there isn't, that could be a good thing to have.
STRANGE, DID YOU SEARCH FOR VALVECASTER? TYPE IT, YOU WILL FIND MY VERO LAYOUTS. OR YOU CAN SEARCH MY FOLDER IT'S AT THE LAST PAGES.


I also think I'm going to have to try and put one of these together. I really liked the one that used two 12au7 tubes. I was thinking about making them more kind of like two pedals in one instead of one pedal. One footswitch would turn one on and another switch to activiate the next tube for more gain. I would like to only have 2 gains, one volume and one tone. Is that possible with this kind of setup? Then I also read in there somewhere that having a booster in there is a good idea too. So where is the best place for that to go? I was thinking of putting in a stratoblaster because the LB1 or 2 were said to be too muddy. Maybe even a stratoblaster before and after the circuit? Sheesh.
NOT A CRAZY IDEA, THAT COULD BE DONE...AND YES A BOOSTER BEFORE THE TUBE COULD SPICE THINGS UP...I'D SAY TILLMAN OR STRATOBLASTER TOO...BUT AS A BOOSTER IS SO EASY TO BUILD (I HAVE SEVERAL JUST TO TRY THEM...)  I'D SAY BUILD THE ONES YOU WANT AND TRY THEM ALL...


Also, I've only dealt with building a guytronix tube amp and a bunch of pedals, but they dont use 12v adapters. Where can I get one of these that good but also not very expensive, as I am poor.
I USE A €5 ONE AND A €7 ONE - CHINESE MADE - THEY DO THE JOB AND WON'T BREAK FINANCES...


Thanks  and sorry if this was all discussed. My mind is fried from the rest of this thread to comprehend the last few pages.
I BELIEVE YOU'LL BE SAYIN' "HOW THE HELL CAN SUCH A SIMPLE CIRCUIT BRING OUT THESE SOUNDS!!!!" - ACTUALLY I DID...

[tranceracer]

Wow, I started reading that about three hours ago. Read, digested and puked it all back up again. Man that's a lot of good stuff. Around page 27, I just started scrolling through to look at the pictures because some of them are very lovely. I went to the layout section of this site to look for some of the board stuff, but only could find dano's original. I'm not sure if there is a verified section of layouts, mods, parts and stuff, but if there isn't, that could be a good thing to have.

I also think I'm going to have to try and put one of these together. I really liked the one that used two 12au7 tubes. I was thinking about making them more kind of like two pedals in one instead of one pedal. One footswitch would turn one on and another switch to activiate the next tube for more gain. I would like to only have 2 gains, one volume and one tone. Is that possible with this kind of setup? Then I also read in there somewhere that having a booster in there is a good idea too. So where is the best place for that to go? I was thinking of putting in a stratoblaster because the LB1 or 2 were said to be too muddy. Maybe even a stratoblaster before and after the circuit? Sheesh.

Also, I've only dealt with building a guytronix tube amp and a bunch of pedals, but they dont use 12v adapters. Where can I get one of these that good but also not very expensive, as I am poor.

Thanks  and sorry if this was all discussed. My mind is fried from the rest of this thread to comprehend the last few pages.

Here's a summary of some of the topics that inspired me to build this. 
http://www.aronnelson.com/DIYFiles/up/12AU7-6111_Valve_Caster_Summary.pdf

Renegadrian's vero has been tested and known to work.  I also posted a PCB (but IMHO, a lot of extra work for such a small ckt. )

Send us pics of your 'caster when you're done.   

[snap]

Wow, I started reading that about three hours ago. Read, digested and puked it all back up again. Man that's a lot of good stuff. Around page 27, I just started scrolling through to look at the pictures because some of them are very lovely. I went to the layout section of this site to look for some of the board stuff, but only could find dano's original. I'm not sure if there is a verified section of layouts, mods, parts and stuff, but if there isn't, that could be a good thing to have.

I also think I'm going to have to try and put one of these together. I really liked the one that used two 12au7 tubes. I was thinking about making them more kind of like two pedals in one instead of one pedal. One footswitch would turn one on and another switch to activiate the next tube for more gain. I would like to only have 2 gains, one volume and one tone. Is that possible with this kind of setup? Then I also read in there somewhere that having a booster in there is a good idea too. So where is the best place for that to go? I was thinking of putting in a stratoblaster because the LB1 or 2 were said to be too muddy. Maybe even a stratoblaster before and after the circuit? Sheesh.

Also, I've only dealt with building a guytronix tube amp and a bunch of pedals, but they dont use 12v adapters. Where can I get one of these that good but also not very expensive, as I am poor.

Thanks  and sorry if this was all discussed. My mind is fried from the rest of this thread to comprehend the last few pages.

Here's a summary of some of the topics that inspired me to build this. 
http://www.aronnelson.com/DIYFiles/up/12AU7-6111_Valve_Caster_Summary.pdf

Renegadrian's vero has been tested and known to work.  I also posted a PCB (but IMHO, a lot of extra work for such a small ckt. )

Send us pics of your 'caster when you're done.   

In that summary on page 4 the Dual Valve Casters schematic 3. triode still missing a gridleak resistor.
http://www.diystompboxes.com/smfforum/index.php?topic=68759.0