Inspired by the Valve Caster

[panterica]

I'm new here (only build so far has been a bass rocket fuzz), and I've just read the forty-something pages about the Valve Caster/Twin Caster builds and mods. I love the warm bluesy overdrive these pedals are capable of, but it's just not what I'm looking for... though I do think I will build a Twin Caster with a PentaBoost for bass guitar soon enough.

Anyway, what I'm really after is the idea of a low voltage tube-based distortion with a sound much like the Dr. Boogey. Has anyone attempted a pedal like this yet?

[Renegadrian]

welcome - not yet but you can bet we are at work!!! join us with your breadboard!!!

[panterica]

Thank you! I surely will!

[runmikeyrun]

Once i get my mods for bass valvecaster set straight i'll post them.  Had to change a few bits since my active bass was overloading the input. 

[Jered]

Anyway, what I'm really after is the idea of a low voltage tube-based distortion with a sound much like the Dr. Boogey. Has anyone attempted a pedal like this yet?

   This will get you there and then some.

[panterica]

Sweet!

I can't help but ask: Do you have any sound clips? Have you tried any other tubes, like the 6111?

[Jered]

  No sound clips, but if you like the Recto red chan/Soldano high gain type sound you should be pleased. Yes it works with 6111 without ant tweaks, but of course, try different things to fine tune it to your liking. 6112's will also work with some minor tweaks.

[panterica]

  No sound clips, but if you like the Recto red chan/Soldano high gain type sound you should be pleased. Yes it works with 6111 without ant tweaks, but of course, try different things to fine tune it to your liking. 6112's will also work with some minor tweaks.

Man, that sounds like exactly what I'm looking for. I appreciate it. Have you tried it at higher voltages than 18v?

[Jered]

  I tried it up to 60 volts. The higher voltage gives you greater head room. 18 volts is the minimum voltage at which the gain maxed starts to sound good. Below 18 volts and gain dimed it over saturates and is buzzy. Above 30 volts and your in recto heaven. Enjoy.

[Ripthorn]

What is the value of that cap to ground off the first tube?  It looks like 0.68, but I'm not certain.  I'm going to have to build one of these now...

[Jered]

  Yes, .68, common in Marshall amps.

[Ripthorn]

  I tried it up to 60 volts. The higher voltage gives you greater head room. 18 volts is the minimum voltage at which the gain maxed starts to sound good. Below 18 volts and gain dimed it over saturates and is buzzy. Above 30 volts and your in recto heaven. Enjoy.

So for the voltage, what would you think of having something like a MAX1044 (9V in) and have a switch for 18V and ~36V supply?  Would any component values need tweaking for different voltage? 

[Jered]

  I don't know I've never messed with the max1044. I was just using rectified AC voltage and no component changes were needed, but try any ideas you might have. That's what this forum is all about. Just make shure the heaters get the proper voltage and mA.

[frequencycentral]

  I tried it up to 60 volts. The higher voltage gives you greater head room. 18 volts is the minimum voltage at which the gain maxed starts to sound good. Below 18 volts and gain dimed it over saturates and is buzzy. Above 30 volts and your in recto heaven. Enjoy.

So for the voltage, what would you think of having something like a MAX1044 (9V in) and have a switch for 18V and ~36V supply?  Would any component values need tweaking for different voltage? 

MAX will do it! I've successfully powered two 6111 this way at up to ~70v. 6021 and 6111 dont differ much. Or try 7327, which is a direct replacement for both. I've breadboarded 7327 next to 6111 and they are identical, with the advantage that they can be used at much higher voltages.

http://frank.pocnet.net/sheets/138/7/7327.pdf

[Jered]

  Cool! I need to look around and see if I can locate some of those tubes.

[cox]

and what about making a low wattage amp from this one?
i would be interessed in that!!
i've seen your murder one, rick but it's kind of hard (if not impossible) getting those max ic...
and having a subminiature tube amp is on me wish list, so....
you guys can do it!!!

[frequencycentral]

i've seen your murder one, rick but it's kind of hard (if not impossible) getting those max ic...

http://www.diystompboxes.com/smfforum/index.php?topic=73759.0

[Ripthorn]

Is a chip like the TC1044 able to provide enough current to a 6111 or 6021 tube?  I looke at the ones Digikey carries and it says 20 mA output current.  Seems like that wouldn't be enough to drive four cathodes like in this project.  Then again, I have never done anything with tubes before or with 1044 chips.

[frequencycentral]

Is a chip like the TC1044 able to provide enough current to a 6111 or 6021 tube?  I looke at the ones Digikey carries and it says 20 mA output current.  Seems like that wouldn't be enough to drive four cathodes like in this project.  Then again, I have never done anything with tubes before or with 1044 chips.

Yup - it's the heaters that draw the big ma, 6.3v / 300ma for a 6111, or 12.6v / 300ma if you run the heaters in series. The plates draw very little. Trust me on this - it lives on my breadboard.

[Ripthorn]

So for this particular project, there are two tubes, each with two heaters.  Could I use something like an LM317 to provide 25.2V at 300 mA and run all four heaters in series or is that not recommended?  I am just thinking that my power supply probably wouldn't do 600 mA (only rated to 500 mA).  Also, the schematic for the dual triodes I have seen look like the heaters are connected to each other internally, is this correct?  Because then I could just run the power in to one heater and then from the pin of the second heater to the second tube.  Can I do this or am I oversimplifying the problem?