#1
So. I was thinking the other day, and I'm considering designing and building my own tube pedal. The only problem is that I've never really studied preamp tubes, and all I'm really familiar with is bipolar transistors. So. What would I need to know to make a tube pedal? I'm familiar with the pinout, but my main concern is the power supply and biasing of the tubes. Any help, Kerry, Drew, other holders of electronics witchcraft?
#3
^ It'll be a boost/overdrive running off (probably) a 12AT7. First and foremost it'll be a booster, then a little bit of light overdrive as the gain is turned up. It'll be an original design.

EDIT: What about the power coming into the plate? What voltage does that need to be?
Last edited by cokeisbetter at Aug 6, 2007,
#5
Oh, the footswitches was just indicating that the tubes are in a pedal, not an amp. The idea is a tube boost/OD. Did you see my edit above?
#7
Check out the Shaka Tube or Chandler Tube Driver. I've heard lots of good things about the Shaka tube, it's apparently got a lot more useable gain than the Tube Driver. Pretty easy build too, PCB designs are available on the net.
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."
#8
^ I want to build my own pedal, though, not use a design that's already out there. I've already got a basic idea of what I'll do with it in my head.
#9
Quote by cokeisbetter
^ I want to build my own pedal, though, not use a design that's already out there. I've already got a basic idea of what I'll do with it in my head.


Do you know a lot about tubes? Could be an idea to just take a pre-amp off an existing amp and run off a power supply similar to the Real McTube.
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."
#11
^-The Fetzer Valve is a boost to simulate a tube, but its not tube itself. It shows you converting the Fender amp's input to be able to be used with a J201.
#12
Emulating tubes with JFETs is a reasonable way to go. They won't sound exactly like tubes, but they are a helluva lot easier to work with. Lower voltage, no heater supply, no heat dissipation issues in the chassis, etc.

If you are still convinced you want to do a tube pedal, I'd avoid the 12AT7, as they tend to have more problems with microphonics. Using one so early in the signal chain, means you will have to do a lot of sorting to find quiet ones. A better choice would be a 12AX7 or a 7025.

To learn more about tube basics, try this site. Just skip the parts on radio, and read the parts on audio. This old-timer has put together a great (imho) primer for anyone interested in learning about tubes.
http://www.angelfire.com/electronic/funwithtubes/

If it's a distortion pedal you're looking to build, you will definitely want to experiment with the sizes of the plate resistor and the cathode resistor to bias the tube closer to saturation or cut-off, depending on if you want the distortion to be smoother or more "edgy".

Good luck,
SYK
Meadows
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