help designing and building guitar amp

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Hi, i need some help designing a guitar amp head for a cab iv'e allready built. I have never built a tube amp before but have built solid state amps before. i understand the theroy of how a tube amp works but have no idea which tubes to get hold of, what value risistors i should use, what output transformer, ect. i'm looking for about 10-15 watts into an 8ohm load. needs to have 2 preamlifiers, one for clean and one(high gain) for overdrive. i have seen a few scematics but i dont really know what tubes i should start with. i know how to wire the tone control, assumeing that i can have one stage with a line out, tone control, next stage, ect. also im not sure wether to use a solid state rectifier of tube. speaker is a 12inch celestion g12h in a sealed back cab. any ideas would be much appreciated. thanks!
 
The most common tubes for guitar amps are 12AX7 = ECC83 for the preamp part and pentodes such as EL84, EL34, 6L6GC, 6V6, depending on the power you want, for the power amplifier. These tubes are still in current production and are not that expensive if you keep an eye out.

The ax84 website mentioned by Pete is a very good starting point.

For your first tube amp I'd recommend to use a solid state rectifier, since it's a bit easier to build. This will maximize your chances of success and therefore minimize possible disappointments.

Kenneth
 
Start simple, you'll get a great tone! Remember that most guitar amp manufacturers have to make an amp that pleases the death metal musician as well as the smooth jazz musician. A hardwired amp made for you may only need one knob! In tube amps, just removing the feedback input to the pre can give a harmonics rich, grainy boost. Something simple allows you to experiment with the tones a tube can make, without getting (as) frustrated.

Some links:
http://www.freewebs.com/valvewizard/ Explains most basic guitar amp and tube amp circuits and how to design them

Fun With Tubes Explains basic tube operation, as well as explores some designs (hifi oriented, useful nonetheless!)

AX84.com - The Cooperative Tube Guitar Amp Project The aformentioned.

Remember it's easier to make a fender champ sound good (from a design/repair standpoint) than a dual showman or a mesa quintuple rectifier ultra diode kitchen sink.
 
I would have said to go with a kit for the 1st build. However, the requirement for preamp distortion on one channel, and none on the other is a small monkey wrench. Not sure if AX84 has one listed but the forum should help.

This schematic always struck me as a good foundation for such a project.

http://www.schematicheaven.com/fenderamps/bassman_6g6a_schem.pdf

Mess with the Bass channel a little. Change the treble control to the output volume for the distortion channel. Use the “volume” control of that side as the distortion control. Make the tone stack more typical and include a mid control. Normal channel is already close to a Normal channel on most BF/SF Fenders. Different plate and cathode resistors in the 2nd stage though.
 
The most common tubes for guitar amps are 12AX7 = ECC83 for the preamp part and pentodes such as EL84, EL34, 6L6GC, 6V6, depending on the power you want, for the power amplifier. These tubes are still in current production and are not that expensive if you keep an eye out.

The ax84 website mentioned by Pete is a very good starting point.

For your first tube amp I'd recommend to use a solid state rectifier, since it's a bit easier to build. This will maximize your chances of success and therefore minimize possible disappointments.

Kenneth

I was going to use a solid state rectifier because i have a load of dead smps boards from pc power supplies with 600v silicon rectifiers on them.
 
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