Amp build help, recommendations and advice needed.

[zowno]

Hi all, I am new to the forums and am in need of help. I'm just about to sell an old amp of mine and I'm considering building an amp to replace it. I am relatively understanding of electronics and both of my parents are very experienced. I wanted to do a 20 watt amp that has nice cleans and interacts with a guitar volume control.

I have settled on the AX84 Clean preamp mated to the single ended 20 watt power amp. I have a couple of mods and questions about this if you can help. I would like to include a switchable boost circuit. Possibly the SHO boost pedal. What do I need to do to change the pot into a fixed circuit and am I able to run the circuit of the amps power source. I was wondering as well if there are any interesting things that could be done to the tone stack, I want a fairly voxish sound. I was hoping to include a switch to bypass the master volume if possible. Finally I want to put this all into a combo enclosure with a 12" 50W RMS 8/16 ohm speaker, would this be suitable?

Is this or any of this possible and what tips can you give me. Either of my parents can help me debug the schematics and components, but I need help to get this idea together. Thank you all!

[xtian]

Welcome, hi, howdy.

The ax84 web site is great for first timers. They have some great projects that are very clearly detailed in schematics and layouts, and a lot of nice people to help, too.

Your comment "clean" / "but reacts to guitar's volume control" is confusing. You'll want a preamp that can generate some distortion in order to take advantage of your guitar's volume knob to go from clean to mean.

I hate to put any solid state distortion in the amps I build, though I use plenty of pedals. You should probably keep your design simple, and close to the schematic you choose--this stuff gets complicated really fast when you try to shoehorn stuff together.

[Stevem]

So is it that you want the sound of a vox single ended amp like a 5 watt Vox, cause to get 20 watts single ended you will need to run parallel EL84s, or go with a push pull class A output stage like a Vox 15 watt amp?
For a lot of folks the preamp sound of a Vox amp is all about the Pentode type preamp tube that was used and not the normal 12AX7 triode type.
There is tons of mods that can be done to most any preamp circuit, at least ones with a bass and treble control and to aid in your checking them out, I would build the preamp section by means of solder type terminal strips first until you get settled on something.
With the use of the right master volume set up there will be no need for a bypass switch, as when the control is full up it will be out of the circuit.