Building a Solid State Amp. Really?

printer2

Poster Extraordinaire
Joined
May 24, 2010
Posts
8,281
Location
Canada
You can find the SS Guitar Amplifier book at the SS Amplifier forum site:


There’s a wealth of info and discussions about building and repairing solid state guitar amps.

Regarding the role of the power amp (and speaker+cabinet) most suggest that the preamp should provide all of the overdrive and simulated tube tones (if desired) and the power amp will just amplify that signal so that it can replicated through your speaker at a suitable volume. Most chip-based amps do this, for example the Vox Pathfinder, which uses a TDA2030 to cleanly amplify the preamp output. Generally, this arrangement is desirable since chip amps clip in a nasty way and that clipping should be prevented. The Roland BC-30 is one of the only amps I’ve seen that tries to soft clip a chip-based power amp to avoid that clipping and perhaps provide a unique response to large amplitude inputs from the preamp stage. I’ve done some simulations in Spice that suggest it should work and at some point I’ll have a go at fooling around with this on my breadboard.
Have the book, anybody that want's to go to the SS route would be advised to get it. This amp will not be anything special circuit wise. The amp section will easily overdrive the speaker, at least I will put in a couple of clipping diodesto clip the signal before the amplifier section does. It most likely will have some in the preamp section also. A Mk II model will probably go further, I only have so much room on the front panel with this one. Scrounging parts for this one, glad I did not recycle a couple of electronic boards, I do not have many low voltage capacitors or 1/4W resistors. I plan on making the power amp section first and mount it then use it for my testing. I have one idea to get some current feedback, not sure how it will work yet, might just make a power oscillator.
 

printer2

Poster Extraordinaire
Joined
May 24, 2010
Posts
8,281
Location
Canada
I have been working on this in between other projects. I had the speaker sitting on top of the bracing for it but with the extended thickness gasket it would cause the grill to stick out farther than I liked. Two steps forward, one back, I stuck in some filler pieces and I will be mounting the speaker from the inside. Will be a pain but I do it to myself all the time. I am not going with the linear power amplifier, thinking ahead for battery operation, a class D amp is more efficient. I put it and a breadboard on a chassis I will be using for another tube amp (the board is already assembled for it) so I will have some shielding for the circuit. I also picked up a inexpensive pt2399 delay board and hope to figure out how to get a reverb sound out of it. There is a two pt2399 chip Equinox II reverb that I think sound kind of ringy, seems another guy thinks the same. He came up with a improved version of the Equinox II that made me have hope I can figure one out using this board. I wish he would have done a 3/4 volume example rather than jumping to full volume on the video. I want to have volume, gain, bass treble and reverb for controls. A jack on the back so I can use it as a head to plug into a full size speaker.


ZN7RuBq.jpg
 




New Posts

Top