Class D guitar amp?

[Printer2]

Has anyone used a class D amp for guitar? I am curious about using something like the TA2024 for a small practice amp. I did a bit of searching and could not find any information on how it sounds and takes being overdriven.

[teemuk]

I guess you'd want the overdriving take place in the preamp.

[Nigel Goodwin]

It's a really bad idea to over drive ANY solidstate power amp - and you should certainly never do so with a Class D one.

[Andrew Eckhardt]

Class D has completely "invaded" electric bass amplification but mainly because lots of players use hundreds or a thousand watts or so and get most if not all their sound at the preamp level and through the speakers. The size and weight reduction is a big factor. Class D would make a fine guitar practice amp so long as you follow the same plan in getting the sound, athough the interplay between tube output stages and speakers is usually given a lot more consideration for guitar.

[Printer2]

I understand the advantage of class D for bass, you need a lot of clean power to make a lot of sound. But with guitar the amp overloading is a part of the sound generation. And no, it is not any worse if a solid state amp gets overdriven as long as you are happy with the sound.

I have made a few guitar amplifiers running class AB in the past but have no experience with Class D when they hit their maximum output capabilities.

My preamp section will have it's own distortion signature but let's face it, at some point in time the output stage will be driven beyond maximum. Just the nature of guitarists. The question is what does it do to the sound?

[Andrew Eckhardt]

The overdrive performance of class D amps is pretty much Bad, meaning basically there is nothing to be desired there. Without having actually tried it a lot I'd say the conventional triangular wave carrier / comparator type modulation schemes will give the mildest clipping, but I doubt it's going to be a sound you want. With the cartloads of signal level overdrive circuits being done for guitar I seriously doubt you could beat the sound with a clipping class D amp. It probably wont kill your amp, but it will probably make you want to turn it down.

[theAnonymous1]

From my experience with small class-d amps; when they are driven into hard clipping they produce a sharp clicking sound on top of the heavily distorted audio signal.

Not the least bit desirable.

[Andrew Eckhardt]

That sounds like something especially a self oscillating circuit would do. IIRC Marshall once did a push-pull transistor guitar amp with an output transformer. I suppose you could add a transformer in the output of a class D output stage, even split it apart into two push pull section with N devices, with the feedback coming off the transformer. Maybe you could fiddle with the shape of the carrier to try simulating the compression of hard driven tubes. It could get pretty fancy. By the time you were done you'd probably have most if not all of a tube amp, at whatever output capacity.

[wakibaki]

You can build a practise amp with a class D amplifier. Why not a TA2024? Only thing is, it's stereo.

If I was going to do this, I'd run it into a regular efficient guitar speaker in an open back cab A small Celestion or Jensen. Two in the case of a stereo amp. I'd buy a Sansamp or other DSP amplifier emulator/effects pedal (Behringer V-amp?) and use it as a front end. I'd fiddle with the main volume control between the Sansamp and the class D so that you couldn't overdrive it.

That's probably not quite what you had in mind, but it would probably give you the most satisfactory outcome.

w

[Printer2]

I was just cruising EBay for a small amp to throw in a box as a practice amp. A guy I work with is retiring and I was going to throw something together for him since he liked an amp I built years ago.

Not really planing to do much development, have a few ideas on the preamp, people have done a lot of work since I played around with the stuff. I just thought if I could shed a few pounds of transformer weight he might appreciate it. Just looking for 10w to put into a 8 ohm speaker.

Did some reading on the TA2024 and got the impression it would start to distort but continue putting out power. Some of what I read makes me think it might be the protection circuitry that causes some of the funny sounds. I think I may pass on giving it a try for mow.

So now I was thinking of a TDA2030 or possibly a TDA2005 in bridged configuration. Then I can spend my time playing with the preamp section.