I'm looking for a design for a 20 Watt RMS into 8 Ohms audio power amp for guitar use. I want solid state -- MOSFET or Bipolar. I'll be using a waveform shaper/ limiter to simulate some of the features of a vacum tube amp, such as soft clipping; consequently, the power amp itself does not need to have nice distortion characteristics, compression, etc. as are sometimes wanted in a guitar power amp. All I want is 20 Watts clean. Other desired features are a reasonably simple design, and ruggedness. No class A please. Remember, guitar speakers only go up to about 10kHz so extremely high speed is not necessary for the amp. Distortion should be low but need not be ultra low.
Anybody know of a circuit that fits that general description?
Oh, and no exotic parts, please: I'd like to be able to get everyhing from Mouser.
Anybody know of a circuit that fits that general description?
Oh, and no exotic parts, please: I'd like to be able to get everyhing from Mouser.
For 20W into 8 Ohms, you need about +/-18V, or about a 40V total power supply, unless you bridge it and then only ~20V. That could be a chip amp or a Chinese module. I would just build a ~"Blameless" circuit using common parts. You could get away with TO-220 parts but maybe you want more reliability in case it gets connected to 4 Ohms, etc. It's a good idea to de-rate modules etc from the advertised power because they always advertise the maximum possible power. This applies to class-D modules as well. At the price of such modules ~$15, you could buy a variety and play with them to decide which one you like.
A bridged amp could make a portable ~22W into 4 Ohms from 12V auto power.
A bridged amp could make a portable ~22W into 4 Ohms from 12V auto power.
Why do you think everyone and their dog used the LM1875 or TDA2030 for their 20 W budget guitar amps? It’s like pressing the “Easy” button.
Since availability is back yes LM3886 would work.
And you could just use enough rail voltage for 20 watts.
The extra pad area could be helpful for thermal reasons compared
to a LM1875.
Otherwise very basic discrete circuits can work as well.
Guitar amp doesn't demand higher frequency or low distortion numbers.
Simple Darlington amps with boot strap 2nd gain stage. Can actually have
harmonic profile people chase for the so called tube like 2nd harmonic.
Its whatever. Even a Vellman K8060 kit would work for guitar duty.
Same thing lower rail voltage for about 20 / 30 watts.
typical 60 or 80 VA transformer
And you could just use enough rail voltage for 20 watts.
The extra pad area could be helpful for thermal reasons compared
to a LM1875.
Otherwise very basic discrete circuits can work as well.
Guitar amp doesn't demand higher frequency or low distortion numbers.
Simple Darlington amps with boot strap 2nd gain stage. Can actually have
harmonic profile people chase for the so called tube like 2nd harmonic.
Its whatever. Even a Vellman K8060 kit would work for guitar duty.
Same thing lower rail voltage for about 20 / 30 watts.
typical 60 or 80 VA transformer