idea for an amp

[scaesic]

i just stiched a couple of circuit ideas togetehr for a practice amp idea.

c4 from the first mosfet boost stage can disapear right?

anything else thats unecessary or worth looking into?

also, any reccomended voltages to run these on? im not sure if the tone section will run on 18v, but the first booster section should.

also, im thinking i could run the tda2030 on 25v, the spec sheet says its fine. i could just get a 25v supply and voltage diivide it to get 18?

[Mark Hammer]

As near as I can tell, R1, C1, and C2 after the MosFET booster are redundant.  C2 in the MosFET does what the second C2 does.  Given what appears to be an acceptable value for the second C1 (.0047uf), you can probably do just fine with a .022uf-.047uf unit inplace of the MosFET's C4 output cap.

If you feel like getting all fancy, consider some sort of midrange control range shift so that boost and cut can be applied in a different part of the spectrum.  I have no idea where the current values situate the boost/cut, but chances are that using a DPDT toggle or slide switch to drop the range down by an octave might be helpful.  Just use the switch to add .01uf caps in parallel with C9 and C10.  If you have a 3-position toggle, you can arrange for 3 different ranges by having two different sets of parallel cap plus no parallel capacitance.

If you find that the treble control does not give you enough bite or treble-taming, increase the value of C13.

[scaesic]

cheers! this is going to be my summer project so il hopefully get it underway within the month and post results.

i'd half thought about adding switched to change the input to match fender spec, but given the ouput impedence of the mosfet there's probaby little point in a**sing around with the input configuration.

adding more switches to change the fc values in the toneshaping circuit sounds like a good idea seeing as i should have plenty of holes to fill in the chasis, i have no idea where the fc values are just now either, but experimenting is half the fun, i just chose it because i always liked polytone amps, and a clean boost into a power amp looked pretty boring.