How much power amp affects tone

[EETStudent]

Basically, do different power amps yield different tones? For example, the power amp in the schematic I have attached is somewhat different than that of a Fender, and I was wondering if some improvements could be made for better tone, stability or noise?

[Don Moose]

The system that is the PI (where the NFB gets fed in), the power amp, OT and speaker array have a profound effect on tone. The way the springiness of the speaker's construction and the air in and around the cabinet (mechanical impedance) affect the speakers's electrical impedance WRT frequency and excursion, which affect damping and backEMF into the power amp, NFB and Presence circuits.

Giving a Marshall Plexi preamp a Fender Twin power amp and plunking that in a 5F6-A cab with 4x10" Oxfords is going to sound very different from any of the amps that went into the assemblage.

HOW all that happens, and predicting the effects of changes in that system, as far as I am concerned are black arts.

Hope this helps!

[Steve Conner]

I totally agree with Don. 101% if that's possible It's a black art, and the trial-and-error experimentation you need to do is all part of the fun.

BTW, is that schemo for one of those old Gibson amps that looks like a leather suitcase?! They're not to everyone's taste. I heard that replacing the speakers can help.

[EETStudent]

Hey Steve. lol no this amp doesnt look like a suitcase. Its actually in the form of a head and looks really good. about the size of a marshall head with black tolex and an all aluminum faceplate. Looks really good