Santiago Alvarez (electronics engineer, JVM, YJM, AFD...)

[santiall]

Wrong forum.

I hope they don't ban me... It won't happen again, playing is overrated, let's buy more gear!
actually, does anybody here actually play guitar?

 

[Szlast]

there are few arguments to make them different. The phase splitter needs to drive 4 tubes instead of two, the output impdance of two tubes is ~half (you approx. double the transconductance), the output transformer, most likely, has lower resistance. Then the output votlage, for the same impedance is 1.4 times so you would need to compensate with the feedback. etc. On top of that, many 50W marshall power amps run at a relatively low voltage (the voltage that was in the datasheet btw) so the tubes are not even operating in the same point.

so yeah, there are a few arguments that points to potential differences. That doesn't mean that you couldn't design a 50W that is indistinguisable from a 100W, I guess Hi-Fi guys do this (or try to) all the time, but for a guitar amp one may want those two to be different.

I mean tonally if 100W sounds "better" than 50W? I know that there are guys that hear type of tolex of the head but realistic hearable difference:) 100W now is not needed as it was in old days where there was no stage sound systems.

Also have a quiz for you all. I recently wound my first output transformer in the most simple 3 sectional way on old EI102 core from I guess not top quality steel. I recorded two samples on my DIY 50W JCM800 one with bought transformer from top quality company in Poland, transformer is 5 sectional EI96 with top quality steel and second with this my. Can you guess which is which and why?

Samples where recorded as follows: Amp -> DIY reactive load from Marshall forum -> Tonex one -> DAW -> IR "LT TV MIX 7 500N" from Leon Todd free pack. Amp settings and guitar the same.

Output transformer test – Google Drive

drive.google.com