Ist it just me . .

[gearhead]

For all Trainwreck schematics, shouldn't the B+1 tap be to the left of the standby switch, and not to the right?

[RJ Guitars]

well.... it can be on that other side and be entirely functional. However, at least for the Rocket amp, this allows a little less of a surge against the rectifier tube, which is a good thing. Those big caps really slam the rectifier tube if you line them up and hit them all at once.

It's not entirely clear to me why KF would have chosen that for the solid state rectifier amps.... maybe someone knows that answer?

rj

[Wayne]

I don't know why Ken did what he did, but I do know that SS rectifiers don't like big surges either.

W

[rooster]

OK, I am not understanding what is being said I guess.

Isn't the switch SPST? Are you asking why the positions of the 2+1 wires aren't reversed? Yes? KF's switch was vertical on the Kelly, there was no left or right in this case, maybe this is why. Eh, but even so, what does it matter?

As to current surge, the 'surge' would be to the 80uf cap(s) at power on, not to the 40uf + 20uf(X3) that follow it. And here KF stops the inrush of current with the Standby switch, which is a standard design for Marshall and Fender.

So the Rocket is the same thing. While its true some would suggest that 80uf is too large an impedance load for a GZ34, the tube is slow to ramp up which makes it a good rectifier for this application - if you use the Standby switch. When the Standby switch is thrown, with 80uf in place it is actually easier on the tube to deliver the needed current to the rest of the circuit than if it was 20uf or 40uf. This is an OK design in my book, even though the impedance is a bit high. I mean, its working, right?

An AC30 has a 16uf cap in the same position and the bass freqs on it are pretty horrible. But it has no Standby switch, which means if you replaced the 16uf cap with 80uf - to help the bass - the rectifier is going to be working way too hard. No, KF did well with both these amps, IMO.

If he had skipped the Standby switch on the Rocket, well, then I would saying something different here.