New design humming - help requested

[bepone]

on first sight i see that you have listen my suggestions which is ok.. i have drawn on top in detail what you neeed to do..
but, cathode cap and resistor are NOT going to first filter cap.. they are going to the second (g2 supply)..so all cathode elements need to be shifted to the left part of the pcb..

then ground plane is ok if you understand how the currents are placed on the ground.. and clearance from Ub+ lines, you can make double from that ones.

[rootz]

I don't understand what you mean, maybe because we're both not native English speakers.

Do you mean the cathode resistor and bypass cap should go to the g2 filter cap?

Or do you mean they should go to B+ (output anodes) filter cap? That is what the new PCB does. That is what Fender did back in '57 and why I stuck to that design in that respect.

In about a week I'll know if this design is silent or not.

[bepone]

I don't understand what you mean, maybe because we're both not native English speakers.
Do you mean the cathode resistor and bypass cap should go to the g2 filter cap?

yes

Or do you mean they should go to B+ (output anodes) filter cap? That is what the new PCB does. That is what Fender did back in '57 and why I stuck to that design in that respect.

no, this is wrong..doesnt matter what Fender did 60 years ago , they were kinda pioneers at that time and this style need to remain in the past.

In about a week I'll know if this design is silent or not.

you need to separate charging currents first cap from the signal, this is main point..and keep those charging currents wires twisted how i show before - they are antennas otherwise..
there are many other factors too..

[rootz]

Thanks for explaining again. I went over the grounding sections of Morgan Jones' and Merlin's book. I also took a much closer look at the grounding schemes of the Peavey Classic 20 and 30 (as wel as some other models), the Blues junior and Vox AC15c1. They all do grounding different, but have some overlap. Like you said: Power tranny CT and first filter cap negative are joined together on the board. The AC15 has the power tubes cathode resistor/cap next to it, between the main filter cap and screens filter cap.

I somehow think Peavey does grounding in the nicest way. Splitting grounding between preamp tubes and power amp tubes. Normally keeping ground paths close to filter caps and cathode/grid leak reistors of the same stage. No big ground planes, but usage of small ones as a means of shielding. Looks like they mostly work with multiple star grounds on a PCB.

Biggest eye opener for me is that all those pcb's are only grounded at the input side of the pcb. Either through the input jack as the Peavey Classic 20 does or via a wire like the Blues junior. Do I see it right that it does make multiple star grounding simpler when just grounding at the input? Output jacks will be grounded to the chassis though, but are also not part of anything on the pcb.

Anyway, here's a new revision of the PCB. I did my best to group grounds and stages where they belong to. I moved the standby switch to the power transformer centre tap. It is more convenient to place it there. Let me hear what you think.

[bepone]

here i put carsbro pcb where you can get idea of clearance and ground traces

[bepone]

from first look pcb up, all the thin traces must be at least double size.. it is temperature in amp, bigger size grips more, C1 C2 are ok.. others i will check tommorow