Projet G5

This is something i've been working on for a while. It's the ax84 push pull power amp at its core but i added switchable depth/presence caps and also the scale control from Merlin Blencowes preamp books.

I currently have it all cobbled together in a project chassis but will be reassembling it in a rack chassis this weekend so more to follow this weekend.

Super nice,

it's a double-sided PCB then?
Can we see the other side?

Dr. Nonosse a écrit : ↑14 avr. 2022, 18:39 Super nice,

it's a double-sided PCB then?
Can we see the other side?

Yes it's a double sided board. I can't do it right now as my son is asleep in the room next to where everything is but tomorrow ill grab some photos of the underside.

Also note I made it so the rectifier could easily be setup as a bridge rectifier for a friend for a transformer he has to hand along with a capacitor coupled bias supply option for him.

Take it easy,
I'm just curious because I never see the sckematics, the heater wiring.....
Hu ok capacitor filter is quite different from the G5 who use self filter, why not.

Please don't wake your son for that (I know that: I'm brand new dad...)

see you.

Dr. Nonosse a écrit : ↑15 avr. 2022, 22:16 Take it easy,
I'm just curious because I never see the sckematics, the heater wiring.....
Hu ok capacitor filter is quite different from the G5 who use self filter, why not.

Please don't wake your son for that (I know that: I'm brand new dad...)

see you.

For the most part it's very similar to this with a few changes around the NFB and also has a parallel input stage.

https://ax84.com/archive/ax84.com/stati ... ematic.pdf

The heater wiring will be done manually on the sockets which are off board.

The heaters are elevated to around 70vdc and will be run as parallel pairs of bus wire from socket to socket with the winding from the transformer being twisted up to the first valve.

Hi,

Seems neat for the PCB

The heaters are elevated to around 70vdc and will be run as parallel pairs of bus wire from socket to socket with the winding from the transformer being twisted up to the first valve.

Should be 7 VDC Nope?

No I think 70VDC and the heater stay in AC.

Very nice PCB !

Dr. Nonosse a écrit : ↑17 avr. 2022, 21:17 Hi,

Seems neat for the PCB

The heaters are elevated to around 70vdc and will be run as parallel pairs of bus wire from socket to socket with the winding from the transformer being twisted up to the first valve.

Should be 7 VDC Nope?

Nah 70. The heaters stay AC but ride on top of the DC elevation reference.
http://www.valvewizard.co.uk/heater.html more info here.

Arf, Ok my mistake,
I learn something new. Thanks for that.
Good trick for reducing hum.