Any builders/modders prepared to look over at my schematic?

parker_knoll

I'm looking at modding a couple of channels from my 1969 Laney PA into something  closer to a Supergroup. 

I had a crack with the following schematic. Before I get started I'd be grateful if anyone can identify any obvious mistakes. Yes I know about draining the caps before I start work. 

Thanks. 

https://drive.google.com/open?id=1rQn01bZ9lAWIDIsc24pmG_CN286NJYSU

ecc83

Can only see part of that schematic. Can you not post as .pdf?

Dave.

ICBM

It won’t be possible to any sensible degree because the whole circuit topology, especially the tone stack arrangement, is completely different. Don’t ruin a nice original amp like that to try to turn it into a half-baked version of something it can never be.

Get a Black Country Customs overdrive pedal or a Catalinbread Dirty Little Secret or Sabbra Cadabra and run it in front. 

Sorry for the lecture .

parker_knoll

The amp has six channels,  ICBM, I've already modded two of them, now im going to mod two more. Two remain stock. So it's already ruined/improved  (delete as appropriate). 

ICBM

parker_knoll said:

The amp has six channels,  ICBM, I've already modded two of them, now im going to mod two more. Two remain stock. So it's already ruined/improved  (delete as appropriate). 

OK, but you still won't be able to get even close to the Supergroup circuit without stripping two channels completely and rebuilding them as a single one with a cathode-follower tone stack and a mid control. The tone stack you've drawn above is still the 'James' one and sounds completely different.

parker_knoll

Yep, i was going for modified James as that's already in place, but if no good I'll go for a Fender-style tone circuit

ICBM

It’s not no good, it just doesn’t sound even remotely similar. Just copy the schematic for the Supergroup.

parker_knoll

I mean I'll listen to it first and see if I like it since this is relatively little work.