Soundcraft 600 Discrete summing board

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Active member
Jul 6, 2012
Hi !
I have a Soundcraft 600 that i customized a lot in the past ( For Dub reggae use ) , but after 10 years of mods / test etc... the master channel is really dead . I spend 1 week to find a solution but i start to get an idea yesterday and want your opinions / advice
I have a Yamaha PM430 in the studio too and was always surprised by the sound . Ok it's not a Neve or API but there is something cool for the ears .
So i decide to take a look on the shematic ( attached ) , especially on the master channel / Summing parts because the use of discrete opamp and transformer at XLR output

My idea is to remove the master out from the Yamaha PM ( ALL circuits yes :) and install the circuits on my Soundcraft !

I have space for it and already all connection avalaible in rear of the console ( I want to use only 12 channel ( instead of 24 ) ) I will not use this console for recording, only edit and Dub with stems .

The only "problem" maybe is the voltage . The Soundcraft Console use +17 / -17 . The Yamaha use +22 /-22 for dicrete opamp and +15/-15 for the rest
I need to build a new power supply for it ? Or I can try with my PSU .

What your opinion about that ?

I'm interested in all opinions

My Soundcraft console look like this :

I attached the PM430 shematics with annotation
and a Soundcraft Channel module with annotation also

Thanks in advance
Sorry for bad english sometime :) I m french ...


  • Soundcraft Channel.pdf
    225 KB · Views: 19
  • Yamaha-PM-430-MOD.pdf
    835.4 KB · Views: 14
Last edited:


Well-known member
Staff member
GDIY Supporter
Nov 30, 2006
Hickory, MS
how many of the master section functions are dead? Modern op amps are much lower noise and higher performance than were available back when that old soldier was designed. It might be worthwhile to upgrade the bus sum amp with modern silicon.


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