Milestone 1 passed and beyond!

Recapping preamps, done!
Balanced inputs on channel 7 and 8, done!
Recapping PSU done!

This wasn't as much work as I anticipated. I definitely thought that the piggy board mod would be more hassle. But sometimes you are just lucky I guess. Karma I hope. There is two variants on the 7 and 8 channels and hopefully I will get to test it out this weekend.

When I ordered PSU caps I couldn't resist order OPA2134 and OP275 for one channel so now is channel 1 modded as Ampex 354 explained in the gearsutz thread, with new amps and coupling caps removed. I didn't do the EQ mod or gain reduction mod. I don't remember if he did so, but I added 100nF decoupling on the pins for the new amps and upped the supply rail bulk caps C16, C17 from 10uF to 47uF. I also added an extra ground cable from the far end of the board back to the ground connector hoping to reduce ground path resistance.
I cannot say anything about sound quality improvement yet but the noise floor on channel 1 was significantly reduced by this mod.

Decoupling caps on the solder side.


Little dark picture but this is the board with the extra ground cable. I really want to try stargrounding one board and break the busground, adding a cable from the preamp board straight to the PSU ground and see what impact that would do on the noise level.