SB4000 Quad VCA Part V : Up and running

Hi again ! I found the issue, it was quite stupid : The ribbon cable was mounted backward. I mounted like I thought a ribbon cable should be mounted, without watching the pin 1 dots on the boards. So I unmounted it and remounted it in the correct way :

After this the unit worked much better (controls were correct and I was able to pass calibration step 3). But I still had not response from the LED Bargraph.

I unmounted it and saw it was mounted backward too. In fact, when mounting it, I looked to see if I saw a Pin 1 dot on it and was unable to find it, so I assumed it was possible to mount it either way. But I must have been tired because there is a Pin 1 dot on it :)
While I got the control board unmounted I saw that JMP7 was empty and I remembered it must be jumped in order to have normal bargraph behaviour (not dot style) so I installed a 2 pin socket and a jumper (so I can test the other mode if I want).

This done, the unit was working perfectly, and I was able to do all calibration. I had a hard time to calibrate the bargraph because it was always to the max for the Input level but then I noticed I mounted Trim Pots in its section with "R In L In R Out L Out" on them. So I was able to adjust all that to have a correct behaviour on all Bargraph modes.

I played with it on a drum buss, man, this thing is awesome. I was able to have like 14 db of reduction without too much shitty artefacts in T2 mode. Won't work on a very speed metal drums, but on standard drum playing it seems incredible. Can't wait to use it in real recordings / mixes.

After this I cleaned and finished the unit (including shrinking tubes, I wanted to do that only after I'm sure all is wired correctly) :

And finished the mounting :

I feared the top plate would be close to touch the transformer screw but it's not the case, even when pushing it a little. I wanted to buy some L brackets to screw the back face to the top and bottom plates but I don't think I will do it as it would mean unmount all the XLRs and stuff to be able to drill new holes. I'll use it this way and see if it's reallly an issue.

The Modushop case is the only thing I think I'm not fond of because of this missing solidarity between back face and top / bottom plates. The back face can be pretty loose in all directions : in front / back direction when pulling / pushing XLRs in/out and even in up / down direction as shown on this very ugly picture :

(Though for this one it's not that bad when top plate is mounted).

The only thing left is to buy 2 more pot nuts for the honeywell pots, as they don't come with any so they are quite loose. It's standard M10 * 0.75 nuts.

I'll post a recap soon with my own Quad VCA BOM with absolutely everything needed in it.