SSL 4KG+ crosstalk bet. left and right on the stereo returns (651) (SOLVED)

[RoyMixer]

SSL 4K - Anyone seen crosstalk between left and right on the stereo returns on the 651?

I put a 1K tone to right channel and noticed it leaked into the left side and vice-versa on st returns 1-4.

anybody else seen this?

R

[radardoug2]

At what level? You need to give us some figures.

[RoyMixer]

I'll re-do the test tomorrow,  I found it while calibrating my outboard to unity while starting a mix (experienced this on two different desks.)  both G series.   most likely was -18 dbu, that's what I cal my outboard FX to.


I had 1k @ -18d  patched to Echo return (right input) and would see the  LF (Mechanical VU) meter move up slightly from its resting position.

I'll check it again.
R

[RoyMixer]

OK solved!
-was dirty ST RET. cut switches.

[jimlfixit]

Being at SSL from 1980-87 I have obviously seen a lot of changes there. The 651 is mainly wired with twisted pair looms in Kynar 24-26 solid core wires made laid out on looming jigs and tinned and finally wired into the 651.
Some of the wiring was grey twin screened cable and, if my memory from many decades ago serves me right, I think the echo cards, as well as others were wired with this (and also some single screened cable I think) which was probably bought from RS Components at the time. Bear in mind there was not the vast amount of wire and cable varieties which are available today.

[RoyMixer]

Hi Jim,

Thanks for posting here! I do enjoy hearing about your experience with SSL.    I was looking also at the echo return schematic,  The summing of left and right is passive for the SPIN control, always fascinating to look at these for me.

Best,

Roy