Odd bug/annoyance (Intelligel Audio I/O--SSP--Eurorack)

Ok, I’ve spent a few hours today trying to logically figure this one out. Perhaps someone can help me brainstorm.
So my main I/O is the Intelligel Audio I/O.
I think there’s nothing wrong with the SSP, but it does occur when I do the following:
I have a patch using Plaits.
When I output from SSP to Intelligel on L output, no problem.
When I use the right Output of the Intelligel nothing.
I’m using balanced 1/4 TRS cables.
My audio interface to my monitors is a RME UCX II
I’ve tried different cables, different inputs on interface.
It does the same if I feed an oscillators to the SSP from my Eurorack with just a input/output module.

HOWEVER…(not yelling lol, just an emphasis)

If I feed a wave from Erica synth Black VCO directly to the Intelligel on that r input then it works (sound on).
And I can have a pulse on the right and a sine on the left, both work.
But here’s the kicker, if I feed a Doepfer osc wave to the right of the Intelligel, no sound (but works on the left channel).

I just don’t get it.
I get that the Erica synth maybe outputs louder??
And I get that the obvious answer might be a defective I/O module (the input part of the module works great), but if that’s the case why would it work with the Erica synth oscillator?

Would an issue with the case power cause such issue?

The fact it’s doing something similar with your doepfer OSC, makes it more likely the IO board.

difficult to say what’s wrong with the IO board…
If you suspect it’s levels, you could take the oscillator that does work, pass it thru an attenuator , and the slowly turn it down… see if at some point it justs cuts out.

Btw: I don’t know about the Intelligel but some io boards have a ‘pad’ jumper , eg -10,-20db , perhaps this does too, the right is set on the higher setting ?!

If your not sure about the balanced cables , try pulling it half out , see if it fixes it,… if it does you are mixing balanced and unbalanced which won’t work properly.
( not sure why it’s working on L channel though )

I didn’t see anything in the manual about it. I’ll have to check it out and check behind the board perhaps. Maybe email the company and see if that’s considered normal behavior.
I’ve permutated every possible factors. I did have a suspicious cable using the half out test before posting. I’m using cables I know are faultless now. So can a balanced cable become unbalanced btw?

And why am I getting left and right out front the black VCO?
But from your knowledge of SSP nothing in its output that would explain this? Being that the SSP is digital. I saw your posts about the DC AC offset, and still trying to truly understand it all. I doubt that is the issues here

no, nothing on the SSP should cause this…

DC offsets are not relevant, an output module use AC coupling to remove this, and many Eurorack modules put out DC offsets :wink: … and the SSP is not that bad in this regard.

balance vs unbalanced.
the thing is a balanced signal has the same signal twice, once normal, once inverted.
so IF you take a balance signal to a unbalanced port, that can cancel each other out …

pulling the cable half out is a good test, since this means only ONE of those two signal gets thru, and so the cancellation doesn’t happen …
that said, most audio interfaces/mixers etc these days can cope with this… and Im sure you have tried using the working cable/input on the left then right … to verify its not the cable/input side.

also doesn’t explain why its working on one sound source and not another!

I guess you tried wiggling the input/output cables around a bit, just in case its ‘lucky’ it worked in once scenario… and its not a faulty connection.
the fact you don’t have a signal on the input LED would make me suspicious of the input side…
or perhaps some kind of grounding issue in the case?

I can’t really think of anything else… no real reason one oscillators should work, and the other not.

sorry, its one of those things, Id end up poking around , and seeing what else I could find out :frowning:

I’m assuming you’re going from SSP out to intelijel IN, and then using the 1/4” TRS OUT to the RME IN right?

Ha just realized this post is old. Not sure why it showed up in my summary today. :rofl:

It’s ok, I’ll listen. I just never had the time to figure it out and ended up using a different output module… Any suggestions?