Group Outputs cutting in/out

[zane]

hello all

I've been running into a problem a bunch and wanted to see if anyone here had any insight.
So, its pretty standard for me to use the small fader to send to a Grp Out that is patched to a compressor or an effect and brought back on another channel (reverb, delays, parallel compression etc...)
Quite often I notice that 5-10 mins after I set a level that I like, one side will be missing. (lets say I'm using Grp Out 9-10 to send to a pair of distressors, the left distressor (gp 9) will be gone.) so i have to work the small fader and work the line trim to 'bring it back to life'.
this would be fine if it was just every once and a while, but its pretty non stop.
whats even stranger is that my assistant and I noticed that its almost always the left side of the group outs (ie-its we're using grp out 13-14; 13 will be weird. if we're using grp out 7-8; 7 will disappear) no matter what channel, and no matter what group output, it seems like we just can't get away from it.

now, it could be a coincidence, but it seems like an awfully strange one.

One other thing, it doesn't seem to be the group out assign switch btw, its def that thing of it just needs enough voltage and then it kind of snaps back to life.

anyone here have any expierence with such an issue or insight?
I was of the belief that that part of the routing of the desk was pretty passive and not much to it. bad caps? always on the 'left' side? 

[sintech]

The send side of things is very simple..

The small fader feeds a buffered output, and if you hit the pan button, it adds another two IC’s into the chain. (one for left and one for right, also attenuating the signal for the pan law)

I think this is down to dirty routing switches acting as ‘Dry Joints’ you’re having to push the signal through to get a good contact.

How does the routing sound, when moving the routing buttons up and down?

And next time it happens, exercise the routing switches and see if that fixes without having to touch the small fader.

Can't think of anything off hand that would effect one channel and not the other.

[radardoug]

It definitely sounds like a switch problem, and there are several switches besides the routing switches that could be causing the problem.
Don't forget EQ and dynamics switches in the parts that can be routed to the small fader, as well as the pan switch . Try to operate the switches in order next time you have this problem, and pin it down to the right switch. Also note that troublesome switches will show up anytime by putting tone through them and exercising the switch, if it sounds crackly its on its way out. Often you can exercise the switch a whole lot as this wipes the switch and helps clean it.

[zane]

hm, ok thanks.

I usually check the split switch, eq in/out switch, group pan, route, direct as well..
I can try to be more diligent about working the group assign switch itself, but thus far, the only thing that seems to give definative results, is cranking the line trim all the way for a second, or turning the small fader all the way up for a second (this doesn't seem as succsesful as the line trim)

I'm get switch crazy tomorrow and report back

[zane]

well, after another couple days of mixing, I can report back that it almost def does NOT seem to be related to the group assign switches themselves. the only thing that seems to play a role is exercising the small fader all the way to the top, and/or exercising the line trim pot all the way to the right.

i guess it could be pure coincidence, but thus far i've only seen this behavior from the odd numbers, for example: 9, if its 9/10, or 13, if its 13/14. it's never been the even numbers.
weird right?

[sintech]

As these are mono channels, nothing control voltage wise from the centre section rules just the odd numbers over the even.

[zane]

So Andy, you'd still go with your instinct that it's just dirty switches (probably routing assignments) and any 'pattern' is most likely just a coincidence, yeah?

[Druhms]

The Stereo Grp you are making and then sending out to wherever,  is it a signal that is panned hard left and hard right?  If so,  just select the grp 7 for left and then grp 8 for right.  Don't engage the pan function.  Even if it's not hard left and right, disengage the pan button and see if there is any change.
Good Luck!
JJ

[Druhms]

P.S.  Or, just try reversing your pan settings.  On the Channel as well as the Groups.  Does the problem stay on the left or is it now on the right?

JJ

[sintech]

Yeah JJ's right, if you think, with the pan button out at the top, it's an identical signal being sent to the whole matrix, so it would be cool to reverse this from even to odd.. and see what happens.

[Clip6]

Maybe someone will chime in that's done facetime diagnostics but some of the SSL techs do this. Ross Alexander does this I think. Dave Thibodaux does.

You have an iPad? Gearslutz has a list of techs in the SSL techs thread.

[radardoug]

Your symptoms are definitely indicating a change to a high resistance condition in the signal path, normally switches. But don't forget the other possibilities. Are you patching this signal and monitoring after the patching? Could be dirty jacks/cords.
Pots and faders also fail in this way.
Then there is the possibility of flaky card contacts on the various cards plugged in to the channel motherboard.
Aren't intermittents fun????http://forum.sslmixed.com/Smileys/default/undecided.gif

[zane]

some good info here.

here's an exact example of the workflow:

snare drum coming up on channel 9.
ch 9 small fader set to 'output' and sending to grp out 13-14 (not using the pan in the grp assign)
grp 13-14 patched into a pair of distressors
output of distressors return to two other channels.

i will set the send level via the small fader and everything will be sounding great. 10 mins later, i'll realize the snare is way quiet on one side and when i go to solo it, notice that its not sending to the first distressor any more. working the output swith, 'kind of' does something...working the grp 13 assign swith does NOT. but what does bring it back, is jacking up the small fader all the way, or more commonly, turning the line trim of ch 9 (the snare) up all the way. you can hear it just snap back to life and its back. that is again, until 15 mins later when its gone again.
VERY not cool when trying to mix. constantly having to check everything is still getting sent around.

so yeah, thats where i'm at.
the desk def sat unused for a year and was not properly stored, but at this point, its been up and running for a a few months, was completely clean module by module and all buttons were exercised. thats not to say they can't be exercised more, just trying to figure out if its

a)just an old crusty switch on an old desk that needs to be worked
b)there is something else at play here. like a capacitor, or the like...

[sintech]

Zane when it happens again.. forget the good side of the said chain, but look at the channel that's not working.

Work backwards...solo the bad channel, and put the routing switch in for the other Distressor, if it feeds ok, you know it's a bad routing. If not work back to the small fader output switch, and so on.

[radardoug]

Try using tone, its much easier to work with. Start with the tone at fairly low level, otherwise it will probably break over and the fault will be fixed. When you put tone on and move the small fader, does it sound clean? If not, your problem is dodgy fader.