HELP with patchbay connections

V

verticalplunge

New member
Hi folks:

I recently purchased a patchbay to make life easier and I can't get my reverb unit to work properly. It sounds faint and muddy when going through the patchbay.

I have (I think) a balanced AP brand patchbay and a Roland SRV3030 reverb. The reverb didn't come with a manual. It has two sets of jacks on the back: one with xlr connectors and the other 1/4. I have denormaled the two slots where the reverb is going in and out and I am using balanced plugs connected to the 1/4 jacks (2 and 2). I have an Omni Studio to which everything is connected and the returns can (so the manual says) balanced or unbalanced.

When I connect the reverb directly to the Omni Studio sends it works fine. It sounds faint and muddy as soon as I hook it up to the patchbay and send anything through it, via sends or not.

I'm wondering if the 1/4 jacks I'm using are unbalanced and if I should be using unbalanced cables....???

I spent the whole day trying to figure this out and I'm stumped. I looked at Sam Ash's website to see if they sold xlr to 1/4 jacks and they are expensive--plus they sell a couple dif kind, the balanced being the most expensive--is this what I need?

Thanks!!!

-David Comdico
 
I partially answered my own question:

I did some research at Roland's worldwide site and discovered that both jacks are balanced, so that ruled out that.

I then experimented with a normaled channel and voila it worked. I just don't know why. To recap: denormaled (with reverb in and out on two channels) did not work. When normaled (fx send--reverb in; reverb out--fx retrun) it worked fine. And I can patch out from each to different instruments.

I'm wondering why this is so.... does de-normalling make the connection unbalanced? Did I overlook something???

Anyone, I'm another step closer.....
 
Sounds to me as if something somewhere is mixing balanced and unbalanced improperly.

If the cables are intended for balanced signals, they'll be TRS (tip-ring-sleeve) cables- there's be an additional "ring" conductive segment between the tip and sleeve, just like a stereo headphone jack. If you use a regular TS (guitar cable) type cable there, it will short ring to sleeve. Most gear with balanced outputs is designed to allow that, and handles it transparently (except for the 6dB level loss). However, some gear with inexpensive electrically-balanced outputs does not like that t all, than will distort and do rude things when ring is shorted to ground.

Of course, if your're driving a balanced input with a TRS cable, but the ring is left _floating_, you'll get some very funny behaviors there as well. That's what is probably going on here.

If the patchbay is truly a TRS bay, and the cables are TRS cables, you should be balanced all the way from board to reverb and back again. You should be able to do all your wiring for this particular project with TRS cables- you shouldn't need the XLR-TRS stuff here. According to Sound On Sound, the 3030 has balanced TRS I/O- so that's not the problem: http://www.sospubs.co.uk/sos/oct99/articles/rolandsrv.htm

I suspect that your patchbay is actually TS, and is leaving ring open on the returns to your soundcard. To try a workaround, use an unbalanced TS cable from the patchbay to your sound card's returns- that'll fix the "floating ring" problem...
 
I typed too slow, looks like. How, exactly, did you denormal the pairs? I don't know that patchbay: did you need to clip wires, pull jumper blocks, or what?

One possibility (since leaving the normals in makes it work) is that you only denormalled tip and sleeve, leaving ring normalled- that'll surely sound ugly!

Anyway, sounds like you have a good handle on it. It's the denormalling that is the problem.
 
Thanks for the reply Skippy.

I'm using TRS cables for all of my connections, except guitar, keyboards, and drum machine. The Omni Studio fx loop can handle balanced or unbalanced--so I'm guessing it's balanced. That leaves the patchbay....

I de-normaled it by removing the pc card and rotating it 180 degrees. Does that sound like it could be causing the problem?

Thanks again,

-David Comdico
 
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