noise on patchbay

[dawner]

hi everyone!

this is actually not a protools question, but the problem affects my Digi001, anyway:

i recently connected my Digi001 inputs to a Behringer patchbay - what i now notice is a not very loud but annoying high-frequency noise on the inputs.

does anyone know what the reason for this might be?

i thought it might be the cables but actually these are cables for patchbays...dunno [img]images/icons/confused.gif[/img]

thanks for any suggestion

[dawner]

sorry for the accidental double post...

[bjoneill74]

Dawner

This may seem like a dumb question, but what kind of cables are you using? Are they balanced/unbalanced? What mode is the patch bay?
Normalled/Half Normalled?

[dawner]

the patchbay is switched to half-normalled

the cables from the patchbay to the Digi001 are stereo-1/4" cables

at the front i am usually connection mono-1/4" cables

[crawl2112]

dawner,

Can you post your I/O for your patchbay?

I believe the outputs of the digi 3-8 are unbalanced. You may want to use unbalanced in the back when connecting from digi.

Couple of things that I found out when wiring my patchbay.
Some inputs and outputs are not all balanced. Using balanced cables to connect to unbalanced In/Outputs caused feedback loops.
Lifting the ground or ring connection at the output of the cable solved my problem. Or using unbalanced cable for any unbalanced output

Hopefully this will help for you and I hope that i haven't confused the issue.

cheers,

[bjoneill74]

I've experienced the opposite..
I used unbalanced cables from my monitor outs to my mackie mixer or straight to the monitors and that caused some quiet, but annoying noise.

I switched back to balanced cables and all was fine. Good balanced TRS cables aren't cheap.. and it's not easy to find them in decent lengths.

[dawner]

thanks for your help.
i just experimented a bit with different cables and it seems to be that i should use unbalanced cables...how simple solutions can be [img]images/icons/smile.gif[/img]

[crawl2112]

Originally posted by bjoneill74:
I've experienced the opposite..
I used unbalanced cables from my monitor outs to my mackie mixer or straight to the monitors and that caused some quiet, but annoying noise.

I switched back to balanced cables and all was fine. Good balanced TRS cables aren't cheap.. and it's not easy to find them in decent lengths.

<font size="2" face="Verdana, Arial">bjoneill74,

I still use balanced cables from my digi out to mackie ins. I just lifted the ring connection. All seems to work fine - no noise or feedback.

As for cables. I put them together myself. It was easier and cheaper then finding the cable lengths that I needed at a decent price.

Originally posted by dawner:
thanks for your help.
i just experimented a bit with different cables and it seems to be that i should use unbalanced cables...how simple solutions can be

<font size="2" face="Verdana, Arial">dawner,
I did a lot of experimenting and I am comfortable with my setup eventhough, it may not be the perfect setup.

cheers,
Scott

[bjoneill74]

crawl2112

I have to use balanced cables for it to be clean.

I have balanced cables going from the Digi001's monitor outs to channel 19 & 20 on my mackie 24.4 board.. then I have balanced TRS to XLR cables connecting the Mackie board to my active monitors.

[crawl2112]

Originally posted by bjoneill74:
crawl2112

I have to use balanced cables for it to be clean.

I have balanced cables going from the Digi001's monitor outs to channel 19 & 20 on my mackie 24.4 board.. then I have balanced TRS to XLR cables connecting the Mackie board to my active monitors.

<font size="2" face="Verdana, Arial">bjoneill74,

Agree and correct me if I am wrong but I think the monitor outputs are balanced so, all should be fine with your setup.

I don't use the monitor outputs, just the mains so my setup differs from yours a bit. Anyway, I use 3-4 output from the digi as a monitor into my mackie if necessary and just keep the mains for main output use.

cheers