Clearcom/Audio feed hummmmm

[Anonymous067]

I am using a clearcom belt pack to connect the headphone output to an input on the board via custom cable.

I have a fmale 4 pin xlr, wired pin 3 -, pin 4 +, and wired to a male xlr 3 pin, with pins 1+3 jumpered, and the - side into pin 3 (I probably should have run it to pin 1 like I do with other bal>unbal), and + into pin 2.

When connected to the board, I can hear the audio great, with a nice hum. Ideas?
Solutions?

 

[coldnorth57]

http://www.clearcom.com/support/manual_pdfs/manuals_party_line/Clear-Com_RS-500_Series_Manual.pdf

Check this out i think you want pin 1 and 2 (4 pin XLR) these to go to your pin 2 and 3 on the 3 pin XLR BUT this is a line level coming off the clear com and should be going in to the baord as a line in not as a mic

 

[coldnorth57]

opps sorry yes it should be pins 3 and 4 on the 4 pin XLR going to the to pins 2 and 3 on the 3 pin XLR still line level

 

[TimmyP1955]

I think you both have it wrong:

Headset Output Pin 4 (headset audio +) to Console Pin 2 (input +)

Headset Output Pin 3 (headset audio -) to Console Pin 3 (input -)

Headset Output Pin 1 (shield) to Console Pin 1 (shield) or open (which ever gives the least noise).

Headset Output Pin 2 (headset mic Input +) open

 

[Spiceboy]

I agree with Timmy

"Headset Output Pin 4 (headset audio +) to Console Pin 2 (input +)

Headset Output Pin 3 (headset audio -) to Console Pin 3 (input -)'

You shouldnt need pins 1 and 2 on the 4 pin as they are for the Mic

If it doesnt work that way then check that the Clearcom is clean by plugging a headset in to the beltpack and making sure that you dont have hum.

Failing that try transformer isolation between the beltpack and the board.

 

[cprted]

Why not just use the program input on the mainstation? Saves all the jury rigging and frees up a belt pack ...

 

[derekleffew]

Why not just use the program input on the mainstation? Saves all the jury rigging and frees up a belt pack ...

I think that's the opposite of what Blah067 wants to do, cprted. The Master station's Program Input is used to inject a signal into the headsets. Blah067 wants to take a signal out.

See also http://www.controlbooth.com/forums/sound/8482-recording-comms-session.html.

 

[cprted]

I think that's the opposite of what Blah067 wants to do, cprted. The Master station's Program Input is used to inject a signal into the headsets. Blah067 wants to take a signal out.

See also http://www.controlbooth.com/forums/sound/8482-recording-comms-session.html.

Ummm, indeed. That's what I get for skimming.

 

[Anonymous067]

Ok. I actually just opened up the sucker to recheck.

I have a short piece of Belden 8412 going between a 4 pin fmale xlr and a 3 pin male xlr.

8412 has 2 conductors, white and black, as well as the shield.

As per Clearcom's data sheet, I wired the four pin xlr as follows.
Pin 1+2, nothing (for mic only)
Pin 3...- (low), shield (perhaps I should've used the black wire)
Pin 4...+ (high), white wire

As per standard xlr wiring for mics and line level runs...
Pin 1...jumpered to pin 3, with shield soldered to pin 1,
Pin 2...white wire...high from clearcom 4 pin.

Why the hum?

Should I have used both conductors instead of the shield? (I don't see it would make a difference though, its just an unbalanced cable...)

I didn't get a chance to try putting a DI box on the end of it, then running that into the board, perhaps that would get rid of the hum?

 

[museav]

Try Pin 3 (Phone -) on the beltpack to Pin 3 at the console, Pin 4 (Phone +) on the beltpack to Pin 2 at the console and the shield to Pin 1 at the console, do not jump Pins 1 and 3 at the console. In effect, see Schematics 13 and 17 in this, Sound System Interconnection.

 

[Anonymous067]

Try Pin 3 (Phone -) on the beltpack to Pin 3 at the console, Pin 4 (Phone +) on the beltpack to Pin 2 at the console and the shield to Pin 1 at the console, do not jump Pins 1 and 3 at the console. In effect, see Schematics 13 and 17 in this, Sound System Interconnection.

So no connection with the shield at the beltpack?

 

[Chris15]

Sounding very much like a ground loop. I agree with Brad on this one, float the audio to the console by connecting nothing to pin 1 on the 3MXLR.

Failing that a 1:1 iso transformer or tap the party line directly (same troubleshooting if noisy) or use a proper 2 wire 4 wire conversion box...

 

[Spiceboy]

"Headset Output Pin 4 (headset audio +) to Console Pin 2 (input +)

Headset Output Pin 3 (headset audio -) to Console Pin 3 (input -)'

Dont link to Pin 1 at the console end.

I know several guys who use the wiring above and it works fine for them.

Failing that (or any other working solutions) put a 1:1, 600 ohm audio transformer in line.