Connecting Desk to Studio Amp

By Damien Tyson
Posted 9 January 2017, 3.07pm est

Hi All

I'm having a bit of trouble connecting the output of an Alice Air 2000 to our studio monitor amp.

The output from the desk to the amp is unbalanced. I've Kroned the red and black cable, then Kroned an RCA cable to it (basically just chopped the ends off one end, as the amp accepts RCA inputs).

But I'm getting a nasty buzzing...almost like the noise electric clippers that a barber would use. The feed from the desk is clean, RCA cable is brand new. I've tried re-Kroning it etc.

Is it because there are no ground cables connected at the Krone end?

Thanks in advance :-)


3 years, 4 months ago

A buzz on the monitoring (but not on desk output) is often indicative of a power supply fault with these. Check that the + and - 17v rails are correct first.

3 years, 4 months ago

Thanks Jonathan...I mean the C-ROOM monitor output is clean from the's only when I connect it to the amp that it isn't.

3 years, 4 months ago

The amp is fine too as connecting a CD player directly to it gives no buzzing whatsoever.

3 years, 4 months ago

OK - try connecting the RCA cables to your amp directly to the desk, as Krone wiring doesn't play nicely with unbalanced signals.

3 years, 4 months ago

Will do...what about the ground, does that need connecting?

3 years, 4 months ago

Looking at a manual online for the Air 2000. The C-room output is on a 25-pin D-type connector. To connect your amp to the mixer using a pre-made phono to phono cable then chop one end of the cable off. Then from the pin outs on the manual I've found, solder the left to pin 23 and the right to pin 11. Solder the grounds to pin 24.

The manual I found online was:

3 years, 4 months ago

Could be an earth loop (also known as a ground loop). What happens if, with the aid of an extension lead, you plug both things into the same power socket? Does the buzz disappear?

(It wasn't me, honest - there was still that bespoke-built blue mixing desk when I was last the engineer in your studio)

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