Yamaha M7CL Output Hiss

[mikehallberg]

Hello all,

I am having a bit of trouble with my M7Cl v3 console. I just noticed today that when I put up any more than 6 or 7 channels at unity, no matter what the HA/Gain is set at, I get an audible hiss through the outputs those channels are routed to. I've tried switching out cables and isolating the issue, and I have concluded that it is definitely some issue with the console. I routed the console directly into a recording interface, and I got the same audible hiss. Does anyone have experience with this issue, or is there anyone that might have some insight as to what might be going wrong? Any assistance anyone can provide is greatly appreciated.

Mike

 

[Footer]

Are you on the internal word clock? On board preamp? Do you hear it when you solo on the output busses?

 

[mikehallberg]

Are you on the internal word clock? On board preamp? Do you hear it when you solo on the output busses?

Internal world-clock, onboard preamp and I'm not quite sure what you mean by solo on the output busses. Could you clarify?

 

[mikehallberg]

Also, I should correct myself, the hissing does get louder with higher HA settings.

 

[Footer]

Forgot, its Yamaha... when you Cue an output into your headphones can you hear the hiss?

A few things to try... first both physically and soft unpatch all your inputs. See if you can still get the hiss. I assume you have checked the ground on the console, that can really mess with things. When doing this unpatch your console from everything, both inputs and outputs... you only want one ground on the console for testing.

A word clock that is off can produce a hiss. I'm leaning towards a grounding problem but if you still get it when everything is unlugged and unpatched you could be looking at a word clock. A good external one is a hundred bucks: http://www.zzounds.com/item--ARTSYN...RkXaJM2dbMkqzOYx7AJinXlZYv_0PkQH5IhoCaU7w_wcB

Do you have a backup power supply you could switch to?

 

[mikehallberg]

Forgot, its Yamaha... when you Cue an output into your headphones can you hear the hiss?

A few things to try... first both physically and soft unpatch all your inputs. See if you can still get the hiss. I assume you have checked the ground on the console, that can really mess with things. When doing this unpatch your console from everything, both inputs and outputs... you only want one ground on the console for testing.

A word clock that is off can produce a hiss. I'm leaning towards a grounding problem but if you still get it when everything is unlugged and unpatched you could be looking at a word clock. A good external one is a hundred bucks: http://www.zzounds.com/item--ARTSYN...RkXaJM2dbMkqzOYx7AJinXlZYv_0PkQH5IhoCaU7w_wcB

Do you have a backup power supply you could switch to?

Here's an interesting thing I just found. I'm getting the same hiss through my headphones, even when I have the level turned all the way down on them coming out of the board. I went ahead and unpatched everything and I still get the hiss. Could this possibly be a grounding issue then? I can try to find a different power supply for it for sure.

 

[JD]

Although hiss is more an analog problem, it is wise to remember that even digital boards contain D to A and A to D converters. Typically, in the analog world, chips can go noisy. I find it interesting that even with the gains all down, you are hearing hiss from the headphone output. If it were hum, then grounding could be a source, but hiss is less likely. If every gain is down on the board, and you are still getting a hiss output, then it is time to call Yamaha tech.

 

[MrX]

A word clock that is off can produce a hiss.

That's a first. Where did you hear that?

 

[Footer]

That's a first. Where did you hear that?

I've heard small pops and jitters due to a bad clock. Without hearing the "hiss" myself it could be electrical or it could be clock related. A bad clock can cause issues.

 

[MrX]

Clicks and pops due to 2 digital audio devices not having their clocks locked is something.
Hiss? Never.