Strange screeching noises, why?? DA conversion in vs out the box??

S

samion

New member
Hi, my first post here, good to be here :)

I've noticed a strange problem with my new DAW I've built. I put in the RME 9632 (going unbalanced out to an amp) and it all works fine except at moderately high volumes I hear the screeching of computer programmes i.e. when I open up Sonar or even move the mouse around this screechy high pitched noise comes out... !!

Oddly, when I go out of the 9632 via ADAT into my focusrite saffire pro 40 and go out from that to the amp it's perfectly quiet!

So:

RME 9632: unbalanced audio out --> amp --> monitor Ones SCREECHING

RME 9632 ADAT out --> Focusrite Saffire Pro 40 : unbalanced out --> amp --> monitor Ones PERFECTLY QUIET!

I'm a semi-newbie here, and it confuses me. I'm probably wrong but it seems as though when the 9632 is doing the DA conversion it picks up all the very slight micro difference in computer strain caused by moving the mouse around and this somehow interferes with/strains the DA conversion to give me screeches... but when I send that data out digitally to the Focusrite to do the DA conversion, even though it's passing through the RME card and it's going out unbalanced it doesn't.. therefore I'm guessing it's a DA conversion issue of the RME 9632.

I know the general rule is get the ADDA done out the box but you'd expect RME to be built pretty solidly surely!?

I'm using a Tacima power conditioner which I'm pretty sure helps cut down this noise but it doesn't eliminate it at all.

Am I right in what I'm thinking? Or am I doing something wrong?

Any help much appreciated!
 
Some computers are inherently noisy. The most usual fix is to go for balanced audio all the way through.

My earlier computer, with a firepod and unbalanced leads to active monitors was dead quiet.

The newer one, with the same configuration, was full of that noise. I switched to balanced leads which fixed it totally.
 
gecko zzed said:
Some computers are inherently noisy. The most usual fix is to go for balanced audio all the way through.

My earlier computer, with a firepod and unbalanced leads to active monitors was dead quiet.

The newer one, with the same configuration, was full of that noise. I switched to balanced leads which fixed it totally.
Click to expand...

cheers buddy, the only thing I don't get is why it's fine going from the RME ADAT out.

If it was simply a general computer noise problem then I'd have thought that noise would carry through the ADAT too. That's what gets me thinking this is purely a DA converter issue within the soundcard i.e. that picks up the computer noise whereas the rest of the RME circuitry doesn't and so passes a clean ADAT out signal. Therefore once the noisy DA conversion has already been done I don't see how going balanced downstream will then help? But then I'm a newbie with this stuff so may be bang wrong...
 
I had a similar problem with my Gigabyte motherboard and a Delta 44 PCI card. Something about this motherboard caused that same electronic noise when the mouse was moved, programs opened/closed, windows re-positioned, etc. I had all balanced cables, the works. I ended up going with a USB interface and the problems were alleviated. The onboard soundcard on this mobo is noisy as hell also.

Can you try a different PCI slot for your RME? Maybe one farther away from the power supply, or farther away from the graphics chip. I didn't have that luxury since my Delta was using the mobo's only old-school PCI slot.
 
Tadpui said:
I had a similar problem with my Gigabyte motherboard and a Delta 44 PCI card. Something about this motherboard caused that same electronic noise when the mouse was moved, programs opened/closed, windows re-positioned, etc. I had all balanced cables, the works. I ended up going with a USB interface and the problems were alleviated. The onboard soundcard on this mobo is noisy as hell also.

Can you try a different PCI slot for your RME? Maybe one farther away from the power supply, or farther away from the graphics chip. I didn't have that luxury since my Delta was using the mobo's only old-school PCI slot.
Click to expand...

Thanks mate that's a good suggestion. I'll check out what PCI slots I have left and do some jigging about.

If it doesn't help I think I'll just stick with ADAT or as you say go the USB route or something.

I'm quite disappointed with RME you'd have thought a top brand like that would be shielded better perhaps...
 
samion said:
I'm quite disappointed with RME you'd have thought a top brand like that would be shielded better perhaps...
Click to expand...

I think the problem is less to do with the shielding in the RME and more to do with the design of the motherboard. Anything using unbalanced leads, no matter how well designed, is going to be susceptible to interference.
 
It works from the ADAT out because the adat out is optical. The units are completely isolated from eachother electronicly
 
McMajik said:
It works from the ADAT out because the adat out is optical. The units are completely isolated from eachother electronicly
Click to expand...

+1!
Try an audio isolator traff box like Art Cleanbox ll (or better the Orchid if you are in UK ) . Or remove both shield connections from the plugs (RCAs?) at the amp end.

I have read scads of posts about "noisy" MOBOS but I have been through some 6 or 8 myself and never got one?

http://www.orchid-electronics.co.uk/dual_isolator.htm
Dave.
 
ecc83 said:
I have read scads of posts about "noisy" MOBOS but I have been through some 6 or 8 myself and never got one?
Click to expand...

Count yourself blessed!

I started recording with a digital system in about 1998, using an emagic pci card. From then up until around 2010 I had noise-free listening. That twelve years represents about three or four computers. The most recent one was the noisy one, until I replaced unbalanced with balanced to the monitors. I believe more recent motherboards are noisier than their predecessors, and may be a consequence of design and manufacture.
 
gecko zzed said:
Count yourself blessed!

I started recording with a digital system in about 1998, using an emagic pci card. From then up until around 2010 I had noise-free listening. That twelve years represents about three or four computers. The most recent one was the noisy one, until I replaced unbalanced with balanced to the monitors. I believe more recent motherboards are noisier than their predecessors, and may be a consequence of design and manufacture.
Click to expand...
I did not get my first "serious" music computer till 2006 and that worked with a Behringer BCA2000. Badly, well, great when it worked but not often. I then went for the PCI/mixer regime and have never looked back and am now on the fourth PC using 2496 cards which are of course unbalanced. I am scrupulous to the point of anal about grounding schemes and have never had hum loop or "screeching" problems.

The fact that yours were fixed by a balanced system leads me to think that the problem WAS more grounding issues than any inherent noise in the MOBOs? Else where did it go?

Dave.
 
You must log in or register to reply here.
Back
Top