Hi All,

I've been enjoying my buffalo dac for many years now but recently had a problem come up. One channel has a high pitched whining noise coming from it. The sound is really obvious without music playing and gets drowned out at higher listening volumes.

A bit of background about my setup:

• dual mono configuration that I've been using and generally kept on for around 4 years straight. Everything has been fine up until now when this randomly started occurring, without moving the DAC or changing anything in my system.
  
• the system consists of, two placid HDs, one placid HD BP, two buffalo 3 8 channel DACs with tridents, one legato
  
• source is the SPDIF transceiver connected to my macbook pro
  

Details & troubleshooting:

• High pitched noise (ear piercing) is present in the right channel on all outputs - XLR, RCA, and headphone
  
• Left channel is completely fine
  
• Right channel signal seems fine, there's just an added high pitch noise on top of it
  
• Swapped the left and right speakers and left and right channels on the amplifier to confirm that neither of those are the problem and the sound is in fact coming from the DAC system
  
• all 3 power supplies are outputting the correct voltage
  
• all board LEDs on the buffalos are lit as should be
  
• Checked for loose wires and even re-soldered some joints for the hell of it, nothing seemed wrong before and nothing changed afterwards
  
• Tried switching the placid HDs to the opposite buffalo boards and the noise remains on the right channel
  
• Swapped buffalo outputs to the legato and confirmed the problem wasn't coming from there
  
• From the tests I've tried so far I believe the problem lies on the right channel buffalo board
  

Does anyone have any ideas of what could be wrong or any further tests to try out? Thanks in advance for your help!

Thanks for the reply! I forgot to mention I did try swapping those two modules before but at the time it didn't fix the problem. I just tried firing things up again and now have completely different symptoms!

- high pitched noise is gone
- both channels output at around 50% of their original volume, I now have to turn the volume to 100% to get decent volume out of the same amplifier that I'd never push beyond halfway before. This is using the buffalo's volume with the potentiometer.
- there's some form of distortion that I believe is coming from both channels, perhaps because I'm amplifying such a weak signal?
- after a few hours of listening there was a point for several minutes where I heard some crackling/popping noises in the audio, but when I paused the music it seemed to stop, it definitely wasn't part of the source material. Turning the volume down (on the computer end) seemed to make this go away
- today while listening the right channel completely dropped out and the left went to heavy distortion and then randomly resumed as before

Unfortunately no I don't have a scope, just a DMM. Someone I know that lives further away has one so if there aren't any more obvious things to try I can get one to troubleshoot further.

Hi Russ, it's a Buffalo 3 - 8 channel version 1.02