[Tweakman]

Hi, my first post here.

I run BCD 3, BP17 cubed, 2.5BSST2 into ATC speakers. I can hear slight buzzing noise in the tweeters and some hum in the woofer. Hum appears to be louder in right speaker.

My bp17 cubed comes with the DAC module. Using XLR cables throughout.

If I disconnect the XLR from the preamp to the power amp, the speakers are dead quiet.

I don't hear any buzz or hum if preamp is in standby mode but once it comes out of standby I can hear the buzz and hum. It's the same whether or not I have any source connected to the preamp.

I changed to a shielded RCA cable and that removed the buzz but the hum remained.

All the equipment are powered from the same wall outlet.

I noticed a flat cable under the power transformer in the preamp that goes from the front panel to the PCB behind. I have seen pictures posted on the net of the bp17 cubed with the power transformer on the left though. Not sure if there hum is due to interference from the power transformer.

Has anyone encountered this? Please let me know if and how you managed to resolve the noise issue.

[GrooveControl]

Is the BP17 sitting directly on the amp?  if so, try separating them with about 6" between them.   

[Mag]

  My experience using the BCD-3 is that you have to bypass the DAC on your BP17 cubed, if the hum occurs when using the BCD-3.

[Tweakman]

GrooveControl, my preamp and power amp are on a 2 tier rack with the power amp on the bottom shelf spaced at least 8 inches apart.

Mag, how do I bypass the DAC?

[Mag]

You should have 2 channel bypass somewhere mine is on the remote for my SP2

[Tweakman]

There's a select button on the preamp that allows me to toggle between analog and digital inputs. I choose analog and balanced 1 input and the green LED above it lights up. Do you mean that it is not enough that I didn't select any digital input and I somehow have to bypass or deactivate the DAC too?

[Mag]

There's a select button on the preamp that allows me to toggle between analog and digital inputs. I choose analog and balanced 1 input and the green LED above it lights up. Do you mean that it is not enough that I didn't select any digital input and I somehow have to bypass or deactivate the DAC too?

Yes, use the analog and not the digital. The digital I believe uses the dac. You shouldn't hear the distortion now if indeed the BCD-3 going through the dac was the problem.
  I generally piggyback a dac and a dac, you maybe able to do that with your BP17, dunno for sure. With the BCD-3 you don't need to do that and IMO will sound marginally better than piggybacking two dacs.

[Tweakman]

But there is still hum even without the BCD 3 or any source connected to the preamp's inputs.

[Silverbullet]

I have a BP26 and when I moved house experienced a continual hum no matter what I tried. Eventually I tried putting Audioquest NoiseStoppers on all my unused RCA inputs and it has been silent ever since. May not work for you but maybe they will.

[Tweakman]

Silverbullet, I forgot to mention that I have already tried RCA caps from Cardas on the unused inputs. It didn't help at all. I didn't try any RCA shorting plugs though.

[Letitroll98]

The Cardas caps, to my knowledge, aren't grounding caps and only serve to keep dust out and look pretty.  You need to ground the unused inputs, not outputs, to have any benefit.  The cheapest way is simply buy a bag of those $5 for 50 rca plugs and solder the leads together.  Alternately there are a zillion shorting plugs out there for purchase, they'll all have a positive rca plug in the cap, if they don't they're not a grounding plug.

[Tweakman]

Is it safe to try shorting plugs on the unused inputs in the bp17 cubed with dac? I didn't try them because I wasn't sure it was safe.