Buzz in speakers with 4B3 and BP173

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vklyushnikov

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Buzz in speakers with 4B3 and BP173
« on: 5 Feb 2019, 03:43 pm »
Hi,

I've noticed an issue in my system - buzzing noise from speakers. The system consists of BDA3, BP173, 4B3, Torus Power RM-8 and PMC OB1 speakers, I use Bryston XLR cables and set 23db gain on power amp. 4B3 and BP173 were installed 3 months ago, they replaced 4BSST and BP25/MPS1 - which were completely silent. BP173 and 4B3 are 220V units switched by local distributor to 230-240V, BDA3 is 220-230V unit. Here is what I found after some investigation:
  • Noise comes from woofer and mid woofer - woofer is loudest, I can hear it in 10 cm near the speakers. It sounds like uniform buzz.
  • Noise doesn’t depend on preamp volume level and I hear it with volume knob in zero position and without any source attached to dac.
  • Noise is loudest in right channel with all units switched on, dac can be left on standby. Removing power from dac makes noise quieter and moves it to left channel, muting preamp makes noise much quiet, and disconnecting all inputs from power amp makes speakers silent.
  • When dac is switched on swapping cables between DAC and preamp from left to right moves noise to left.
  • Increasing gain on power amp makes noise louder.
  • Noise is same with system switched either to Torus RM8 or wall outlet. Outlet is grounded and checked by electrician, input voltage is always 230V, switching system to other outlets makes same noise.
  • Noise doesn’t depend on used cables - same with RCA, other XLR cables, other speaker cables, and any power cables.
  • Noise doesn’t depend on placement of components.
  • Switching off Wifi, moving away phones and switching off all other electric equipment at home makes no difference.
  • BP25/MPS1 and 4BSST are completely silent with BDA3. I tried to identify faulty unit with switching BP25 to 4B3 and BP173 to 4BSST - without DAC at all. However every such combination has some noise. Only using BP25 and 4BSST together has no noise at all.

I tried to email Mike Pickett with this, but got no reply. Please help me to understand how defeat this noise - I don't think I should ignore it

sfraser

Re: Buzz in speakers with 4B3 and BP173
« Reply #1 on: 6 Feb 2019, 04:42 pm »
If you are not already, try using a optical cable between your source and the DAC. That may be enough to electrically isolate the signal.

vklyushnikov

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Re: Buzz in speakers with 4B3 and BP173
« Reply #2 on: 6 Feb 2019, 04:44 pm »
Unfortunately I have buzz without any source switched on

sfraser

Re: Buzz in speakers with 4B3 and BP173
« Reply #3 on: 6 Feb 2019, 04:45 pm »
If it is not to difficult, I would try it anyways.

vklyushnikov

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Re: Buzz in speakers with 4B3 and BP173
« Reply #4 on: 6 Feb 2019, 04:58 pm »
My source is USB based - it's Sonore Signature Rendu streamer. But now it is switched off and removed from setup - so there is nothing to isolate :) For me this buzz sounds like ground loop, but I don't get how this can occur with Torus or single wall outlet. I never had this issue before installing 4B3 and BP173, so I hope James will notice this topic and provide an answer from engineering team.

sfraser

Re: Buzz in speakers with 4B3 and BP173
« Reply #5 on: 6 Feb 2019, 05:07 pm »
Ah ok, I was leaning towards a ground loop too. The next logical step would be turning off and disconnecting the DAC from the preamp.  Lets see what James or Mike has to say.

Silverbullet

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Re: Buzz in speakers with 4B3 and BP173
« Reply #6 on: 6 Feb 2019, 09:39 pm »
I had a hum on my 4BSST connected to a BP26, with no sources it was still there.  I put Audioquest noise blockers on the inputs (just blank caps) and in my case it went away. Now they’re just on my unused inputs but not on the unused XLR. Don’t know if it would help you.

vklyushnikov

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Re: Buzz in speakers with 4B3 and BP173
« Reply #7 on: 7 Feb 2019, 08:23 am »
Your case looks very similar to mine, I should definitely try your solution. If caps helped that was RF interference...

vklyushnikov

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Re: Buzz in speakers with 4B3 and BP173
« Reply #8 on: 7 Feb 2019, 06:39 pm »
...And they not helped to me. Still hope for any reply from Bryston

gdayton

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Re: Buzz in speakers with 4B3 and BP173
« Reply #9 on: 7 Feb 2019, 07:03 pm »
BP-17 Cubed preamps have a touch higher noise than BP-26s but definitely have less distortion and (IMHO) sound a little better. That said, it sounds like your noise level may be out of the ordinary. Get in touch with Mike Pickett at our factory for advice.

-Gary

vklyushnikov

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Re: Buzz in speakers with 4B3 and BP173
« Reply #10 on: 7 Feb 2019, 07:08 pm »
Gary, thank you very much for reply. I already emailed Mike on Monday with cc to James, but got no reply. This is not first time when my email to Bryston remains unanswered - I'm wondering if Bryston corporate mail spam filter blocks too much.

gdayton

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Re: Buzz in speakers with 4B3 and BP173
« Reply #11 on: 7 Feb 2019, 09:23 pm »
Strong possibility - It keeps our workload lighter  :lol:

PM me your direct contact info and I'll speak to Mike about it first thing tomorrow.