Humming when unplugging an output connected to BeePre

oguinn · 789

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Offline oguinn

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I have the BeePre sending its unbalanced output to a Mainline and its balanced output splitting its signal to a Kaiju and a Stereomour II. I have music playing through the BeePre/Kaiju/Stereomour currently, but not the Mainline and decided to move the Mainline across the room. To do so, I unplugged one of the two input cables and when I did so my speakers developed a hum until I plugged it back in.

I'd expect that if I unplugged an input but not an output. Is that typical behavior or is that symptomatic of a problem?

Jameson O'Guinn

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Main System: Schiit Bifrost MB, Rega Planar 6 with Exact cartridge, Eros 2, BeePre, Kaiju/Stereomour II, Jagers, Mainline

Desktop System: Crack with Speedball


Offline Paul Joppa

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Reply #1 on: March 10, 2021, 09:09:52 AM
Can you clarify?

* Neither Kaiju nor Stereomour  have balanced inputs, so how are you using the balanced out from the preamp?

* Did you mean you unplugged one channel between BPre and Mainline, or both channels?
(Related: does the Mainline have more than one source connected?)

* which end of the cable was unplugged?

Paul Joppa


Offline oguinn

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Reply #2 on: March 10, 2021, 09:13:53 AM
Sure thing, Paul.

  • I have adapters from balanced to RCA.
  • I unplugged one channel at the Mainline end. There is another cable connected to the other input (a 3.5mm to RCA cable) but nothing is connected to that.
  • The Mainline end was unplugged

Jameson O'Guinn

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Main System: Schiit Bifrost MB, Rega Planar 6 with Exact cartridge, Eros 2, BeePre, Kaiju/Stereomour II, Jagers, Mainline

Desktop System: Crack with Speedball


Offline oguinn

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Reply #3 on: March 10, 2021, 09:21:16 AM
Here's a shot of the RCA cables at the BeePre end if that helps

Jameson O'Guinn

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Main System: Schiit Bifrost MB, Rega Planar 6 with Exact cartridge, Eros 2, BeePre, Kaiju/Stereomour II, Jagers, Mainline

Desktop System: Crack with Speedball


Offline Paul Birkeland

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Reply #4 on: March 10, 2021, 09:46:51 AM

I'd expect that if I unplugged an input but not an output. Is that typical behavior or is that symptomatic of a problem?
The unplugged cable becomes a big antenna that can pick up noise and present that at the inputs of your amplifiers. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline oguinn

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Reply #5 on: March 10, 2021, 09:51:00 AM
Thanks, PB. It's a pretty long run of cable, too, so that tracks.

Mostly wanted to make sure I wasn't operating with some problem that would blow up into a much bigger problem later.

Jameson O'Guinn

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Main System: Schiit Bifrost MB, Rega Planar 6 with Exact cartridge, Eros 2, BeePre, Kaiju/Stereomour II, Jagers, Mainline

Desktop System: Crack with Speedball