Bottlehead Forum

Bottlehead Kits => BeePre => Topic started by: oguinn on March 10, 2021, 08:52:17 AM

Title: Humming when unplugging an output connected to BeePre
Post by: oguinn on March 10, 2021, 08:52:17 AM
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?
Title: Re: Humming when unplugging an output connected to BeePre
Post by: Paul Joppa 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?
Title: Re: Humming when unplugging an output connected to BeePre
Post by: oguinn on March 10, 2021, 09:13:53 AM
Sure thing, Paul.

Title: Re: Humming when unplugging an output connected to BeePre
Post by: oguinn on March 10, 2021, 09:21:16 AM
Here's a shot of the RCA cables at the BeePre end if that helps
Title: Re: Humming when unplugging an output connected to BeePre
Post by: Paul Birkeland 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. 
Title: Re: Humming when unplugging an output connected to BeePre
Post by: oguinn 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.