BHK Pre Sound Bleeding Between Inputs

I just hooked up my BHK pre and I noticed something weird, which I wanted to see if this is normal. I connected my AVM 60 preprocessor to input 1 (singled ended) on the BHK. Input 1 is set to home theater bypass and the HT bypass volume is set to 100. Input 2 (balanced) is connected to my DSD. If I keep my music playing on the DSD then switch inputs to Input 1 I can slightly still hear the music playing even though I have selected a different output. Not only can I slightly hear the music I can also hear noise. The best I can describe this noise is a higher pitch hum. It’s not extremely loud but it is noticeable from my listening position 12 feet away.

If I lower the HT bypass volume to about 70 it’s a lot less noticeable but my assumption is that I should never hear anything from something connected to a different input.

Is this normal? Have any of you ever ran into this situation with a BHK pre?

I just tested this on my setup, BHK/DSD/prepro. HT bypass is set to 75 on my system and when I leave music playing on my DSD (I’m burning it in) and switch to the prepro input (5) its dead silent even with my ear next to the speaker. DSD input is 1 and it’s volume is 85 with attenuator on.

Ps. I am all balanced connections tho.

Thanks for checking! My DSD volume is fixed at 100 at the attenuator is off, since I planned to control the volume using the BHK pre. In any case I don’t think this should matter since when I switch to a different input I shouldn’t hear anything from the other input. Hopefully the PS audio guys can chime in when they get back to the office on Monday.

@goblue - did you get this resolved? I’ve discovered that my BHK pre does the same thing. DSD @100 and I can hear it in th background on other inputs. I only hear it now as after Windom I upped the DSD volume to 100 and turned off the attenuator.

Sorry for the late response, I haven’t been on the forums for a while. I did talk to PS Audio support about this a couple time. The answer I got from them is that this is how the product is designed. Personally I think that is kinda crazy for such an expensive piece of equipment and also since I own a lot of other good gear that doesn’t exhibit this issue.

To answer your question, over time it just went away. I have no answer to why the sound stopped bleeding but it just magically went from being very noticeable to not happening at all. I used to literally be able to play music on the DS and without hitting pause I should switch to the HT bypass input and I would still hear music but at a very low volume.

Thanks @goblue - I agree it’s crazy that equipment at this price point should have such an issue - mine behaves just like yours did when I have it on HT bypass.

Hopefully, like yours, it’ll go away over time.

Don’t have the equipment, but was single ended inputs a common factor?
Could be more an earthing/common related issue rather than an actual fault in the design - i.e. the input design used is more sensitive to earth return issues on single ended because it has proper balanced inputs and design throughout.

Just a thought - it’s really not easy (or sometimes, possible) to account for every external configuration, impedance, and earth return condition in a design, at least not without making compromises in other areas.

That’s a pretty interesting theory @joma0711 - my pre-pro connection into the BHK is indeed RCA, while everything else is XLR.

1 Like