[HooStat]

I have my 4BSST2 hooked up to a preamp with a home theater pass through.  When I do not have my preamp hooked up through the HT pass through, but I select this input, I get a loud buzzing.  When I switch away from the input, I get a pop in my speakers.  All other inputs are dead silent.  I was told that some amplifiers don't like having open inputs, which is essentially what happens when the HT pass through is selected without a component hooked up. 

Just wondering if this makes sense. 

[SoundGame]

I have my 4BSST2 hooked up to a preamp with a home theater pass through.  When I do not have my preamp hooked up through the HT pass through, but I select this input, I get a loud buzzing.  When I switch away from the input, I get a pop in my speakers.  All other inputs are dead silent.  I was told that some amplifiers don't like having open inputs, which is essentially what happens when the HT pass through is selected without a component hooked up. 

Just wondering if this makes sense.

I'm confused with this question.  If you don't have your preamp HT passthrough hooked up then why are you selecting that input?  Kind of like the question to the doctor...it hurts when I pinch myself...the doctor's answer is don't pinch yourself.
If you're just wondering how your preamp is handling the HT passthrough switching then wouldn't this question be better directed to the manufacturer of your preamp... :just a suggestion.

[brucek]

I have my 4BSST2 hooked up to a preamp with a home theater pass through.  When I do not have my preamp hooked up through the HT pass through, but I select this input, I get a loud buzzing.  When I switch away from the input, I get a pop in my speakers.  All other inputs are dead silent.  I was told that some amplifiers don't like having open inputs, which is essentially what happens when the HT pass through is selected without a component hooked up. 

Just wondering if this makes sense.

A common complaint of HT passthrough setups are ground loops. They can be quite tricky to eliminate. This sounds like a classic ground loop.

At the very least, be sure all components are plugged into the same leg of your power panel.

Remove all inputs to the HT processor to see if it's a source component feeding the processor or the processor itself that is the ground loop culprit - then add the components back individually to see when it buzzes.

brucek

[HooStat]

It looks like it is an issue with the Bryston.  I have a passive preamp, a CD player, and the bryston hooked up, all plugged into the same dedicated 20 amp circuit (no power conditioner).  That is it.  Everything else is unplugged from the wall.  I have a receiver that I am using as a preamp processor hooked to the HT pass through, but it is unplugged.  All video connections are unconnected.  The TV us unplugged.  The preamp is completely passive.  I have been working with the preamp manufacturer, and this seems like the only possibility since the preamp has no active circuitry.

[Phil A]

My old 14BSST did not care for the HT Bypass either.  Not quite what the OP experienced though.

[BrysTony]

I happen to not have anything hooked up to my HT bypass but it had not occurred to me to switch to it since there is nothing attached.  However, because of this post I switched it in to check it out.  My 7BSST²s are dead quiet.  FWIW...

Tony

[HooStat]

It looks like there is just a little bit of DC getting in there somewhere.  It is not the passive preamp.  In HT passthrough, it is literally a direct-wire connection from input to output.  The company (Placette Audio) has done shows with Bryston and loves them, and he doubts it is the Bryston.  But we are struggling to figure out where this little bit of DC is coming from.  So, I think the Bryston is fine too.  In fact, I tried my second Bryston (9BST) and the same thing happened.  I wonder if there is a little DC getting in there from outside the house.

I have to say, also, that the Placette is an amazing product, the Guy Hamel, whose company this is, has been extremely helpful in working through this.  If all else fails, we will just put a resistor across the pass through to drain any DC.

[HooStat]

Is it possible that the amp is "leaking" a little DC?  It wouldn't take much since the pass through is basically "full volume".  So even a few microvolts might be audible.

[BrysTony]

You stated that you have an unplugged receiver hooked up to the HT receiver.  Does it have an antenna or cable connection.  If so it could be the source of ground loop noise.

Tony

[HooStat]

There is no longer a ground loop.  The issue is popping when switching inputs.  Specifically the "pass through".  The ground loop was one possibility, but that has been eliminated.  Everything is plugged into a single dedicted 20A outlet, and it is just the amp, a CD player, and a preamp.  Everything else has been unplugged and disconnected (including disconnecting the cable from the unpowered cable box).  There is no hum.  Just the popping, which is a bit too loud for my taste, and which is frustrating.  It happens with two different preamps (Ayre and Placette).  It is much louder than the "turn off" popping that I get with my Bryston, but similar in "sound" which is why I was wondering if it might somehow be the amp.

[James Tanner]

There is no longer a ground loop.  The issue is popping when switching inputs.  Specifically the "pass through".  The ground loop was one possibility, but that has been eliminated.  Everything is plugged into a single dedicted 20A outlet, and it is just the amp, a CD player, and a preamp.  Everything else has been unplugged and disconnected (including disconnecting the cable from the unpowered cable box).  There is no hum.  Just the popping, which is a bit too loud for my taste, and which is frustrating.  It happens with two different preamps (Ayre and Placette).  It is much louder than the "turn off" popping that I get with my Bryston, but similar in "sound" which is why I was wondering if it might somehow be the amp.

Email Mike at Bryston and he may be able to help - mpickett@bryston.com