[Diamond Dog]

James :  Installed my new BIT 15 in my system tonight and it has actually made my system noisier. There is now a hummy buzz emanating from the left channel only. I thought it sounded like a ground loop issue. I tried a cheater on the amp driving the left channel- no better. What does resolve the issue is unplugging the amp runnning the left channel from the BIT 15 and plugging it into the wall ( same receptacle and circuit as the BIT ) - this also makes the BIT quieter as well - it hums / buzzes when that amp is plugged into it. The only things other than the amps ( 7B SST2 ) plugged into the BIT are a BCD-1 and my preamp ( Manley Jumbo Shrimp ) but even if I remove those components from the system, as long as the amp running the left channel is plugged into the BIT, the hum / buzz is there. Your thoughts?

D.D.

[James Tanner]

James :  Installed my new BIT 15 in my system tonight and it has actually made my system noisier. There is now a hummy buzz emanating from the left channel only. I thought it sounded like a ground loop issue. I tried a cheater on the amp driving the left channel- no better. What does resolve the issue is unplugging the amp runnning the left channel from the BIT 15 and plugging it into the wall ( same receptacle and circuit as the BIT ) - this also makes the BIT quieter as well - it hums / buzzes when that amp is plugged into it. The only things other than the amps ( 7B SST2 ) plugged into the BIT are a BCD-1 and my preamp ( Manley Jumbo Shrimp ) but even if I remove those components from the system, as long as the amp running the left channel is plugged into the BIT, the hum / buzz is there. Your thoughts?

D.D.

Hi DD

You have 7B's?

James

[Diamond Dog]

 I do indeed, James. And they're very nice, thank you. 

D.D.

[James Tanner]

I do indeed, James. And they're very nice, thank you. 

D.D.

Ok that is the issue - the 7B's already have the BIT type transformers built into them and they are drawing too much current.  The amps should plug directly into the wall and everything else into the 15 amp BIT.

james

[Diamond Dog]

Ok that is the issue - the 7B's already have the BIT type transformers built into them and they are drawing too much current. 
james

Even at idle, the 7's are drawing too much current? The hum is there at idle. 
Also, why only humming in the left channel?

D.D.

[James Tanner]

Even at idle, the 7's are drawing too much current? The hum is there at idle. 
Also, why only humming in the left channel?

D.D.

Hi DD

I find with the large amplifiers that the current draw on the Torus or BITs even at idle will cause the internal transformer to hum.

james

[srb]

I find with the large amplifiers that the current draw on the Torus or BITs even at idle will cause the internal transformer to hum.

If I understand Diamond Dog correctly, the hum in one channel is hum through the speaker, not mechanical hum in the BIT transformer?
 
Steve

[James Tanner]

If I understand Diamond Dog correctly, the hum in one channel is hum through the speaker, not mechanical hum in the BIT transformer?
 
Steve

Hi Steve - I thought he was referring to mechanical hum in the transformer in the BIT

james

[95Dyna]

I have a pair of post 01825 7B SST2's and have had them plugged into my Torus CS15 (same unit as the BIT15) for 1.5 years and have never had any hum or noise in either channel.  In fact, I like the sound slightly better than plugged into the wall.

[Diamond Dog]

If I understand Diamond Dog correctly, the hum in one channel is hum through the speaker, not mechanical hum in the BIT transformer?
 
Steve

Thanks Steve. It's both actually ( the transformer and through the system into the left speaker ).

D.D.

[Diamond Dog]

I have a pair of post 01825 7B SST2's and have had them plugged into my Torus CS15 (same unit as the BIT15) for 1.5 years and have never had any hum or noise in either channel.  In fact, I like the sound slightly better than plugged into the wall.

Dyna : Thanks! I was so hoping to hear from you on this...I remember reading your posts when you first got your Torus and noting that we had similar set-ups.
I spoke with Mike Pickett today - the Bryston boys are on the case.

D.D.

[werd]

James :  Installed my new BIT 15 in my system tonight and it has actually made my system noisier. There is now a hummy buzz emanating from the left channel only. I thought it sounded like a ground loop issue. I tried a cheater on the amp driving the left channel- no better. What does resolve the issue is unplugging the amp runnning the left channel from the BIT 15 and plugging it into the wall ( same receptacle and circuit as the BIT ) - this also makes the BIT quieter as well - it hums / buzzes when that amp is plugged into it. The only things other than the amps ( 7B SST2 ) plugged into the BIT are a BCD-1 and my preamp ( Manley Jumbo Shrimp ) but even if I remove those components from the system, as long as the amp running the left channel is plugged into the BIT, the hum / buzz is there. Your thoughts?

D.D.

Hi

when you say removed components do you mean just off or unplugged with no cabling?.  Does that amp buzz into the other speaker?

[Diamond Dog]

Hi

when you say removed components do you mean just off or unplugged with no cabling?.  Does that amp buzz into the other speaker?

Hi Werd : All components disconected from system - IC's unplugged from amps and components unplugged from BIT 15. The buzz / hum is only coming through the left channel speaker. Here's a list of what I tried and what happened :

 The equipment associated with the BIT in the system is: BCD-1, Manley Jumbo shrimp pre-amp ( tube ) and two  x 7B SST2 ( s/n 2177 & 2178 so both have new-style transformers etc.). System is installed on a Target stand w/ BCD-1 on top shelf, pre-amp on second shelf, 7B driving right channel on third shelf, 7B driving left channel on fourth shelf, and BIT 15 on bottom shelf. Amount of space between BIT 15 and nearest 7B is 8". Here is what we learned ( all equipment other than amps, speakers and BIT removed from system ) -

a) With amps plugged into BIT and BIT plugged into wall socket I have always used for this system

- w/ BIT on and amps powered down - no noise

- w/ BIT on and right channel amp ( furthest away from BIT ) on, audible buzz / hum from BIT, No audible hum from speakers L or R.

- w/ BIT on and left channel amp 8" above BIT ) on - audible buzz / hum from BIT and audible hum from let channel speaker.

- w/ BIT on and both amps on - BIT hum /buzz more pronounced & audible from listening position, more pronounced hum from left channel speaker also audible from listening position.

It should be noted that the amps are idling with source and pre-amp removed from system so current draw would be minimal. 

As controls, the following tests were done:

- All tests from a) were repeated but with system plugged into a completely different circuit. Results were the same as above.

- Finally, with all equipment involved in the testing returned to orignal circuit and powered up, I tried to move the BIT as far away from the amps as the power cords would allow. Buzz / hum from both the BIT and the left channel speaker were reduced ( but not eliminated ). This would appear to indicate that the BIT is interacting with the amps in a negative way ( magnetic fields? ). Clearly it does not get along well with its playmates.

With the BIT 15 out of the system and the amps plugged into the wall, the system is dead quiet.
If you have any input, I'm all ears.

D.D.

[werd]

Hello DD

I have my 14B right next to my Torus 20 and nothing like that. I did get more buzz related to my tube pre amp but it was there to begin with. Changing power cabling into my pre amp brought the buzz down. What  power cables are you into the power and bit?

[Diamond Dog]

Hello DD

I have my 14B right next to my Torus 20 and nothing like that. I did get more buzz related to my tube pre amp but it was there to begin with. Changing power cabling into my pre amp brought the buzz down. What  power cables are you into the power and bit?

Hey Werd :  All power cables are OEM.

D.D.

[werd]

Hey Werd :  All power cables are OEM.

D.D.

Move you power cables around for trial and error. Also try switching the amps. Move the cabling or move the amps but try using the amps on different channels and see. You will find out if its in the amps or bit this way.

[Diamond Dog]

Move you power cables around for trial and error. Also try switching the amps. Move the cabling or move the amps but try using the amps on different channels and see. You will find out if its in the amps or bit this way.

Hey Werd : I have swapped out power cables first between the amps and then between the BIT and the amps - no improvement. Then swapped speaker cables between amps to see if hum would migrate - no deal. I think the BIT will be heading east because it apparently has already gone south...Thanks for the help! 

D.D.

[James Tanner]

Hey Werd : I have swapped out power cables first between the amps and then between the BIT and the amps - no improvement. Then swapped speaker cables between amps to see if hum would migrate - no deal. I think the BIT will be heading east because it apparently has already gone south...Thanks for the help! 

D.D.

Hi DD

Did you get my email about returning the unit so we can have a look?

james

[Diamond Dog]

Hi DD
Did you get my email about returning the unit so we can have a look?
james

I did, James and thank you. It looks like I've exhausted all possibilities in terms of what it could be other than a potential issue with the unit itself. I don't want to waste anybody's time out at Bryston if the noise problem isn't actually related to the unit but I'm pretty much out of ideas on this end...I'll touch base with Mike on Monday and unless he has any other ideas, it'll be on its way back for you folks to check out. Thanks for following up!

D.D.

PS : I love what it does for the system and am really looking forward to getting this resolved and getting this unit back into the rack. The new faceplate looks good,too.