[carlos3621]

what is the remedy for ac/line noise??

i went from having a b/k components receiver to bryston powerpac 120 amps,
that setup also had a bit of ac/line noise, but was easily fixed, by lifting the ground loop switches that were on the bryston powerpacs.

I now have the bryston sp 1.7 pre/  with balanced interconnects going to the bryston 9BSSST  amp. im now back to having line noise issues.. except this time, the new bryston amp does not have a ground lift switch?!!
any help would be appreciated.
thanks in advance!

[brucek]

except this time, the new bryston amp does not have a ground lift switch?!!

Since the SP1.7 and 9BSST both have their own safety grounds, I see no problem with lifting the shield connection of the balanced interconnects at one end. This would solve the problem if that's where the difference potential originates.

brucek

[ec]

I would try to find the source of the problem (probably cable TV or the like).  I would attach only the SP 1.7 to the 9BSST.  In otherwords don't plug anything into the SP 1.7.  If the hum still occurs - it is something in the AC which hopefully can probably be traced to another item on the same circuit.  If no hum, start attaching your source components one by one until you find the culprit.  Once you find the culprit take the necessary action which may include things like the Mondial Magic Box if the problem is with cable

[Bob Reynolds]

I didn't think balanced lines were susceptible to ground loops since the signal isn't relative to ground.

I would look at whatever unbalanced connections are in your system.

Visit the Jensen Transformer site for safe solutions: http://www.jensen-transformers.com/

[carlos3621]

i have eliminated everything except for the 9bsst and sp 1.7.
if i unplug power cord to the sp 1.7 and turn on the amp... still hums.
if i  unplug the interconnects between the 1.7 and the 9BSST ,
and turn on the power to the amp,,  NO HUM.
so im assuming its a ground loop between the preamp and the amp, through the balanced interconnects. How do i go about lifting the ground on the interconnects, wich pin do i unplug ??     
or is there an ac line conditioner that i can use , that wont diminish the sound ?

thanks guys!!

[brucek]

How do i go about lifting the ground on the interconnects

Pin 1 is the shield. Disconnect it at the amp end. Leave it attached at the preamp. If the hum goes away it tells you there was a small potential difference flowing between the two chassis. Both chassis are safety grounded, so you're fine.

brucek

[DSK]

This may be a stupid question but ... in this sort of situation, could it help to run a ground wire from the chassis of one component to the cassis of the other component (eg. mounted with a ring connector on each end fastened under a chassis screw)?

[Bob Reynolds]

i have eliminated everything except for the 9bsst and sp 1.7.
if i unplug power cord to the sp 1.7 and turn on the amp... still hums.
if i  unplug the interconnects between the 1.7 and the 9BSST ,
and turn on the power to the amp,,  NO HUM.
so im assuming its a ground loop between the preamp and the amp, through the balanced interconnects. How do i go about lifting the ground on the interconnects, wich pin do i unplug ??     
or is there an ac line conditioner that i can use , that wont diminish the sound ?

thanks guys!!

If I understand your 2nd sentence correctly, you only have the 9B plugged into the the AC source, but still have the balanced cables connected to the 1.7. If that's the case, how can there be a ground loop when only one component is connected to ground?

Did you disconnect the balanced cables one by one or all at time? From what you're describing I'd guess one of the balanced cables is bad.

[Audio-den]

UNPLUG THE PSA AND GO INTO WALL DIRECT GOOD LUCK ALAN

[ec]

if i unplug power cord to the sp 1.7 and turn on the amp... still hums.

Not good enough.  Unpluggiing the power cord will not suffice IMO because the interconnects are still attached including the ones to the source components via the SP 1.7.  They share a common ground.  You need to unplug all the source components (and yes leave the SP 1.7 power cord plugged in so you can turn on the SP 1.7 and 9B SST.

[carlos3621]

 "Not good enough.  Unpluggiing the power cord will not suffice IMO because the interconnects are still attached including the ones to the source components via the SP 1.7.  They share a common ground.  You need to unplug all the source components (and yes leave the SP 1.7 power cord plugged in so you can turn on the SP 1.7 and 9B SST. "


Eric, i only have one source component,,, and it is connected via optic cable.,
so i have eliminated the source components.
 im going to try pluggin in one balanced connection at a time , to eliminate a possible defective cable.

Alan, both  , the processor and amp are going directly to the wall plug.

Bob, i have looked at those jensen isolators,, (which would be my last resort), i want to try to keep any additional components  away, as i think they would degrade sound quality ?

overall.. i think bruce's idea is going to do the trick,,, lifting the ground from the pin 1  on all the balanced connections.

thanks for the help , much appreciated.

[John Casler]

What many sometimes don't understand is that there needs to be no seemingly "direct" connection between the components, and the cable/sat for the hum to occur.

Your amp only example might show that this is the case.

You must disconnect the RG6 cable for the sat/cable where it comes in on the wall jack.

Nothing else, will tell you if that is the problem.

If that cable is still connected, and it runs to the cable/sat box, and that box is plugged into the AC, you will get hum via the AC to any susceptible components. (SUBs, AMPs, etc)

[Bob Reynolds]

Bob, i have looked at those jensen isolators,, (which would be my last resort), i want to try to keep any additional components  away, as i think they would degrade sound quality ?

They must be good enough for Jeff Rowland. He uses them in most (if not all) of his amps and preamps. I use several in my system. http://www.jeffrowland.com/Technology/LineLevelTrans.htm

If it turns out to be related to your cable TV, Jensen has an isolation transformer for that as well. You can try cleaning and redoing the cable TV ground at the service entrance.

[Bob Reynolds]

What many sometimes don't understand is that there needs to be no seemingly "direct" connection between the components, and the cable/sat for the hum to occur.
.
.
.

If that cable is still connected, and it runs to the cable/sat box, and that box is plugged into the AC, you will get hum via the AC to any susceptible components. (SUBs, AMPs, etc)

John, are you saying that this is true even if the interconnect cables from the cable/sat box are disconnected?

[carlos3621]

thats interesting... john, your saying that the ac noise could be coming back to the ac line,,, from the cable box?,, i guess that does make sense though.
 since my amp/pro does not have its own dedicated line.

bob.. thats a very interesting article on the jensen isolators.. im a beleiver!! 

i havent yet done any more diagnosing with the system, as im in the middle of a move and had to pack up all my gear for the time being...

[John Casler]

What many sometimes don't understand is that there needs to be no seemingly "direct" connection between the components, and the cable/sat for the hum to occur.
.
.
.

If that cable is still connected, and it runs to the cable/sat box, and that box is plugged into the AC, you will get hum via the AC to any susceptible components. (SUBs, AMPs, etc)

John, are you saying that this is true even if the interconnect cables from the cable/sat box are disconnected?

YesSiree Bob,

The "hum" is also present and flows through the AC lines. That cable from the SAT/Cable "must" be disconnected at the wall so that "nothing in the room" is contaminated.

[carlos3621]

hello,

 sorry to revive this topic, im still trying to figure out the best way to eliminate my ac / hum noise heard.
ive finally moved into my new place, and still having noise issues, i disconnected everything, including the cable wire, noise still there,
then i disconnected all my interconnects, except for one, and i cut the ground wire off, but the noise still wont go away.
i guess im going to have to buy a ac power line isolator ?  which ones do you guys recommend?  (not too expensive).

thanks
carlos

[Oyama]

Carlos, have you made any progress eliminating the hum?

[Daniel Datchev]

Hi I am new to Bryston products.
In first days after New Years Day I received my BCD-1 and B100-SST.
With the first switch on I notice there is noise coming from the speakers.
I disconnect any connector from the amplifier but the noise still
presented. To check both CD player and Amplifier I switched each of them with
partner from my previous equipment.In both cases the noise still presented.
Which took me to conclusion that better detail from both Bryston units
let me to defind that the only issue for the noise is AC supply. I also disconnect the
ground lead in amp, but this did not change the situation.Now I understand why
people possesing quality equipment are using conditioners.With low level equipment
you can`t defind whether it`s a AC noise or equipment`s limits.
Any recommendation for conditioner working on 220V/50Hz ( German standart Schuko plug)
Daniel

[carlos3621]

update:  i kept my unbalanced interconnects , and continued to use them for about a month, with no "ground loop noise".
funny thing is,,, a couple of weeks ago, i decided to try my  balanced interconnects once again to see about that "ground loop noise/humming " that i was getting originally, and to my surprise the noise diminished to a negligible level! 
although comparing the two, with the balanced , i get the "clicking" noise heard through the speakers , whenever the digital signal is interuppted. (not a big issue, besides i can programm the sp 1.7 to lock on to a signal right?).
i dont know what to make of it, maybe the electronics/ capacitors..etc. had to be ran for a bit, and cycled.
i still would like to get an a/c quality line conditioner , to lower the noise floor (slight hiss at no volume).
anyways thanks to all for all the help  aa