[carlos3621]

hi,,,
  im wondering, which is the proper torus ac line isolator, to use for a 9bbst and an sp1.7  ?
the amp itself does not hum, only when i plug in the sp1.7 via interconnects.  (nothing else). can i get away with just an isolator for the sp1.7 ???
or am i going to have to plug in both , the amp and processor?

thanks
carlos

[James Tanner]

hi,,,
  im wondering, which is the proper torus ac line isolator, to use for a 9bbst and an sp1.7  ?
the amp itself does not hum, only when i plug in the sp1.7 via interconnects.  (nothing else). can i get away with just an isolator for the sp1.7 ???
or am i going to have to plug in both , the amp and processor?

thanks
carlos

Hi Carlos

The 15 amp Torus would be the unit I would recommend. My only concern is what is causing the hum when you plug in the SP1.7 to the 9B? 
Is the 1.7 connected to a TV Cable source?
Are you using RCA between the SP1. and the 9B or Balanced XLR?
Is the hum from all channels?
If you have no inputs and only outputs from the SP1 to the 9B does it still hum?

james

[carlos3621]

hi james,
thanks for responding,, 
heres what ive found out; 
i have unplugged all cable connections to all t.v.'s --- still hummin through all speakers
i unplugged all source inputs to the surround pro.---- still humms
i unplugged all interconnects except for left side-- still humms through left speaker
i disconnected left speaker interconnect, and substituted a rca type (non balanced), and hummin noise gone!,
if only the amp and speakers are connected and the processor is disconnected at the interconnects,,, no humm.

im guessin the ground loop is definately coming from the processor and amp connection , through xlr(balanced) connection only.
the humm noise seems to be ac power 50/60 cycle (type).
my xlr cables are brand new, and i purchaced through bettercables.com  (high quality wire and terminals).
i also have tried cutting the shield (ground wire) inside the cable, but hummin gets louder.

 i wouldnt care about the noise, as its barely audible, but ive gone through this problem with other components before, and when i fixed the humming, the noise floor improved and so did the sound, (very noticeable difference)..

thanks in advance for your help in resolving

carlos

[James Tanner]

HI Carlos,

Try 'floating' the ground pin on the power cord on the SP1.7 and then on the 9B - only one -- not both.

james

[John Casler]

Hi Carlos,

The cable comes into your house/apt via a "coaxial" (RG6) connector on your wall.

Disconnect that, and see what happens

Also, if "any" other cable comes in "any other" room in your house, disconnect it also "at the wall".

hi james,
thanks for responding,, 
heres what ive found out; 
i have unplugged all cable connections to all t.v.'s --- still hummin through all speakers
i unplugged all source inputs to the surround pro.---- still humms
i unplugged all interconnects except for left side-- still humms through left speaker
i disconnected left speaker interconnect, and substituted a rca type (non balanced), and hummin noise gone!,
if only the amp and speakers are connected and the processor is disconnected at the interconnects,,, no humm.

im guessin the ground loop is definately coming from the processor and amp connection , through xlr(balanced) connection only.
the humm noise seems to be ac power 50/60 cycle (type).
my xlr cables are brand new, and i purchaced through bettercables.com  (high quality wire and terminals).
i also have tried cutting the shield (ground wire) inside the cable, but hummin gets louder.

 i wouldnt care about the noise, as its barely audible, but ive gone through this problem with other components before, and when i fixed the humming, the noise floor improved and so did the sound, (very noticeable difference)..

thanks in advance for your help in resolving

carlos

[carlos3621]

john,,,,

i allready tried that,,, i unplugged every cable wire at the wall to every tv in the house,,,,
i eliminated that as being the problem.
i have basically got it traced down to the amp/ processor combo,,
the amp itself wont hum,,, its only when i connect it to the processor via the interconnects,
everything has been unplugged from the inputs to the processor,
the only thing that gets rid of it,,is when i use unbalanced connnections , but its noisy with balanced connections.
i just moved in,, so nothing is plugged in to the ac lines to be causing noise.
i even tried cushioning the chassis of the processor, so as to eliminate any possible chassis vibration.

thanks
carlos

[James Tanner]

Hi Carlos,

Try the floating ground and then try a different balanced cable.

It make no sense that the balanced cable would be noisier than single ended.

james

[carlos3621]

thanks for reply james,

i already tried eliminating the ground wire at the xlr interconnect,, it makes the humming noise louder.
i will next try a different brand of xlr, hopefully that helps..
ill will post tomm. on the results.

thanks
carlos

p.s. the current xlr's are high end with neutrik ends.

[carlos3621]

p.s.s.

the software on my sp1.7 is v43e

[carlos3621]

anybody??
im goin to next try some different xlr's and see if they also cause humm...
once again...  no humm with unbalanced interconnects...
humms with xlr's

thanks

[carlos3621]

update;

i tried different xlr connection and resulted with the same humming at speaker.

the problem is definately with the sp1.7  through the balanced ouputs only,, is this something that needs to be repaired??

thanks
carlos

[satfrat]

update;

i tried different xlr connection and resulted with the same humming at speaker.

the problem is definately with the sp1.7  through the balanced ouputs only,, is this something that needs to be repaired??

thanks
carlos

Did you try taking out (floating) 1 of the ground plugs as suggested? Using a floater plug works well. Also are all the outlets 3 prong and grounded to the same source (like a house grounding pole)?

[Phil A]

I use balanced outs on my SP1.7 to a 14BSST and a 6BSST with no problem.  Have you tried plugging them into a different circuit?

[satfrat]

I use balanced outs on my SP1.7 to a 14BSST and a 6BSST with no problem.  Have you tried plugging them into a different circuit?

That's where I was going with possiblly using different grounding sources on separate circuits.  Most homes have all their circuits using the same grounding source tho.

[Phil A]

I use balanced outs on my SP1.7 to a 14BSST and a 6BSST with no problem.  Have you tried plugging them into a different circuit?

That's where I was going with possiblly using different grounding sources on separate circuits.  Most homes have all their circuits using the same grounding source tho.

I just wanted to see if there was a chance it was just the receptacle (the std. builder's grade $ 0.35 ones suck and I not only change what I use for audio but what I use on a regular basis - the bathroom switches the builder put in practically fell apart in my hand when I changed those) or perhaps there is a dimmer or fluorescent on the circuit that might be the problem.  My 14BSST is plugged into a circuit that feeds a single receptacle.  I have my SP1.7 plugged into a Richard Gray unit which is plugged into another Richard Gray unit which is plugged into a Vansevers reference unit which is plugged into a different circuit.  I also have a bunch of PS Audio Noise Harvesters around.  My 6BSST (which drives the center and surrounds) is almost 20 ft. from my SP1.7 and it might be on a different circuit too vs. the SP1.7.   

The only component I have any hum with is in my seldom used basement system (I use it mainly to watch weekend sporting events during the day a couple of dozen times a yr. on my old 64 inch CRT) and is with an old NAD2100 amp I have strapped in mono on the center channel down there.  I moved the old Adcom 555 I had down there to drive the left and right in the bedroom system (which I used for more for background music but I use that system much more than the basement one).  I tried a couple of things and you can't hear the hum from 12 ft. away and the bar refridgerator makes more noise so I figured it wasn't worth my time.

[carlos3621]

thanx for the reply guys,,,

 i have allready tried the ac cheater plug,,, no difference.

i also tried cutting the the ground wire on the xlr plugs,,, made the humming worse.

the only thing that gets rid of the humm is using unbalanced rca type interconnects.....

[James Tanner]

thanx for the reply guys,,,

 i have allready tried the ac cheater plug,,, no difference.

i also tried cutting the the ground wire on the xlr plugs,,, made the humming worse.

the only thing that gets rid of the humm is using unbalanced rca type interconnects.....

Hi Carlos.

I guess it is time we had a look at the balanced output circuits on your processor.
Please contact Mike Pickett at Bryston.
mpickett@bryston.ca

One question - did the balanced outs work OK in the past?

james

[jethro]

Carlos:

Do you have another pre-amp that you could try ?

Are your 9B and SP-1.7 connected to the same circuit ?