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Thread: ISOLATION Amplifier Suggestions

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    Default ISOLATION Amplifier Suggestions


    I have three HT amps; B&K 700.2, Fosgate Audionics 5002 and a Cinepro 3k6 Pro.

    I know I have noisey AC but the B&K 7-ch amp shows no sign of AC ground effect while my Cinepro and Fosgate both do... to an extreme degree. With those two amps plugged in, I get a significant humm through my subs and speakers.

    Tried to isolate the problem with both and had no success. So now I'm condsidering buying an isolation transformer to clean up the AC and get the same performance as the B&K for all three amps.

    AC conditioners I've seen are the Monster Power AC Regenerator, Richard Gray's high-quality (and pricey) subStation, or something most subtle like Tripp Lite IS250 250W Isolation Transformer, B+K Precision Isolation Transformer BK TR-110 ISOPACK, or Toroid Medical Grade Isolation Transformer ISB-030A. All of these look to be quality, can I achieve my goal without spending too much $$$.
    Last edited by AudioLib; 12-19-2011 at 07:19 PM.

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    Default Re: ISOLATION Amplifier Suggestions

    Quote Originally Posted by AudioLib View Post
    AC conditioners I've seen are the Monster Power AC Regenerator, Richard Gray's high-quality (and pricey) subStation, or something most subtle like Tripp Lite IS250 250W Isolation Transformer, B+K Precision Isolation Transformer BK TR-110 ISOPACK, or Toroid Medical Grade Isolation Transformer ISB-030A. All of these look to be quality, can I achieve my goal without spending too much $$$.
    Is there any reseller close to you where you could borrow them for a few days trial?

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    Default Re: ISOLATION Amplifier Suggestions

    This sounds like a ground loop rather than anything having to do with noise on the AC line, in which case an AC line conditioner is unlikely to do you any good. You most likely will need isolators in the audio lines, e.g., http://www.jensen-transformers.com/iso_aud.html.

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    Default Re: ISOLATION Amplifier Suggestions

    Definitely a ground loop prob. Still don't understand why my B&K is invulnerable to it.

    Guess I'm not clear on why a AC line conditioner won't solve the problem?

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    Default Re: ISOLATION Amplifier Suggestions

    Just a Best Buy. The death of Tweeter Etc. made them to only local AV supplier of note. Pretty sure they won't let me walk out with isolation unit.

    By the by, my wife worked for Russound and I was able to take the Fosgate to their lab for a test and it was dead silent through an isolation xformer. Maybe I should see if I could borrow that over a weekend to try at home? Hmmmm...

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    Default Re: ISOLATION Amplifier Suggestions

    Quote Originally Posted by AudioLib View Post
    Just a Best Buy. The death of Tweeter Etc. made them to only local AV supplier of note. Pretty sure they won't let me walk out with isolation unit.

    By the by, my wife worked for Russound and I was able to take the Fosgate to their lab for a test and it was dead silent through an isolation xformer. Maybe I should see if I could borrow that over a weekend to try at home? Hmmmm...
    That would be great if they did. I was kinda thinking it was a ground loop issue too, it is a bitch tracking this kind of stuff down, so being able to borrow one like evil suggested would be a good idea. Shoot maybe try and ac line conditioner from best buy or something just to see if it works, if not you can take it back.
    Magnepan, B&K, Emotiva, HSU

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    Default Re: ISOLATION Amplifier Suggestions

    Are they all plugged into the same outlet/circuit? (guessing not)

    Can't hurt to go buy one of those little LED circuit wiring checkers to be sure they are wired correctly, and that the ground is wired.

    Also, if they are plugged into power strips try and bypass them.

    Also, see what else is on the circuits you have them plugged into and unplug other devices from the circuit to see if you have anything going on with them.

    Ground loops usually come from having your sources/amps on different circuits though, and sometimes there's no way around that.

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    Default Re: ISOLATION Amplifier Suggestions

    Quote Originally Posted by AudioLib View Post
    Definitely a ground loop prob. Still don't understand why my B&K is invulnerable to it.

    Guess I'm not clear on why a AC line conditioner won't solve the problem?
    The way a device is grounded internally can affect its chassis potential. You get ground loops when ground potential is different between two different components, which in turn is affected by how circuits are grounded internally and how the component is grounded externally. Satellite and cable boxes are common sources of ground-loop problems, because they are wired to antennas or cable lines that have grounds separate from the home's electrical-service ground. Also, if the components are plugged into two different AC circuits, or even two different outlets, it may cause trouble. The reason a line conditioner won't help is that it doesn't affect any of that stuff.

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    Default Re: ISOLATION Amplifier Suggestions

    Quote Originally Posted by MDRiggs View Post
    The way a device is grounded internally can affect its chassis potential. You get ground loops when ground potential is different between two different components, which in turn is affected by how circuits are grounded internally and how the component is grounded externally. Satellite and cable boxes are common sources of ground-loop problems, because they are wired to antennas or cable lines that have grounds separate from the home's electrical-service ground. Also, if the components are plugged into two different AC circuits, or even two different outlets, it may cause trouble. The reason a line conditioner won't help is that it doesn't affect any of that stuff.
    Am I correct in parsing terms like line conditioner and isolation transformer or AC regenerator? A power conditioner doesn't do all that an isolator or regenerator can do, do they?

    I'm currently targeting a Panamax 5500 which appears to be a AC regen unit of note that could isolate my Cinepro.

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    Default Re: ISOLATION Amplifier Suggestions

    Quote Originally Posted by AudioLib View Post
    Am I correct in parsing terms like line conditioner and isolation transformer or AC regenerator? A power conditioner doesn't do all that an isolator or regenerator can do, do they?

    I'm currently targeting a Panamax 5500 which appears to be a AC regen unit of note that could isolate my Cinepro.
    I would use "power conditioner" as a catchall term for all such stuff. Anyhow, I doubt any of them will help if you have a ground loop (when all is said and done, the conditioner connects to house ground at the AC socket). Unless you have a very noisy power line or really crummy power supplies in your gear, there's seldom any point in anything more elaborate than a good surge suppressor. Things I think actually could help:

    1) Balanced connections to the power amps, if feasible.
    2) A ground isolator designed specifically for cable or satellite receivers between the cable or dish feed and the input on the box. (Such isolators have to be designed with extended high-frequency bandwidth so as not to block part of the signal.) Cable and satellite boxes are very common causes of ground loops, at least when there's any sort of RCA connection to the rest of the system.
    3) Isolation transformers in the signal lines to the power-amplifier inputs.

    You may find other useful advice on the Web. If you are going to get the power conditioner anyway, you might as well give it a shot before doing anything else, but I'd be surprised if it were to help with this particular problem. Here's a link to the most useful and authoritative tutorial on ground-loop elimination I know of: http://www.jensen-transformers.com/a...%20seminar.pdf; see especially section 5.4.

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    Default Re: ISOLATION Amplifier Suggestions


    I live out in the Metropolis of East Bend NC. I would go to the local hardware store $14.95 for a 6' grounding rod. Find out line isn't giving you problems, run the line out to a small breaker box, ground it out there and it's a pain and requires a bit o work, but worked great for this old hick. Best of luck buddy...

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