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Not even an AC regenerator helps the hum

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In Reply to: RE: It takes 2 Humbuster III's in series to cure my hum. Is it ok to ... posted by Joeinid on March 05, 2010 at 18:32:16

Maybe I'll tag onto this thread, having the same problem.

I am having a hum problem too, Quad 909 and/or Quad 606 - and when my mingda tube preamp turns on into them, it sounds like a refrigerator.

Should a PS Audio P300 not solve this? I have a P300, and although I'd never run my 909 or 606 through it regularly, I thought surely it would solve the hum problem - to my surprise (and now great worry) it didn't. I didn't plug directly into the P300, I had an Ultimate Outlet which I plugged the amps into, then to the P300 (for no other reason than they wouldn't reach otherwise without a lot of rearranging).

Anyway, if there's a chance a humbuster will solve the problem where a P300 wouldn't, sounds like that's the horse to bet on?

Religion is the world's oldest profession

Follow Ups:

RE: Not even an AC regenerator helps the hum - PaulMC 06:00:40 03/10/10 (3)
Can you explain what you mean when you write that the hum only happens when the preamp turns on into them. Do you mean that if these amps are plugged in to the wall, turned on and connected to the speakers - but not connected to the preamp - they don't hum? Then you turn on the preamp and they do hum?

If that's the case I am confused and need clarity (probably true anyway!).

Please explain. Also, let me know if the hum is comeing from the speakers or the Quads themselves.
- RE: Not even an AC regenerator helps the hum - longtimequadowner 11:13:23 03/10/10 (2)
  I've done a lot of experimenting and get more confused with each experiment - never had this problem before!
  In all cases, the hum is from the speakers and never the amps themselves.
  If the 606 or 909 is on **without** the preamp there is a hum that is more like a light "buzz" that comes through the speakers, whether Quad 63's or LS3/5a's. So two amps, two speakers, identical results. This happens with and without power accessories - all situations. Audible from 10' away when all else is quiet.
  Now, when the tube pre is turned on the light "buzz" becomes a louder true "hum" more akin to a refrigerator level noise - easily audible from 10' away, probably even in the next room.
  To make things worse, with the Quad 909 - the light "buzz" becomes a louder "hum" even with the Quad 99 pre (which amazed me), and even when connected by the Quadlink cable. Maybe not as bad as with the tube pre but still quite audible.
  So in short the Quad 63's and LS3/5a's buzz with the 909 or the 606 even with no preamp, and both get a louder "hum" through the speakers with either preamp. The amps themselves seem quiet.
  I can start trying more amps of a less transformer heavy nature (the mingda also has a massive transformer and is tube regulated) - but the 909 is my amp of choice with the mingda, very heavenly combo.
  PS building is a 1956 condo, who knows what the wiring setup was and is today...
  
  Religion is the world's oldest profession
  
  Edits: 03/10/10 03/10/10
  - RE: Not even an AC regenerator helps the hum - PaulMC 15:22:39 03/11/10 (1)
    OK, that's very helpful. So, the Humbuster option is out. The PS Humbuster only helps with transformer noise which you apparently do not have.
    
    It sounds like you might have a light dimmer somewhere that's possibly causing the problem. It's hard to imagine that it's the amps themselves under the conditions you refer to. Generally, if the amps are sitting all by themselves plugged into a speaker, and there's buzz, you have a problem with the amps - but I don't know in this instance.
    
    Check for any light dimmers in the home first and let me know.
    - RE: Not even an AC regenerator helps the hum - longtimequadowner 16:50:56 03/11/10 (0)
      Ok thanks, it is something bizarre and yes there are in fact two light dimmers, would have never imagined anything like that being a cause. I tried a Meitner STR-50 last night with the same results.
      
      I'm pretty sure it doesn't happen with a Creek OBH12 passive though, I'll have to haul it out again but since I've been living here for 5 years now it's always been the OBH12 into a Quad 303 and then Quad 57's. When I started experimenting with ESL 63's I was using the Creek and don't recall any hum, certainly not any loud one of any kind with the STR50, 303, or 909. But when the mingda hooked up with thye 909 I knew my trials were over - short of the refrigerator sized hum of course.
      
      Thanks for your help, I'll experiment in the coming weeks...
      
      Religion is the world's oldest profession

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