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DC leakage from power amps

I am hoping to get some advice on how to check for dc leakage from my power amps. I have a pair of Bryston 28B SST2 mono blocks, powering a pair of Wilson Maxx2's. The Wilsons drivers are protected by resistors, acting as fuses. I have been blowing quite a few of the mid driver resistors, valued at 5.8 ohms. Last night I lost another mid resistor cluster on my left channel ( there are 4 wired in a series/parallel configuration), and what I thought was a tweeter resistor, but upon replacing that single resistor (4.2 ohm) with a fresh one, still no tweeter. I was fed up, and did not investigate further, but fear that I may have a dead tweeter, or worse, crossover issues. I am no tech expert, but am concerned that I may have DC leakage from my Brystons. I live about a 4 hour round trip to the Bryston facilty in Peterborough Ontario, and have lots of warranty left, but don't want to pack up the beasts and have them inspected if I can confirm on my own, if there is a DC issue. How do I go about checking the amps at home, and confidently knowing if there are amp issues, or not. If the amps are faulty, I will return them for repairs, but would like to eliminate/confirm the issue at home. Any help will be greatly appreciated.

crazyeddy
crazyeddy's avatar
crazyeddy OP
347 posts
 

@jea48  I  do indeed have 2 dedicated 20 amp circuits, and am fortunate to have my main panel box in my listening room, in fact, from my panel box to my outlets is a direct vertical drop of approx. 4 ft , and yes #10 awg. None of my power cords are stock. All are AudioQuest NRG-4's, and all are either 3 ft, or 6 ft.

Power out of my conditioners is a rock solid 120v, although I have not checked this under high volume conditions.

It all just may be that I am the culprit here. Herman makes a good point, that it may be louder than I realize. After so many years of working in extremely loud industrial settings (metal fabrication) and add to that my years as a hard rock guitarist, some hearing loss may be more than I realise. I do have a SPL meter, but haven't used it in years. Perhaps I will dig it out of storage and see what actual values are being presented in my room. Will follow up with these readings tomorrow.


Thanks all.......

jea48
2,944 posts
 
Power out of my conditioners is a rock solid 120v, although I have not checked this under high volume conditions.

Power conditioners? Them must be some big honken power conditioners.
What is the KVA rating of each power conditioner?

What is the quality of the receptacle the amp/s are plugged into on the output of the conditioners? There is where, at the receptacle, you need to check for VD.

Have you tried plugging the amps directly into the wall outlets?
With #10awg wire 4ft long from the main electrical panel, the power available for short quick draws of current could be well over a 100 amps. More than enough current available for the amps. The 20 amp breakers protecting the #10awg wire will pass quick short draws of current all day long with out tripping. (I assume the electrical service is at least 100 amps or 200 amps. Check the main breaker handle rating.)

The SPL meter sounds like a good idea.

Jim
atmasphere's avatar
atmasphere
7,068 posts
 
The SPL meter sounds like a good idea.
I think that would be a good idea too.
geoffkait's avatar
geoffkait
14,147 posts
 
The terrific thing about using a SPL meter is that you discover just how many pressure peaks there are in the room, including out in the 3D space of the room. You know, peaks that are say, five to ten times higher than the average sound pressure level in the room. Hel-loo!

crazyeddy's avatar
crazyeddy OP
347 posts
 

@geoffkait 

Careful there Geoff you mentioned 3D. Bo might me listening!!!

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