2. amps-preamps
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Popping from light switches and refrigerator

Help please! My amp just quit working and no one knows why! Two weeks ago the output light on my pre-amp burned out and there was no sound through the system even though the pre-amp tested fine when I sent it in for repair!

I just moved into a patio home (on a concrete slab) three weeks ago. WHEN the stereo actually works, the CD transport misreads and there's a pop out of the speakers when a light switch is flipped, the refrigerator door is opened or the refigerator cycles on.

I've had an electrical engineer look at it and said it was just line noise. I had an electrian come out last Friday and he couldn't find a reason. The three lines coming into the house were all tight and the breakers were all tight.

The light switches and refrigerator are on four different breakers. The electrician suggested running a dedicated line. The electrical engineer said that that wouldn't help since the switching noise seems to be bleeding through four different circuits now.

This happened (before the amp quit working) with both a tube pre-amp and solid state pre-amp. It happened with both a $2500.00 power conditioner and a UPS unit from my computer.

I lifted the ground on the transport, dac and pre-amp and the popping seemed to stop (for that day). The next day the power amp quit working altogether. I don't know what to do!

Chuck
krell_man
jeff_jones
418 posts
 
Jea48 - I really like the write up above, and think you may well be correct.
I'm still curious about the condition of the amp though. Chuck moved into the house 3 weeks ago, which makes me think that his audio equipment was moved and unaviodably bounced about at least a minor amount in the process at about the same time. Since the move there have been issues with all several components connected to a common circuit. So while I don't disagree with anything I've seen on this thread, it also seems like there is a chance that an intermittent high current draw from one of the audio components could cause similar issues. L dI/dT can be a bugger.

jea48
2,944 posts
 
Jeff, here is some great reading material. It explains in more detail just how a single phase center tapped secondary transformer works. Take note that the two single phase secondary winding leads, L1 and L2, are not 180 degrees out of phase with one another with reference to the centertap of the winding. One of the big selling points of balanced ac power systems.....Single phase in single phase out.
http://www.ibiblio.org/obp/electricCircuits/AC/AC_10.html

Jim
gtfsr
29 posts
 
I had the same problem in my apartment.
Thought about isolation transformers, power plants,
all the usually audiophile approved ideas.
Then I tried a ac line filter from a company
Sandy Gilman of Audio Den back in Stony Brook recommended.
elect-spec
http://www.elect-spec.com/acprot2.htm#Laboratory
Solved my poping noises.
GTF
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