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Zap Sound out of Speakers when Powering Off

I've recently put together a new system from fellow Agoner's and I'm going through a shake down right now. I have two problems and I could use some advice.

First the System:

McCormack DNA-1 Deluxe Amp
Conrad Johnson PV10a (with phono) pre
B&W 805 Naut's with Monster XP cables
Homegrown IC's Silver Lace
VPI HW19 JR TT
Phillips DVD/CD (crappie plastic IC)
XM Radio

First problem:

When powering off the pre-amp system, I get a loud static like "pop" from my right speaker. Then when shutting off the Amp It get a wierd "zip-zip" sound, again out of the right speaker. Is this normal when shutting down a two channel Hi-Fi system?? (speaker was slighly damaged on delivery - see below). Why is it only coming out of the right?? I'm waiting for DH Labs Q10 speaker cables, but it sounds more like a speaker or amp problem.

Second problem:

The system runs great and when the volume is turned all the way down it is very "black". However, after about 30 minutes or so of operation, it develops a very noticable high pitch "whining" sound out of the speakers. This seems to alternate between one of the two each time the system is powered up. You can hear it clear across the room when music isn't playing and it is almost at painful levels. I've shut down and turned off everything except the amp the pre and it still keeps "weeeeeeeeenn" Arghh!! Please help!!!

Note: The right speaker mentioned had a pushed in Tweeter cone when it arrived, but seems to be playing very well. It has a cracked tweeter case (very hard to even see) which lead me to think this might be the cause of both sound issues.

I haven't tried to swap out the speakers with something else to see if this is the cause (I'll try that tonight). Anyone have any ideas of what might be causing these noises??
whyt_rabbit

Showing 2 responses by ericd74

ericd74
18 posts
 
i recently had the same "popping" problem with my set up - plinius amp / CJ pre / cary CD / thiel 2.3...

this problem is often referred to as "motorboating" and is most likely the result of bad tubes in the pre amp (search for "motor boating" and "motorboating" in the tube section of audioasylum.com for more on this problem and possible solutions...

often times, replacing the tubes fixes the problem...i replaced my tubes, which fixed the problem for a few weeks, but then it came back. my pre amp is actually at the CJ factory now getting checked out.
ericd74
18 posts
 
as i wrote in my earlier post, i was having the same "popping" problem. i sent my CJ back to the company after changing tubes failed to solve the problem. they ran my unit for several days and didn't hear the popping noise, but then i spoke with them today, and they had heard it and were fixing it...i've only been speaking with someone in customer service, and he didn't know what the problem was, but i'll follow up and report back. i've found CJ helpful to deal with - i've had no problem getting in touch with customer service (Ed is the person i've been speaking with) and i've found him helpful and responsive. for what it's worth, i've also had excellent experiences with thiel's customer service in the past. certainly an advantage of buying from one of the smaller companies.
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