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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
whyt_rabbit OP
20 posts
 
Well, I'm at home now and I'v had just the amp powered on for almost 1 hour (and nothing else - per Kr4 suggestion). NOTHING!! Pure silent blissful darkness.

Good, it's not the speakers and it's not the amp. That leave ole' Connie J in the hot seat on the high pitched "whinning". I'll have to get some new tubes first, but hopefully that will solve both issues.

However, I still get a "zipping" sound when I shut down the amp (with nothing else on). Could this still be caused by bad tubes even with the pre-amp powered off??

I have two distinct sounds on shut down. The amp makes a zipping sound and the pre-amp makes a "popping" sound. Each are separate sounds and independant of each other and other components or what is on or off when turning these components off. Both sounds only come out of the right channel.

I'll try to roll the tubes and see if the sounds switch sides. Stay tuned and thanks for your help so far.
swampwalker's avatar
swampwalker
5,138 posts
 
After you get the new tubes, if you still have a problem you might drop an email to Steve McCormack at SMcAudio (get the address under manufacturers. He's usually pretty generous with his time, although sometimes when he's travelling it takes a while to get a response.
kr4's avatar
kr4
3,691 posts
 
Also try swapping the ICs. And I second the suggestion to call Steve at SMc.
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.
whyt_rabbit OP
20 posts
 
Thanks everyone for all your help.

I'm still getting the "zipping" sound out of the right channel of the amp on Powerdown, no matter what I do (including the tube rolling) so I'll be calling Steve. Actually, that is one of the reason's I bought a McCormack, I saw his response to a couple of threads here and decided that I wanted equipment with a guy who took the time to answer his customers. It probably is the "mute" issue talked about above, but now I might as well upgrade if I end up shipping the unit back to him. He He He...maybe this is a blessing in disguise. I don't get the "popping" once the amp is shut down and the power drains off, if I wait a few seconds to shut down the pre-amp.

I just rolled the tubes and I'm waiting to see if that had any effect on the "Whinning". A couple were a little loose (probably from shipping) so maybe that was all it was. I'll let you know and if Ericd74 could keep me informed on his CJ i'd appreciate it. Nope, as I type this note, I can hear the "whinning" from the other room. Hope it is the tubes. Hey this new hobby of mine sure is fun!!!

Happy Listening.

P.S. I have no idea how old the tubes are (from a previous question and I have swapped out the IC's with Rat Shacks and it made no difference.
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