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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 3 responses by whyt_rabbit

whyt_rabbit OP
20 posts
 
Last night I switched speakers and the high pitched noise continued, so it definately isn't the speakers.

Additionally, I got the same "Poping Static" sound when shutting down the units with the other speakers.

This is definately a amp/pre-amp issue.

I'm getting a new set of tubes for the CJ and I'll see what difference these make in the "high pitched whine". I'm glad to hear that others think it is the tubes.

What about the shutdown noise, could this also be caused by the tubes???
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.
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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