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Pink noise whine hiss on Levinson 333

Please help. My ML333 amp makes a pop sound on the speakers when switch to ON from Standby -- I can hear the relays clicks inside the amp then follow by the pop (sometimes it pops going to Standby from ON). Worse yet, when it's IDLE (amp ON but not playing music) I can hear the amp puts out pink noise on the upper-mid and high drivers (my guess is 2kHz and up) when I am 2 feet away from the speakers. The noise is there with or without the preamp connected. Does anyone know what are the problems? It shouldn't be the from the main power line because I don't get this problem on my Denon home-theater receiver. Thanks in advance.
krellcast
6 responses Add your response
jon_p
46 posts
 
I had a very similar problem with 2 ML 436's I'd purchased. they did everything your amp is doing. I would have the pink noise sound as well as the popping sound. I would even have the popping sound when it was in idle sometimes. It took forever to finally realize it was the amps. The dealer & I thought it was anything but the amps. Also problem was intermittent so it was hard to trace. After figuring out it was the 436's the dealer sent them back to Levinson & they replaced them. We have yet to find out the problem. The new 436's work great & i havent had one problem from them.

Jon
onhwy61's avatar
onhwy61
5,218 posts
 
Contact ML's service department.
krellcast OP
2 posts
 
Plato -- I still got the problems after I've left it unplugged overnight. Sdcampbell -- the noise hiss is there even when nothing is connected to the input of the amp. I will try a cheater plug tonight (floating ground).
sdcampbell
2,136 posts
 
Hi, Krellcast. I have had a similar problem, and just made a post on the subject. See my post above titled "Grounding Problem with Adcom GTP-760".
plato
1,543 posts
 
Regarding my earlier advice, maybe you should unplug for 5 minutes or more because the ML 333 probably has a lot of power supply storage capacitance.
plato
1,543 posts
 
I don't know about the relay pop, you may want to make sure that the amp and AC outlet it's connected to are properly grounded. Beyond that, if the amp produces audible hiss without the inputs connected and the speakers aren't super high efficency models, then you'll need to send it back for servicing. There may be an internal problem. Try pulling the AC plug and then repowering the amp after about a minute. Sometimes that will allow the regulators to reset, which might get rid of the noise.
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