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Levinson turn-on thump... normal??

My dealer let me borrow one of his Levinson 431's (I am ampless at the momeny - looong story) to play with for the weekend.

I noticed that when I take it out of stand-by there is a horrible turn-on thump that comes through the aerials. This happens even when there are no single ended connectors attached (ie no input thumps which could be coming from my Unidisk pre-amp). It's really unpleasant and I'm afraid it's going to damage the 10T's. Is this normal with Levinson gear? I certainly didn't expect it.

I am using a single pair of speaker terminals which are firmly snugged down under the binding posts.

Another thing I noticed was that after the thump the woofer stayed in the "out" position. Not completely pushed out - but further out than it's typical "resting" position (amp off). It seems to only happen on one of the Aerials. I switched to the other channel of the Levinson and it still did it. Any ideas? Is it possible that the resting state is not the "neutral" position of the voice-coil?

Other than those two oddities I am in love with this thing. It really creates a 3 dimensional sound and everything just sounds "right". Bass response is absolutely stunning.

Thanks in advance.
jim_swantko
jim_swantko OP
301 posts
 
I determined that using the shorting pin for the balanced inputs will eliminate the thump. I tested my 336 and sure enough with the pins removed I would get the thump... with them in it was quiet.

That's what I get for using single-ended inputs I guess! :)
redwoodgarden
150 posts
 
I have two 334 Mark Levinson amps. One thumps when turned on and off, and the other one does not. Strange! I sent back the one that thumps, and they returned it saying that it meets all accepted specifications...but it still thumps!!! I guess it is something that we will have to live with.
stereoman
3 posts
 
My Levinson 332 (when it worked properly) didn't "thump" coming out of STANDBY, but it did emit small pops and clicks through both speakers. I was told this was normal.
jmrdc
4 posts
 
My 331 emits a few "cricket" like clicks and some low level thumps that the manual says are "normal and not harmful."
stereoman
3 posts
 
Follow-up to my 03-13-07 posting: My 332 went "belly-up" on me about 6 weeks ago. Although it still worked, there was a loud 60Hz hum in the right channel, and the pops and clicks evolved to really nasty transients in both channels, when going in and out of STANDBY. It's back at Levinson right now, getting completely overhauled.
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