Pass Labs cooling noise


 I have a recently purchased Pass Labs INT-60 that is making periodic clanking noise as it is cooling down on turn off.

My many previous non- Pass amps were always quite, Mac’s and  even my Parasound JC5.

Any ideas before reaching out to the dealer/company?

BTW the Pioneer S-1ex’s sound amazing with this setup with the OS Audio Directstream and Oppo 205.
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Wouldn't worry too much about it, it sounds like it's just the tinkling sounds, different rates of contraction of the heatsink (alloy) that bolted to the chassis.

Cheers George  
I have this amplifier and it does make noise when cooling. I never turn it off except for system changes. It sounds better when always left on.
Putting in a Synergistic Research Blue fuse makes a nice improvement and is a one minute job.

David Pritchard
FWIW, my x250.5 and my current XA60.8s made that kind of noise on cool down.  I talked to both the dealer and to Passlabs both said don’t worry.
Post removed 
OK.   NOT worrying.
thx for input.
Ever heard a house heating duct clang and bang mid winter when it’s belting out hot air and cooling. No different. Refractory lined cool systems are coming. Then again Class D is an efficient bulldozer. I can only afford late 90’s tech but it’s a pretty sweet ride. 
X350 does the same think. I assume it's because the heatsinks are structurally part of the chassis and cool at a different rate. 
Agreed. You can't stop metal from expanding and contacting as temperature changes... a simple fact of nature.

Just make a call to Pass to see if this is the norm.  If Peter is still at Pass, ask him.


I have called Pass about the noise on my amp and they said it is normal while warming up or cooling down to hear the clinking just the heat sinks contracting and expanding