Amp heat sinks are ringing

Labtec: I deal with electrical tape every day. There are various grades that hold up to varying degrees over time. Some of this stuff won't even stick to itself after a while. Either way, i will GUARANTEE that putting tape on the heatsink fins of a high bias amp will end up leaving "adhesive gunk" on them. This is true even if you use something like 3M brand tape, which is good tape.

If you were to use something along the lines of high voltage / high temperature tape, that is another story. The problem with this is that, if you had to resort to using this type of product, the amp is already running hot. As such, adding such a compound to the heat sinks will only reduce the already limited convection that is taking place. Not a good thing.

As far as the 176* spec that you quote, what time period is involved in this level of exposure and how long is the tape supposed to hold up after being exposed to this type of temperature ? Sean
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PS... Would you like to hear from a manufacturer regarding "horror stories" that involve heat build-up and carpet being melted into the heatsink fins ?

Gnobber--

Let us know what Classe says-- the last time I emailed them a question, it took about a day and a half until a very helpful guy called me up with a reply.

As for my amps, I can make the heatsinks ring if I run my finger on or across them, but due to the lucky fact that they're sort of "buried" in my room and off to the side, I'll never hear the noise they make. Playing the system as loud as my loudest ever is I couldn't hear any appreciable ringing with the naked ear or a mechanic's stethoscope. I'll damp them with something anyhow, likely a rubber/cork/rubber sandwich pad used for electric motor isolation cut into little pucks. I have to talk to the sales rep and see what density he thinks would work best in this non-standard app of his products.

I wonder if one of Herbie's products (Hal-o) could be cut to work for you. They are at least tube-heat proof. I've never used them to hear how effective they are, but others seem to really like them.

Yours are not the only amps with this problem; at a shop long time ago, I had clapped in an audition room to check for slap echo. Something else was ringing - metallic, too. After a few test claps to narrow down who was talking back, we found a pair of Mark Levenson ML-2s on the other side of the room with some huge, lively heat sinks.

Good Luck!

To Pmkalby:

I received a reply from Armin at Classe, who says

"We have done some testing with regards to this concern, and I can tell you that the ringing is Not transposed into the sound from the speakers.

It is also very difficult to make the heatsinks ring when playing music unless the CAM-200 is directly in front of the speaker, and even in that scenario the ringing is very limited, and is not transposed to the speakers."

Nonetheless, I did cut up some wine corks into small trapezoidal wedges, and pushed them into the top and bottom of each heat sink pair. It seems to cut down the ringing when I clap, and has so far survived a loud listening session where the amps got quite hot. There is still a substantial airflow path to allow convection to work. This should take care of any noise that might have come through the amp and speakers, as well as any ringing that comes straight through the air to me.

thanks again for everyone's great ideas on this question!

Excellent idea Gnobber, I would continue to acquire wine corks. Even if it doesn't stop the ringing you won't care!