Amp heat sinks are ringing

Hi everyone,

thanks for your many responses- there are a lot of interesting ideas out there!

To answer a few questions:

-the amps are on homemade stands (2 3/4" sheets of particle board, screws running through them to provide spiking to the the floor, screws extending ~1.5" beyond the particle board)

- the room is 20x27, speakers both on the 20' wall. Drywall construction, cathedral ceiling, berber carpet on the floor. The wall behind the speakers has around 16' of windows, 4' high (that is mostly what I was trying to cover with the temporary use of foam as an experiment)

-I have written to Classe about this yesterday- no response yet.

-I am not sure if the ringing is audible through the speakers. The ringing IS audible directly through the air (i.e. hand clap excited the heat sinks, they ring, and are audible 10 feet away).

thanks for everyone's help! At this point I think I will try some rubber (stoppers, bicycle tube) to see if that helps as a quick experiment.

Bill

Bill,

WOW, you have a lot of things going on in this room! Cathederal Ceiling will cause echo-ing.

First off your stand!!! Particle Board IS TOO DENSE!!!If you only have 4 screws going through the 2 pieces, then there might be vibration in the stand itself. Did you use wood glue to laminate the 2 boards together???

Lose the DIY Particle board stands, look into maple for a stand top. Stay away from metal, mdf, & glass! Metal bases are ok as long as they can be filled to be dampened. You just don't want the top to be metal.

16' of Glass, try heavy Drapes, or if older windows?
Look into (in time) replacing them w/ triple glazed, foam filled vinyl or wood windows, w/ argon gas.

Take apart the stands, glue them, & re-screw them w/ more than just 4 screws that hold the whole base together. Them get back to us about Ringing!

I agree with Audiobugged. It sounds like you've got a lot of work ahead of you. The ringing of the heatsinks is but a very small piece of the puzzle at this point in time.

My thoughts are that you should work with room acoustics first and then move in the area of your racks / stands. All of the sound bouncing around that type of room will overwhelm any system improvements that you can make. Start with the big stuff and work your way down the list. From the looks of what you've posted, you've got a long list. Then again, don't get disparaged. If you like what you are hearing now, it can only get a LOT better : ) Sean
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FYI, most general use electrical tape is UL Listed and certified to 176 degrees. I SERIOUSLY doubt the claims by those who say it will melt and "make a mess" by being attached to the edge of an amplifier heatsink fin.

Anyway, it worked first-hand for me and several others in my neck of the woods. It's not clear whether those who claimed otherwise have actually tried it or not, so perhaps there have been actual bad experiences. I just don't see how it is possible.

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 ?