Amp heat sinks are ringing

I don't know if I'm in the ballpark on this one, but I had a resonance problem with the motor on my hot-water tank system. I found these magnets at a surplus store about the size of a domino that I strategically placed on the offending ringing area and it changed the frequency enough so it is no longer a problem.

This is the first I've heard of this problem with the CAM-200s-- I'll have to go home tonight and see if mine do it, although where they are located I would never hear the heatsinks ringing, but I should hear their effect on the sound coming out of my speakers.

As for putting something over or under the heatsinks I think they get too hot to make that an option.

I would think that it would be a fairly simple matter of "wedging" a piece of appropriately size rubber (maybe a 1/4" long piece of the appropriate diameter automotive heater hose?) in between fins at their midpoint-- you'd not really adversely affect airflow or cooling area, and you should greatly reduce or eliminate ringing since you've just effectively halved the unsupported length of the fin-- this would have to alter its resonant frequency substantially.

Maybe 2 rows, one 1/3 of the way down, one 1/3 of the way up, of small pieces of appropriately size rubber (or cork) material would be more effective.

What effect this would have on the amp's sound is debatable, I guess-- although I can't see how eliminating a resonance there that's being excited by room sound would be anything but a positive for sound quality.

Goldmund understands and addresses this problem..

http://www.goldmund.com/old/Millennium/mechanics.html

Unfortunately, finding someone to make a heat sink clamp out of brass or aluminum ain't gonna be cheap 'n easy.

Pm: It's not a matter of whether the change is good or bad, but that it DOES change. As such, the sound that you are used to and may have worked hard to achieve can be altered for better or worse.

Gs: Thanks for the link to Goldman's solution for this problem. Like i said, it ain't pretty or simple : ) Sean
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There are a couple of alternatives that I have used succesfully:
1- Use small strips of bycicle inner tube less than 1/2 in wide rolled up to adequate thickness and push them between adjacent fins down to close to the fin base (shoot for this dimension when you roll the strips not the outside gap between fins). If you choose to do this in the lower part of thew vertical fin they'll be hardly noticed with several advantages, it´s a reversible tweak, tube is black as the fins are if needed can be done at middle height, add more etc. The effect on convection is minimal and you can kill the vibes.....
2- Use a small wire or better a small aluminum piece and adhere it to the fins with a hot melt adhesive gun in the underneath the lower portion of fins.
3- You can also bridge the fins with the holt melt adhesive and decrease the ringing acordingly.

Some options are far more effective than others and easier to implement depending on how careful you are the other too can be used but there's more potential problems So weight the options and the compromises you might get into.
I prefer the first one since it´s easy and totally reversible.
Have fun and kill the ringing.