Amp heat sinks are ringing

All SS amps do this to varying extent. While you can cure / reduce the ringing, doing so will also change the sound of the amp. If you doubt that this could affect the sound, take some vibration readings at the output device using an accelerometer. Those that are "tweaky" have known about this for a LONG time. Nobody has mentioned it as solving this gets to be a pain in the ... You have to find a way to mass load the fins without reducing their natural convection properties. If done properly, you will solve the problem and increase cooling capacity, but it is neither pretty nor simple.

This is why i mentioned building "sound absorbing covers" to go over one's rack in a DIY rack thread. Obviously, some type of ventilation system must be used though. The other alternative is to do what both Dekay and Ernie have done and that is to mount some of your gear in a different room. Sean
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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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If you really want to do this right ( the Goldmund method is "partially there" ), it will require drilling holes or being very creative in using threaded holes that are already in the chassis. These holes are used to anchor the multiple metal damping strips that clamp against the outer edges of the heat sinks. By using multiple clamps ( ala multiple versions of the Goldmund method ) and staggering their spacing, you not only reduce the amplitude of each resonance, but spread the points of resonance out at various intervals. This means that you no longer have one large "ringer" but several smaller, different sized "ringers" of much lower amplitude.

The problem with this approach is that it is not "universal" i.e. what does one do with heat sinks that are staggered in height or depth ? While the manufacturer may have gone to staggered heatsinks to spread out the resonance / reduce the amplitude of the ringing taking place, there really is no easy solution if one wants to try and "damp" such designs.

As several folks noted, using something that is heat sensitive or will melt is NOT a good idea. That is, if you have a good quality amp that is of high bias. You have to remember that some of these amps have their heatsinks running at well over 130* and hitting 150* - 165* at the heatsink in the summer with a room that has no air-conditioning is not uncommon. As such, the smell of cooking wood aka having a "kiln" in your house is not something that i would look forward to. Using soft rubber or some type of material with adhesive is also a no-no as it may melt / produce fumes.

Elizabeth's idea of using the "stoppers" from "chemical beakers" or test tubes may work pretty well as these are designed to be exposed to high heats when "making potions" in the lab as the beakers / test tubes are heated over Bunsen ( sp ??? ) burners. The fact that she's running them on an a Class A amp that does get QUITE hot and has had no problems with them verifies that. As mentioned though, i would be careful with how / where you place them. The further out towards the end of the heatsink that you can get them, the lower the temperature they will be exposed to and the less airflow blocked.

With amps that run cool to the touch, you might not run into many problems using some of the other methods described. Just remember that if you did want to remove your "mod" at a later date, you may have to scrape the goo / gunk that was used to adhere your "damper" from the heatsinks. AS such, use something that is relatively easily reversible or get ready to pull your hair out trying to clean between the heatsinks.

Audiobugged: While one can work on optimizing room acoustics and "draining" the energy from the amp into the stand, the vibration of the heatsinks has to pass through the entire chassis prior to being "drained". There's just no way around the ringing unless you directly address the problem. Sean
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PS... To those "fans" of Goldmund products, i apologize for calling them "Goldman". I must have been fantasizing about Oscar from the Six Million Dollar Man again : )

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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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 ?