Mechanical damping of output caps?

Dan K

2013-02-06 11:59 am
Can anyone advise if gluing output caps to the circuit board with electrical grade silicone is a good idea or not. I've seen preople mount these on wood before and use glue, but I've no idea what sounds best. should I just not bother and leave them as is.

This raises the related question of whether a long, thin, heavy cap should be soldered tight to the board, or whether a gap should be allowed for it to flop about.

Sideways shaking tends to lever out the leads if the cap is close to the board. I assume that's why hard glue is used rather than damping material when this is so.

If left floppy, they just need propping up with something stiff enough to keep them in place, but squidgy enough not to act as a lever.

So what's all that silk-filled electrolyte stuff about then? And why has this Sony got a damping pad across it's twin main PS caps, that would serve only to increase the load on the leads, were the caps not glued in place?
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Flat to the board is best, limits any movement, any that are raised from the boar would fail an IPC-610 quality inspection. Most audio gear is not going to experience the vibration levels that you find in equipement used in cars planes, on motor housings, generator sets etc so it shouldn't be a problem. Silicone based adhesion is preffered as it adds some damping, further more the compounds can vary to cater for different vibraion levels and frequemcies, a gen set at 1500 rpm has a different vibration signiture to a jet.
harder gues are often used in lower vibraion units to help keep the devices close to the board during the assembly cycle, even snap fit capacitors can sahke loose before soldering during the movements around an assembly line, and often both may be used.
There is a double sided clear sticky tape that is used in glass store fixtures. They join right angle glass together and is tougher and stickier than the soft foam style types.
You can find it at commercial glass shops
This along with ty-wraps is the best, but not necessary since your not shipping hundreds of product that gets tossed around like a football or like in the movie. " Pet Detective "