Valve amp Isolation

[Jimbo]

I have read on a number of occasions that valve amps do benefit from acoustic Isolation. Is this anything to do with microphonic problems with the valves?
Can anyway recommend a good method for Valve amp vibration Isolation or should I treat it like a TT and apply the same methods?:scratch:

[walpurgis]

I'm sure some amps benefit from isolation to decouple them from whatever they are stood upon. Mains transformer generate vibration which may not necessarily be felt through the casework, but will be present at some level (unless the amp has a switching power supply -- nasty and they vibrate too). Damping of casework can be useful and there are remedies for dealing with the microphony of valves (and other components). Amplifier components can generate noise of their own as signals pass through them. Capacitors are known to do this for instance. I use sorbothane pads inder some of my equipment and it seems to work well. Silicone rubber damping rings are available for valves. I'm not convinced about these, as silicone does not posess great damping ability.

[Jimbo]

Hi Geoff,

my valve amps buzz away as the transformers are quite noisy in the casework. Just wondering if this would be detrimental to the performance of the units and contribute noise in the system. I think some sort of Isolation would be beneficial?

[walpurgis]

I've had a few items with noisy transformers. If the transformers are bolted to the chassis, check the the bolts are tight. I've put rubber grommets between the chassis and transformers using the mounting bolts in the past (you may want to earth the transformer body if you do this). If there are bolts holding the transformer together, check they are tight, otherwise they can buzz like mad. Failing that, I've used sorbothane pads between the case or chassis and transformer. This has helped. Did this to my DAC the other day to quieten a buzz. Make sure the transformer still has room to 'breathe' as they can get pretty warm and don't use anything that could melt or catch fire.

[Gazjam]

Clearlight Audio RDC cones work well under my valve amp.
My amps a heavy beast at 30odd kgs, these cones improved things.
Was on a glass surface.

Not too spendy either.

[Ali Tait]

If it's becoming to much of a nuisance, good results can often be had from removing the transformers and sending them away to be re-impregnated with varnish under vacuum.