Albert,
amps can get a bit soft sounding and lose a bit of life with some passive decoupling. and it's hard to predict. you need to try it and listen. the reason is that most good amps are voiced to be on floors near speakers so they have their own internal damping. adding passive decoupling can then potentially be in conflict with the designed in damping.
my dart amps have suspended circuit boards inside for decoupling. you have to remove the shipping bolts to allow the boards to hang free once installed. so when I tried decoupling under them it got muddy sounding. it was better without.
if your floor is post and beam I'd first brace underneath it to make sure the floor is completely solid underneath the amp. that will yield the biggest gain in performance. if the floor is moving and you add the mass of a Vibraplane it will just change the frequency of the resonance.
maybe a good place to start is ask your amp manufacturer what approach they recommend.
amps can get a bit soft sounding and lose a bit of life with some passive decoupling. and it's hard to predict. you need to try it and listen. the reason is that most good amps are voiced to be on floors near speakers so they have their own internal damping. adding passive decoupling can then potentially be in conflict with the designed in damping.
my dart amps have suspended circuit boards inside for decoupling. you have to remove the shipping bolts to allow the boards to hang free once installed. so when I tried decoupling under them it got muddy sounding. it was better without.
if your floor is post and beam I'd first brace underneath it to make sure the floor is completely solid underneath the amp. that will yield the biggest gain in performance. if the floor is moving and you add the mass of a Vibraplane it will just change the frequency of the resonance.
maybe a good place to start is ask your amp manufacturer what approach they recommend.