Isolation Transformer

i want to try one of these running 2 mono blocks,,right now there just pluged in the wall...who makes a good one
MGE certainly makes one of the best, if not the best.

If the supply in your existing amplifier is well designed then you are not likely to need an isolation transformer feeding it. However, if you are using one of those modern switching amplifiers that seem to be in vogue, or have known power quaity issues then the iso transformer can be invaluable. It also provides a degree of surge protection.

Be advised that, due to the heavy demand that the power amplifier can impose on a power line when charging it's bus capacitors, you will want to oversize the iso transformer by approx. 50% if it's an analog amplfier (class A or AB).
Acme, GE, Square-D.

Shielded is recommended but not essential. If it's going to be in living space, go for Q rated for no hum. For a few more bucks, consider providing balanced power but derate the output by half. Equitech's site has some useful info.
I would try the Topaz isolation transformers. They are reasonably priced and offer good shielding. However I would try using the transformer for the electronics, ie preamp, cd, turntable, as I feel you would get more benefit with the cleaner source for the more sensitive components. For the amps, I would just run dedicated circuits to allow for more current when needed.
If you use a 5 KVA Isolation Transformer in-between your main panel and a sub-panel (like I do) then your amp should benefit from the clean AC on it’s own dedicated line and won’t be choked for power. I’ve tried it both ways and prefer the way my system is currently set up.