new home new power.

...it's already dedicated 220V/20amps line that can probably handle 1000W/ch.

My only suggestion would be to look into changing the 20 amp breaker to a 30 amp breaker. Especially if your speakers like to draw the current from the amplifier.

Ok, let me see if I understand you. It sounds like you have an amp that is currently configured for 120-volt operation.

You have an outlet that is dedicated 220v (20amp?) You want to reconfigure the amp and plug it into the 220volt outlet.

In addition to changing the taps around inside the amp you will most definitely need to change the cord cap (male adaptor) on the amp cord to match the wall receptacle. Is the receptacle twist lock (15a or 20a?) or does it have two horizontal ports on top with a ground port underneath? (Sleepy eyes)

I would not attempt doing anything without talking to the factory and a good electrician first, one mistake and POOF!!!

IMO it would be easier to re-configure the outlet back to 120-volt than re-configure the amp.

Under no circumstances should you ever increase the breaker size. The breaker was sized to protect the branch circuit. Increasing the breaker size without increasing the wire size is in fact a violation of the National Electrical Code

Glen,
Thanks for warnings.
I've degree in electronics and can perform a job of an electrician as well.
Currently my 220V socket doesn't have a locking receptacle but it will have it soon as well as male plug will be replaced accordingly.

20amps for 220V is so good enough that its even more than 30amps for 110V. Do your math and multiply the values to compare the power handled. I believe that even 15A for such circuit is more than enough.

I also spoke with Bea from VTL(I own VTL MB100) and she also said that re-connecting for 220V operation for these amps will be beneficial and more efficient.

I agree and am releaved you know what your doing. You will draw less current half in fact at the higher voltage. It's nice that VTL makes it easy to swap over to the higher taps on their transformer. I see a new trend forming already. It's also pretty cool that you have an exsisting 220v outlet in the area. Don't tell me, you set your gear where the oven use to be. :^)

Take care