Audio Research I/50

600 hours is talking about the amplifier break in and it is the one time event.

do you sure that after changing to a new tubes there is no an additional break in?

I am sure there IS tube break in, but it is not 600 hours.

bump

A local dealer let me take one home for a few days.  I thought it was great, especially for the price.  I wanted to order one but there's a 2 month+ wait and I have a Leben on order that I have a 5 month wait for.  I was using the ARC as a temporary amp while the Leben was being made. I still may get one once the DAC module comes out in June. They are not auto-bias. You need to flip it over and do it manually as someone already said. That's according to the dealer.