Audio Research Ref 10

I´ve bought a set of upgraded tubes for my ARC Ref.10 from
2 Winged C (SED) 6550C´s unmatched (they don´t match this tubes anymore) and 10 matched EH 6H30Pi Gold´s
I`m a little concerned about the unmatched 6550´s. I´ve being told by the people of The Tube Store that there is not going to be any problem at all, due to the fact that they will be working in the power supply unit, and not in the audio part of my preamp. Is this ok?
Thanks in advance for your help.
REF-10 ... I've lusted after that preamp ever since I experienced audio nirvana in Randy Cooley's room (Optimal Enchantment) three years ago at the Newport Show.

If I were you, I'd call ARC's tech support and ask them. You'll get the straight skinny from them.
I think they will try to sell me the tubes they carry, that are the same that I want to upgrade...