High End Audio Repair

Why don't you just contact Pass directly? Mr. Jacoby gave them high marks for customer service. I can see how you would want to have it serviced in NY rather than CA, but having the manufacturer either do/ or coordinate the repair would seem to be the best way of doing this.
Perhaps Pass would agree with you and have you send the preamp to Mr. Jacoby- In that case, he said he would be glad to do it.
Since Select Audio is on your side of the world, why can't you telephone them directly?

Thanks Bob.

I inquired about using HEAR because they're in NY & much closer than CA.
I emailed Select Audio at the same time as HEAR. I've had no reply from Select. 

Okay, so I called them and spoke with Ben Jacoby. His first question was, 'why don't you call Pass directly'?
He made a point that international repair was a PITA(duty and shipping complexities) and would rather not do it unless Pass asked him to.

He also said you could take the Preamp to Select Audio in the UK, who are registered dealers and should be able to effect repairs.
HTH 
Bob

That would be great, thank you. Incoming PM...

Oh, that's good, nothing like an official repairer.  A quick Google shows them to be fairly well rated.
Isn't there a good high end repair shop in the UK or at least Western Europe?
If you want, I could contact them for you. I am sure there must be repairmen/women on your side.

It's a Pass XP-20.

I'm in the UK so have already sent an email but their site states they have a spam filter so if they don't reply within an acceptable time then call. 

They also state they're official repairers of many manufacturers including Pass.

What brand is your preamp? Can't you contact them?
As far as High End Audio Repair, I haven't heard anything about them.
There is a stereo repair center in lower Manhattan that is well respected, but the name eludes me...