Advice on Repairs for Audio Research VT100 Mk II

Many thanks to everyone for the very helpful responses.

As to dealing with local tech shop, I also prefer just trusting the tech guy to give me a fair price, but when we're talking EUR 2,300, I want to understand what I'm paying for and why. I don't think that's quibbling or disrespectful. As to the burden if an issue comes up later, the shop will bear this burden for only 6 months, which is the guarantee they're offering. It's better than nothing, but not exactly confidence inspiring.

I didn't realise that the input tube matching was so complex, as described in  Jea48's post. This was really helpful and makes me think that the price isn't so bad after all. 

I also thought about contacting ARC directly, but that feels a bit like going behind the back of the local authorised repair shop. I would also expect ARC to defer to the opinion of the local shop. But maybe they can give me an opinion on the expected cost/benefit going forward if I go ahead with the repair, as petg60 pointed out. 

And yes, this amp already feels like a liability. I love the sound but the amp has needed two repairs within the first 6 months, so it's really put me off the whole tube amp thing. The first repair was replacing two fan resistors, which I did myself and was actually kind of fun, but I didn't enjoy it enough to say, yeah, I'm going to invest the time and energy to learn DIY tube amp repair and replace 20 resistors. Thus, my idea was to get the amp repaired, sell it, and go back to transistors. But if I go ahead with the repairs, I will have invested EUR 4,700 and I'm sure I wouldn't get that much on the second hand market. So either I accept the loss and move on or I use the amp for (hopefully) a few years before the next repairs are needed. If I knew I could get 4 years out of it without another repair, I would choose this option.

Did you or the guy you bought this amp from install new 6922 tubes in the Amp?

Or maybe did the guy you bought the amp from pull all the tubes from the amp for shipping? If yes each tube would have to have been marked for each tube socket they were removed from and reinstalled in the same tube sockets they were removed from...

Thanks again to everyone who responded. The tubes were already installed when I bought it and I had a car share and a short drive, so I didn't bother removing the tubes for the drive home. I think he said that the tubes were fairly new. It was my first tube amp, so I didn't know which questions to ask. The former owner is actually really helpful and offered to help pay for the repair if I get the work done at the tech shop here in Berlin that he regularly uses. I however wanted to get it done at the authorised dealer in Hamburg, which he considers to be overpriced.

Some responses above have suggested eating the costs and moving on, but that would mean selling the amp as defective and I wouldn't expect to get more than EUR 500 for a defective amp. That would mean a loss for me of EUR 2,000. Or do you think I could get maybe EUR 1,000?

So, at this point I think I will either bite the bullet and get it repaired at the ARC authorised dealer or have it sent back from Hamburg (which is another EUR 100) and get it fixed by the tech guy here in Berlin recommended by the former owner. I just don't feel like lugging this beast around any more. I don't have a car, so moving it always entails doing a car sharing or taxi/Uber.

I also sent an email to ARC as suggested by some of the posters, so we'll see how they respond. 

Since you mention that it is your first tube amp I want to mention that hopefully you are aware that you should not turn a tube amp on and off and back on quickly without giving the capacitors a couple minutes to discharge.  That can lead to problems such as you describe.

I think I did do that a couple times because I was following another rule that someone told me: always turn on the source (DAC/pre-amp) before turning on the amp. Once or twice I forgot about this and turned on the amp first, so then I turned it off, turned on the DAC/pre-amp, and then turned the amp back on. Doh.