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.

Dump it. Buy a ss amp. Not worth the 2k repair charge. 
call it a learning lesson. 

ARC amps are built well and tend to be reliable. Until they're not. I believe most ARC experts and fans will admit that there were some clunkers along the way, in terms of sound, design and reliability. I had a VS110 (which was the lower-tier amp contemporary of the VT110 IIRC) that was remarkably reliable for ten years of constant usage. 

Most-but not all-tube amps are expensive to maintain. My ARC Ref 150SE uses eight KT150's. That means paying $1600 or more every three years more or less to re-tube just the power tubes, closer to $2800 if you opt to buy ARC's "specially screened and matched" tubes. 

I don't know this particular model, but had ARC gear for decades- multiple amps, preamps. I still have the Dual 75a that I bought new in 1975-- it is sitting idle with a fresh tube set I bought from ARC a number of years ago. They were never cheap to maintain but I did get a lot of utility out of them. One question I would ask given the price is what kind of warranty you can expect after having paid to replace all the tubes and associated resistors? I used to deal w/ ARC in Minn. and they stood behind their work. That was quite a few years ago- I don't know what difference it makes that you are dealing w/ an authorized facility in another country or how things may have changed given that the company is in different hands and the amp is relatively old from what I gather. Typically, warranties on tubes themselves are limited, but....

I still run tubes, and periodically have the manufacturer go over the amps, line stage, phono stage, etc. There is a running cost to these things-- I like the DR variant of the 6h30 which, for a vintage quad (used in my line stage) is not only costly but very hard to find these days. Generally, I've found tube gear of this calibre to be pretty reliable other than routine maintenance, tube replacement but cannot speak to whether this particular model is worth investing in for the long run. If it is, bite the bullet, get it done and enjoy it! 

@edward78

The VT100 MK II first came out in 1998 though 2000, (maybe through the spring of 2001). The amp is at least 21 years old. I am surprised the Tech that gave you the price for the repairs didn’t mention that. How about the electrolytic caps in the power supply? They are probably original. They may still be ok and last for many more years. But... I would suggest you call the Tech and ask him what it would cost to replace the caps.

https://www.arcdb.ws/model/VT100

If it were me, I would lick my wounds and move on and caulk it up to experience learned... You will end with a whole lot more money in the amp than it is worth.

FWIW, there is a very good chance the guy you bought the amp from knew the amp was ready for a complete re tube.

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