Solid State to replace Audio Research REF110?

Your problems are not due to having a tube amp but rather to having an Audio Research tube amp. If you do a little reading on the Agon forums, you will find many, many accounts similar to yours---a burst of sparks (if not actual flames) and a burned up resistor perhaps causing damage to the circuit board, all requiring an expensive trip back to the factory. In many of these accounts, this was the second or third time the customer had the problem.

For the life of me, I just don't see why anyone would put up with this. Other designs using the same output tubes are capable of far greater reliability and when an output tube does fail the only damage is a blown fuse that is easily replaced without the amp ever leaving home.

One example of a very good sounding tube amp that should be more reliable is the Emotive Audio Vita, which I happen to own. I have had zero problems during the 3 years I have owned the Vitas, but perhaps more importantly if I should have a catastrophic tube failure it should only pop a fuse, not take out other components. Plus there is no circuit board to be damaged. There are certainly many other good sounding yet reliable tube amps, but I mention the Emotive Vitas because Jonathan Valin of TAS had a pair in his system and said they were very similar in sound to the ARC 610T which was his reference at the time (this was around 2010). He also said the Vitas were the best medium power amps he had heard.

So don't give up on tubes. You just need to try a different brand.

As a former ARC owner, I'd try to find a mint pair of BEL 1001 monoblocks (no longer in production - Mr. Brown deceased).

Also great SS: Ayre, Pass, Krell, Spectral, BAT.

Owned ARC tubes for many years and had only one, non catastrophic, non-tube failure. Arc is great.

I did try a friend's passive pre-amp which caused all 8 6550 tubes to glow a bright blue (scary!).

I wonder how many ARC "failures" were due to using with other-than-ARC pre-amps?

I agree…don't give up on tubes, but go to a different brand that is more reliable and will not blow up on you. I have used Quicksilver amps (no PCBs) since 2006 and have had zero problems with the exception of a bad tube here or there. I had one tube in my Mini-Mites decide to put on a fireworks show, and the amp was absolutely fine, not even a blown fuse. I have also had a JJ arc on me multiple times with M60s, and again, amp was bulletproof.

"I wonder how many ARC "failures" were due to using with other-than-ARC pre-amps?"

Well that seems to makes sense. It does say on the first page of ARC's tube amp owners manuals that: ARC tube amps must be used with ARC preamps or damage will occur. I guess they put it in bold print for a reason.

Might want to check out Octave amps if you stay with tubes. I owned a V70se and traded up to the V110 integrated. I've had several tubes go bad including arc over and the protection circuit works. No damage. They also have a soft start feature to extend tube life.