40th Anniversary Pre Amp and Repair History

I’d like to hear from anyone that’s using the Audio Research 40th Anniversary Pre Amp or anyone that has owned that unit in the past.  Did you experience any repairs with your unit?  I’ve had mine repaired twice in the last year.  It’s a bit frustrating.  Yeah, the unit is 9 years old but still it’s a quality, high cost piece that should last 20 or thirty years no problem.  Have you owned or do you own this piece?  Any problems with repairs?