I purchased the silver 60 mono’s new 1999 - 2000. Have owned several amps that have come and gone but the QS are the ones that stayed. They are unbelievably reliable. The auto bias works very well but they work and sound better with matched tubes. Mine have blown fuses on one amp but discovered that there were some (1) tube was shorting. After buying a new set of 8 matched it hasn’t blown one fuse. Have tried the kt88, 6550 but prefer the EL34.. I don’t find the bass flabby until the tubes need changing . Because Mike has set the bias low the tubes last a very long time.
I should add that if you have any questions , Mike is very responsive..
I don’t think you can go wrong with QS .. point to point wiring so they can always be upgraded and repaired. Mine have been bullet proof .. when I first heard them I sold my ML amp of 15 years.. ( before Harmon owned) .
the only reason I would sell the 60’s is if I could find a perfect set of the V4’s .
