I have owned a pair of 1610's since they first came out - about 18 or 19 years. They are built like tanks. Normal maintenance has been done - replaced electrolytic caps in the power supply a couple years ago. While it was back for service, I had the BNCs on the back switched to RCA (to eliminate an adaptor), had the rectifier upgraded to hexfreds, replaced the coupling caps with Teflon caps. I have also had custom power connectors made to route the AC from the lower deck to the upper deck. Also replaced the stock cable for signal from 300B to 1610 stage with a custom cable. I ran it with single ended RCAs from the Aesthetix Io for years, but at one point switched to balanced cables from the Io. Even thought it is single-ended topology, it sounded "better" (to me).
Overall, this amp has a beguiling presence range. Singers are just there in the room, instrumentalists sound like they are there playing their instruments. All the desirable audiophile attributes in spades - soundstage, air, high and low extension.
It does take speaker and room synergy to get the best performance. My Von Schweikert speakers have self-powered subs, so that relieves the amp of having to drive deep bass.
For my tastes - which is mostly classical and jazz - it is obviously a keeper. Replacement 1610 tubes have been problematic to source. Over the years, I have purchased a couple spare sets to set aside when I could find a reliable tube dealer to source them.
The KR 1610 tube was designed for this amp. It is a perfect match.
It does take the right speaker to pair with the amp.
