Tubes for Audio Research LS-16 Pre Amp

I have been using my pre with the stock tubes that have 3000+ hours on them. I am looking for recommendations as to alternate replacement tubes, and the sonic differences that were noticed in comparrison to the tubes that were originally supplied by AR.

I just replaced my stock LS 16 tubes with NOS tubes and the sonics have never been better. Best upgrade I have made to the unit.
Would NOS tubes also be a good upgrade for an ARC LS-15?
Several months ago, I got some NOS tubes (6H23 6922's)for my LS16 from Upscale Audio. There was a distinct difference when I changed tubes. The sound had more of a euphonic tubier sound which sounded very nice at first. However, I missed the accuracy and detail of the stock Audio Research tubes with the tube rings. So, I went back.

This preamp was designed specifically to be used with the original 6922's which are matched exactly to this preamp. For this reason, the sound of the music seems to lock in with the original tubes. I have to say it is a little drier but it also seems more accurate.

I still change tubes occasionally for a different sound, however, 99% of the time, I stick with the original tubes. So, I would recommend you replace with a matched set from
Audio Research.

I use an LS-16 MK II in my bedroom. It's nice, heck I think the tubes are good for 10,000 hours. It mates well with my VT-100 MK III. All in all I'm pretty happy with the sound. Before that I used an LS-15, I have to admit there was a noticable improvment though for the money the LS-15 is a great piece.

Which NOS tubes did you buy?...where?...cost?...and the big question...what were the improvements that you noticed?