FB, I only have the NOS GE KT66s at the moment and as I mentioned I really like them. I cannot help with your dilemma. Any thoughts on Groove tubes? I am tempted to go that way for a listen.

Thanks Bear,

Groove Tubes are specially selected and usually go in guitar amps. There have been some that are now extinct that were great for audio. I'm not familiar with the current offerings.

I may get the Tung Sol big bottles soon but I'm enjoying 6V6's.

I use the Tung Sol Big Bottle 6L6G's in my Mcintosh MC30's. It is a VERY good tube. It is actually an uprated 6L6GC in the G bottle. Get em from Jim McShane. He is pretty thorough in his testing/matching.

Ended up getting a KT88SET from Dennis. The 45 will be a bit further down the line. I need to clear out some gear and make room first.

Yeah, those TS big bottles are almost universally praised. I wanted to try the Treasure KT66's but am going to wait until the 'what's happening' with Shuguang and Psvane air clears.

I really like 45's but, IMHO, you must have the right speakers, like horns or HE single drivers, for them to really sing. I had a Korneff 45 amp and 76 preamp and kinda regret selling them.

I had an interesting afternoon Saturday. I brought my amp and preamp
to a friend’s house that has modified Klipsch La Scala's 104db. The Inspire gear was dead silent. Started out with Penta Labs KT88's, nice. Moved on to Sylvania 6L6G's. Very nice but I liked them better with my Heresy III's. Up next were the Pope 6V6GT's. Here is where it gets interesting. I forgot to change the rectifier and ran them with a 5Z3/5U4G instead of a 5Y3/80. Without fanfare this combo was absolutely wonderful. Huge soundstage..blah blah blah, etc. My buddy was floored, so was I. We then used the LP27a with his 45 and 2A3 SET amps. I preferred the Tom McNally 2A3. The 45 was a Korneff clone that had not been run for a year so it may have needed some more time to get settled in. The Pope/5Z3 combo was not in the least embarrassed. It was that good.

I just ordered a pair of new production TS 6V6GT's and will try them with a 5Z3 and 274B. I am not suggesting anyone else try this because my amp has 20 watt transformers and can apparently handle the demand.

I'm sure you will really like your new amp!

I did a little homework and concluded that the rectifier has a large effect in these amps. The VDC on the power tube plates and voltage drop is the key. Lower voltage drop and higher VDC increases power and dynamics for a given output tube. Just don't exceed the VDC of the power tube used. That could happen with 6L6G's and 6V6G's, usually they are the ST or coke bottle shaped tubes. The new Tung Sol is really a 6L6GC and can handle higher plate voltages. The Pope 6V6GT can also.

From Dennis when I asked about tube combos in my amp:

"You may use any of the popular beam power output tubes in your Inspire music machine. When using the vintage 6V6 ST coke bottle tubes please use a 5Y3 rectifier tube. Other than that have at it. KT150's sound nice as well."

This applies to my KT88 SET that he built to my spec. The xfrmrs can handle a very wide range of tubes.

Thanks, good to know and straight from the builder. My amp has 20 watt transformers and can handle a wide range of tubes too. He told me 5Z3's and 80's initially so I was being cautious. My amp has a UX-4 rectifier socket. I have an adapter for other rectifiers.

I have some TS 6V6 reissues coming. Very good tube. Sounds much better than the run of the mill old stock. I had a pair but send them to a friend in Panama.

I made a table of parameters for various rectifiers, voltage drop etc. and have to shrink it a bit to get it to fit in a post. I'll do it soon.

All the rectifier info you need can be found here:
http://www.fourwater.com/files/fullrect.txt

Yes, that is very good.

An inquiry to Dennis elicited this response:

"Absolutely, you may use the 6AR6 with an adapter as the output tube. I just recently started running 6AR6's and also the special 6384 edition. I believe you will enjoy the presentation. Use the KT66 position on the tube selector front panel switch. Also if you go for the 6384 tubes you may wish to try the KT88 position. Let your ears be the judge."

So you were correct. Interesting about the 6384 comment. I sometimes get the idea anything goes with these amps with a few exceptions. Amazing product these 'Inspire'. I wish I understood it all better. By the way Twanny, the article on rectifiers is most interesting though mostly beyond my feeble brain.