HK suggested:

try a good 6SN7 smoked glass RCA with adapter in the front position. The added soundstage dimensionality is pretty nice

I recently did some tube rolling that seems to have bumped my UFO25 into a higher level of performance with noticeable improvement in the sound stage. It was recommended that I place a CryoTone 12AU7, which I had in the ZRock, in the input position of the amp. The past couple of evenings have been remarkable as a result.

I forgot, however, that at about the same time, I had returned a 6SN7 smoked glass RCA to the front position of the CSP 2+.  

I will need to investigate if one or the other tube switch resulted in the positive change, or perhaps there is something about how the two work together that results in such a positive gain. The bottom line, however, is that the change is remarkable.  

 

Lon and Roger,

Thanks for the info on the 6SN7 tube.  I actually have a Decware 6SN7 that I bought a while ago from a forum member.   I do plan to give it a try… need to buy an adapter and then give it a whirl.  

Thanks,
Dom

Mistake and typo in my last post #253. I have a Decware 6N5P Decware tube and not a 6SN7.  

Needless to say I started digging for some RCA smoked glass 6SN7 tubes  My adapter will be here the second week of July, so I have some time.  Went on Brent Jesse’s website for more info.

Question…out of the smoked glass RCA’s, does anyone have a preference on the short or medium tubes besides Kamran who already posted his favorite.  So far I’ve been eyeing up the 6SN7 GT’s.  

Dom

That last link to SSNR for RCA 6SNR smoked glass did not seem to work.  Try this one instead:

https://www.surplussales.com/Tubes-Sock-Acc/6/TubesListed_6-5.html

All this talk of RCA Gray Glass 6SN7 led me to move a pair of mine from the CSP3 to my SE84UFO3 Monoblocks.

Which led me to roll rectifiers and the 12AU7 in my ZROCK2. The new DAC I have keeps seasoning in and impressing me and is leading me to choose different tubes in my complements to take advantage of its clear and smooth nature.

So with the 6SN7 and adaptor bases in the input of the Monoblocks I settled on a pair of RCA 5V4G as rectifiers (and I have RCA 0D3 in for the output tubes, and 75C1 as regluation tubes for the input tubes, and Steve's output tubes in the Monoblocks). That led me to a lot of experimentation with tubes in the ZROCK2 and I settled on an RCA 6189. I'm still running Amperex 6085 with adaptor bases in the ZTPRE--that's an amazing tube set I just can't seem to do without.

The combination of all these is an amazing tonal balance with some startling 3d details and a great dynamic sense to the presentation.I'm enjoying amazing sound with all types of recordings, which is my main goal.

So I expect my SEWE300B to ship soon and upset the apple cart with its new style and character. It's a shame that we're about to have the hottest temps of the year yet for a few weeks--my main system is in the hottest part of the house. If I run the air I can't listen, the unit is so loud. So I'll begin what I do this time of year: run the unit a while, shut it off, listen as long as I can before getting too uncomfortable (Fiona the dachshund is the first to not want to take it any longer) and then repeat for the next session. Is it autumn yet?

Whew, we're sort of in the same boat. I love winter the most. . .the system sounds best then for some reason. And I feel less guilty at whiling away the hours just listening to music.