I have been using various EL34's in our Rachel amp since we received it just decided to order two types of KT77's just to experiment. I have a set of JJ's and Gold Lion's coming in the next day or so. I know I will not be experiencing the CCE or Hazen Grid Mod with the 77's but it seemed like the logical choice to start rolling output tubes. Anyone play with these in their Rachel? Happy listening, Chris.

Interested to see what they do for you.
I just ordered some EL34 Wing =C= SED Cryo Matched Pair from Cryoset.
Hope money was well spent, there not cheap.
I have maybe 40 hours on the Rachael now coming along well.
New interconnects coming soon from My audio cables (MAC aka RAC) also to replace the super cheap stuff I have now, once again, hope money well spent.

I own and have used the following output tubes in my Rachel being driven by my Decware Preamp from a Conrad Johnson HD3 DAC from Apple I Mac from VOX an Spotify sources, all into Klipsch Heresy III speakers:

EL34:

Tung Sol
Mullard Reissue
SED Winged-C
Sophia Electric
Shuguang Black Treasure

KT77

Gold Lion

KT88

Gold Lion

They all sound noticeably different.  The best sounding are the Sophia Electric EL34, SED Winged C, Shuguang Black Treasure, Gold Lion KT77 and Gold Lion KT88.   If I had to pick one favorite, it is the Sophia Electric EL34 (a coke bottle shape fat tube).  The SED Winged C, no longer in production, are just about as good.  A little more swirl but not as complete as the Sophia Electrics. As many reviews report, the Gold Lion KT77 kicks ass: I can understand why some prefer it to all others. The Shuguang Black Treasures are almost as expensive as the Sophia Electrics and are quite smooth but less expressive as the Sophia Electrics and SED Winged-C, both of which are noticeably bouncy and rhythmic, to wonderful effect.  The Gold Lion KT88 are the most full range, except for the Sophia Electric, which do everything about as well but sound more beautiful.  The Gold Lion KT88 don't sound thin, certainly not after broken in.  They are noticeably fuller in range than most others (although the KT77 sound even stronger in the Rachel--they're what you'd want for rock-n-roll, just a little harder sounding that true EL34s).  

If I had to factor money/cost into it, I'd say the Winged-C are best/most musical.  They're really wonderful.  But the Sophia Electric are even better in many of the same ways.  Just more of that magic.  

I'm waiting now on a pair of PSVANE Black Bottle KT88 and that ought to just about round out my sampling of non NOS tubes (although the Winged C are now considered NOS, since the factory isn't producing).  

It's wonderful fun.  I change tubes every week or so, depending on what I think I'll be listening to the most.  I keep my tubes in an expensive antique leather attache case, with gold plate clasps.  It's a cool feeling opening that thing up to peruse my samples and settle on a choice.  The change in sound is subtle but distinct and I can take the sound in a lot of different directions.

The biggest change to my Rachel's sound, however, is on account of the preamp, not the tubes.  I've mono amped the Rachel into a high efficiency (99 db per meter ! watt) Klipch Heresy and it didn't make nearly as much difference as adding the preamp, which gave the amp input/output MUCH more body and macro/micro dynamics.  The tubes fine-tuned what the preamp delivered in spades.

I have two other better/more expensive systems in larger rooms in the house: Conrad Johnson systems with higher-res DACSs.  But the nearer-field listening in my bedroom with the Decware SET setup is more hypnotic, though obviously not truly as high-fi as the Conrad Johnson setups (their soundstage and finesse are way beyond the Rachel).  I just don't have enough money right now to know whether the better/bigger Decware amps would be even better.  Conrad Johnson's best preamps and amps are pretty far out there, but expensive as heck, too.

With the preamp and Rachel and Conrad Johnson DAC and all those wonderful tubes, I'm a very happy, 3 hour a night listener.

Enjoy!

I'm sure you'll enjoy them.  If you get their best ones, which may or may not be necessary but is what I did, hence all I can vouch for, you'll be happy.  I have a feeling they're the best non-NOS we can get for that amp, especially the newer ones with the Hazen-Grid modification (which Steve says operate only with true EL34s).