Sophia (blue) EL-34-ST Tubes

Cellcbern

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My Unison S6 is a parallel, single ended, Class A integrated amp that was Stereophile "Class A" and received multiple 5* reviews online. It sounded good with the Tung Sol EL-34B power tubes (3 per side) that came with it, but was not a match for my modified Pathos TT RR. With the new Sophia Electric blue EL-34-ST tubes the S6 is a revelation, matching the TT RR's timbral accuracy and surpassing it in articulation, bass heft, and three-dimensional imaging. If I were to put a % on it I would estimate that the S6 is 60%-70% better/more musical with the Sophia tubes versus the Tung Sols.

Note that I am using Mullard, Amperex, or Sylvania (black) long plate 12AX7's in both amps.

Jeff Day reviewed these new Sophia tubes for Positive Feedback, and also on his "Jeff's Place" blog.
 

DaveC

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Thanks, these look very interesting... I'm currently using new Gold Lion KT77, have you tried these?
 

DaveC

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Well after reading about them and your report I'll have to try a pair. Thanks for the help spending my money! ;)

I hope these last!
 
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Cellcbern

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No wish to further lighten your wallet, but my Sophia blue 274B arrived today. Unlike other 274B's it is designed to be a direct drop-in replacement for a 5U4G. I am using it in my Modwright PS 9.0 power supply. If you like
the sound of the blue Sophia EL-34's and have a component that takes a 5UG4 rectifier, you will want to try this special 274B. Right out of the box it produced the most natural piano tone I have ever gotten from my system.
 

DaveC

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My power tubes are running an Amperex 5AR4 rectifier and driver is SS rectified. It's running the Soviet metal-base version of the 6SL7 and 6SN7. I think Sophia does offer a 6SN7 version, maybe I'll try them one day... :)
 

DaveC

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I got my tubes already! Put them in this morning and just starting to burn them in, one was a touch noisy at first but has now settled down. At first a little closed-in but currently opening up and I can hear the potential. They should have named them 300BL-34s, they do seem to have some of the qualities I've heard in 300B SETs. A touch dark vs the GL KT77, smooth, fleshed-out and realistic sounding midrange with a little "bloom". So far a tonally different alternative to any EL-34 I've tried. They still have a ways to go I'm sure, so I will report back later.
 

Cellcbern

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The Sophia 6SN7's are TJ Full Music tubes labeled for Sophia (unlike the blue EL-34's and 274B which Richard Wu of Sophia designed and has made in China). I used them for years in my Modwright Sony 5400es based on Dan Wright's recommendation, and preferred them to the NOS RCA and Sylvania tubes I tried. However the Psvane CV-181T-Mk. II are the best sounding 6SN7 equivalents I've heard in the 5400.
 

DaveC

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Good info on the 6SN7s, best I've tried are the Soviet metal-base tubes like in the link below. Some say the hole-plate tubes labeled 1578 are the best, others the regular black plates. Price should be $50/pair used/good or $80ish new. Some try to call them all 1578 and charge $200/pair. There is a 6SL7 version as well. 6H9C maybe... I use those as well, they were cheap and also really well built. I have some high end 6SL7 these are just as good as, imo.

https://www.ebay.com/itm/2x-matched...epid=0&hash=item1c9ec0210a:g:-TIAAOSwmSdaYftg

At this point I'd say the Sophia EL-34s are better vs any of the others I have here, which include old Mullard, XF4 maybe?, RFT, Winged-C, old Tesla, and new GL KT77. Of these the new GL are my preference, but all are nice, The Sophias have a richer midrange, timbre sounds more realistic and maybe images are a bit more solid, I think my soundstage was excellent before but now with the Sophias there is more solidity to the images, more density of tone... this goes along with the richer midrange I think.

I was a little worried they wouldn't really open up and become as fast and clear as the KT77, but I think they are getting there, there has been a big improvement in this area from brand new. I would still say they are more 300B-like.
 
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Cellcbern

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Mine have about 70 hours on them and are steadily improving.

Thanks for the 1578 recommendation. I ordered a pair on ebay to try.
 

DaveC

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Wondering if anyone has compared these to the true NOS like XF2's or Sylvania Fat Bottle?

I listed the tubes I have 2 posts back, which include some NOS varieties. The old Teslas (pre-JJ) are probably the closest to the Sophias, but the Sophias really have a different character vs any other EL34 type I've tried.

I'm switching back to the GL KT77 today, should be interesting... I've been thinking the Sophias are maybe a bit too much as far as midrange bloom/warmth for my system, we will see! :)
 
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Cellcbern

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After more extensive listening I have also found the blue Sophia EL-34 tubes to be a little too much of a good thing. In my Unison S6 they are bright on a significant number of recordings. For example, listening to the Ray Brown Trio's "Summer Wind - Live at the Loa" SACD, when Gene Harris gets into the upper octaves on the piano the notes start to sound metallic. I switched to a matched sextet of the Gold Lion KT-77's and they were similarly bright. I suspect that this result is unique to the Union S6 with its unusual parallel single ended ultra-linear circuit. Since the amp was voiced for EL-34's I ordered a matched sextet of the Psvane EL-34 PH tubes which are updated replicas of the legendary metal base Phillips EL-34's. These did the trick - all of the positives of the blue Sophia's without the brightness. In the Unison S6 these are the best power tubes I've heard.
 

Ron Resnick

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Any more Sophia EL34-ST direct comparisons to NOS Mullards?
 

Designsfx

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I’ve read many a praise on the Sophia- the only direct reference to Mullard was “definitely better then used NOS Mullard xf1 or Genalex KT77” but I’m not sure of what equipment that person was using them with. Seems the issue now is they’re vapor ware. I’ve been trying to find a quad for my Lampizator for two months now with no results. I got a response from Sophia telling me there was a pair (not sure if that means “one pair”) available but no quads. I haven’t heard back as to a date when/if they will have these available for sale.
 

DaveC

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I'm still using GL KT77. IMO they're better than many vintage tubes but price is much higher since they're made in Russia, at this time I wouldn't buy more. I had/have 8 of them and my SET uses 2, so I'll have them for a while. I've got quite a few EL34 types, inc NOS Mullard XF2, Siemens, JJ, and more. I'd have to check, haven't looked though my EL34 stash for a while.

The Sophia tubes are nice if you like the warmth/tone they add, but they aren't the most neutral choice.
 
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Ron Resnick

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At this point I'd say the Sophia EL-34s are better vs any of the others I have here, which include old Mullard, XF4 maybe?, RFT, Winged-C, old Tesla, and new GL KT77. Of these the new GL are my preference, but all are nice, The Sophias have a richer midrange, timbre sounds more realistic and maybe images are a bit more solid, I think my soundstage was excellent before but now with the Sophias there is more solidity to the images, more density of tone... this goes along with the richer midrange I think.
Hello Dave!

If you happen to remember your impressions would you please elaborate on the sonic differences you heard between Sophia EL34-ST and Siemens RFT EL34?

Thank you.
 

DaveC

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Hello Dave!

If you happen to remember your impressions would you please elaborate on the sonic differences you heard between Sophia EL34-ST and Siemens RFT EL34?

Thank you.

Sure, the Siemens is pretty neutral in character, so less warmth than the Sophia. The Sophia's tone is more like a 300B, warmer than typical for an EL34. Siemens is pretty resolving, clear and overall would be my preference between the two. I've been using the GL KT77s, I got 8 of them a few years ago and have been using them since then without trying anything else, and it's been quite a while since I tried Siemens EL34s.
 

Ron Resnick

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Sure, the Siemens is pretty neutral in character, so less warmth than the Sophia. The Sophia's tone is more like a 300B, warmer than typical for an EL34. Siemens is pretty resolving, clear and overall would be my preference between the two. I've been using the GL KT77s, I got 8 of them a few years ago and have been using them since then without trying anything else, and it's been quite a while since I tried Siemens EL34s.
Thank you!

do you know how either of these compare with a Shuguang black treasure?
 

DaveC

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