I've been running the Sophia Electric EL34-ST vacuum tubes in my Leben CS-600 integrated amplifier ever since I reviewed them for Positive Feedback back in August of 2017, and I've put a ton of hours on them since then.

In my "Summary and Conclusions" for them, I said:

"I'm noticing a pattern here with both the Sophia Electric Aqua 274B rectifiers and the Sophia Electric EL34-ST power tubes, they just obliterated every contender in my experience, it wasn't even close."

"The Sophia Electric Aqua 274B rectifiers and the Sophia Electric EL34-ST power tubes (above) were leaps and bounds better musically and sonically than anything I have experienced in my McIntosh MC30 monaural amplifiers, or my Leben CS-600 integrated amplifier, respectively."

"I don't know if it's the ST bottle shape, or the noise reducing blue glass, the design & materials of their internal structure, or Richard's prowess in voicing tubes, but the Sophia Electric Aqua 274B rectifiers and the Sophia Electric EL34-ST power tubes are both home runs by Richard, and they are simply superb both musically and sonically."

So now it's over 2 years later, so I guess you could consider this a long term report on the Sophia Electric EL34-ST's ($100 each), as well as a quick comparison with a quad of SED "Winged C" EL34 tubes from my tube stash (about $60 each these days), which are also very highly regarded EL34 tubes.

I listened to my CS-600 in my vintage Altec Corona 832A loudspeakers (below) based bedroom system, streaming Jazz24 from my iMac to my Mhdt USB DAC.

The Sophia Electric EL34-ST's took quite a while to run-in, but once they were run in they sounded as beautiful as they looked with their blue ST shaped bottles.

The Sophias have a purity of tone that is quite incredible, they are smooth and sensual sounding, and with a colorful and beguiling presentation of the music.

Since I haven't listened to anything else but the Sophia Electric EL34-ST's in my Leben CS-600 integrated for a couple of years, I thought a comparison to my SED "Winged C" EL34 tube stash (above) would make for a good check on my long term impressions of the Sophia's.

Previously I had used my SED "Winged C" EL34's for quite a while, so they are well run-in.

Well, no offense to fans of the NOS SED "Winged C" EL34 tubes intended, but in comparison to the Sophia Electric EL34-ST's, the SED's sounded coarse, rather two-dimensional, somewhat forward and brash, and not all that musical.

Honestly, I couldn't wait to get the SED "Winged C" EL34's out of the Leben CS-600 and get the Sophia Electric EL34-ST's back in to restore the musicality of my system. 

Well, the Sophia Electric EL34-ST vacuum tubes ($100 USD each) absolutely creamed the SED "Winged C" EL34 tubes ($60 USD each). 

The Sophia Electric EL34-ST vacuum tubes are expensive at $100 USD each, but they definitely deliver from a musical & sonic perspective, and are in a different league from SED "Winged C" EL34 tubes.

The Sophia Electric EL34-ST vacuum tubes seem to be going strong after two years and about 6 months of playing time, averaging probably about 4 hours a day of use. If anything they sound better than ever, so I'm hoping they'll keep going for another year or so before they need replacing.

At around $400 for a quad Sophia Electric EL34-ST vacuum tubes that works out to be $14.30 USD a month to date (28 months), and if they make it to 36 months it works out to about $11.11 a month. That's a little less a month than the price of a Netflix subscription.

It was a no contest situation, the Sophia Electric EL34-ST vacuum tubes are by far my favorite EL34 tubes. Some things you appreciate more over time, and the Sophia Electric EL34-ST vacuum tubes have stood the test of time.

As always, thanks for stopping by, and may the tone be with you!