Demo quad: Sophia Electric Grade A Blue Glass EL34-ST Tubes with 30 days warranty
"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."
Jeff Day's Positive Feedback Online Review: “The Sophia Electric EL34-ST are simply the finest vacuum tubes I've ever had the pleasure to experience in my Leben CS-600 integrated amplifier. They are remarkably musically satisfying, full of emotional impact and excitement, are very refined and articulate, tonally gorgeous, with an effortlessly beautiful and satisfying overall presentation that allowed me to get caught up in the music and forget about everything else.
This patented Sophia Electric coke-bottle EL34-ST (long life version) tube has the richest tonality & the best musicality, a cure for any plain sounding EL34 amplifier.
Sophia Electric EL34 tube is a direct replacement of vintage Telefunken from Germany, or Mullard from UK. It is a premium upgrade choice for amplifiers currently using Chinese EL34, Russian EL34 tubes or Eastern European EL34 tubes.