The Svetlana 6L6GC vacuum tube has a nice balanced sound that is not as bottom heavy as say the TAD and not as bright as the SED. The midrange response is very nice. No honk and no really pronounced EQ shelving as you manipulate the tone controls of the amp. Very smooth and balanced frequency response that sounds great driving Celestion speakers which tend to be a bit honky in the mids and extreme in the Bass and Treble. Clean sounds are pretty chimey and overdrive is thick with lots of sustain. I tried a Fuzz Face, Vox Fuzz, Linear Power Booster, reverb and delay. Effects sound great and don’t make the tube mush out. Microphonics and hum simply aren’t factors with the SV6L6GC tube since they use a very good system for mounting the internals. They give off a good bit of heat and this is facilitated by oversized wings on the plate structure. One of the best applications for these tubes would be in Marshall JTM 45 and Bluesbreaker reissues. These amps usually ship with the Sovtek 5881 WXT+ and sound pretty dead. I have a meticulously built JTM45 head and these tubes sound better than Siemens EL34’s or Shuguang KT66’s. I wouldn’t believe it if I hadn’t done it to my own amp. I’m running the tubes at 40 mA and 466 plate volts. I ran them up to 48 mA without problem.