I generally don't care for EL84 amps, but had a feeling this one would be different. Heard some great clips. Found one barely used at a great price locally, so figured why not. Plugged in, I could hear the promise of the amp. Something about the size of the sound, the depth. Big volume for a 15 watt amp. Kinda light on bass, which I chalked up to the EL84s. The NFB switch is an inspired touch, but it's all or nothing. So I took it to my tech buddy to have a analog knob installed. In the meantime, I'd lined up some NOS tubes. Vintage telefunken and RCA smoked glass ES84. Started with the preamp tubes. In some amps, that's where the biggest tone difference lies. Not this one. Tried several old 12ax7s I had lying around. A definite improvement can be heard. It's a subtle, but noticeable difference. A little warmer, a little smoother. Next up, the telefunken EL84s, Here the change is not subtle. What had been a promising, large sound, became something much sweeter, more complex. The sound filled in. No longer light in the bass. The p90s I mostly play now livened up. With enough volume and just a little clean boost, notes just hang around, sustain with a hint of feedback. Really pretty sounds. To the point I'm not even trying the RCA tubes. Sounds too good to mess with. And this little NFB mod is quite useful. Turn a quarter, or halfway up, volume starts to increase, and the sound thickens. It has a somewhat similar effect as you might hear from a really tasteful overdrive. In my case, a Greer Lightspeed. I can dial in something like that drive sound just with the NFB knob. Anyway, this Varsity is so fine. No idea how it would do with humbuckers, as I have none now. With single coils, it's something special.