Well I've dipped my toe into the SET waters by purchasing an already completed, approx 5-year old SEX from another member. First let me say that nothing this inexpensive should sound this good. And for reference, I am playing my Quicksilver Minuet Supremes (87.5dB) to comfortable levels in a small, acoustically live room (with sub). Now for my question: the RCA 6DN7 tubes that came with the amp do not appear identical to each other. One tube has a small filament that runs just under the dome of the tube and lights up bright with power. The other tube does not have this filament. I looked at a set of Raytheon tubes and neither of them have this filament. Can someone explain this? Are these tubes OK to use as is?
Thanks.
