Hmn . . .I bought a lovely little T.M.S. SET for my desktop that runs 6N3s and EL84s. Strangely, when I first turned it on the valves all glowed orange at the top and vivid neon blue at the base, causing confusion and consternation for me and my audiophile friend. It sounded superb but the colours were surely wrong and seemed to indicate an imminent melt-down. My pal advised me to switch it off so we could replace all the valves and try again. I found a new set of 6N3s and my pal donated a set of EL84 Mullards (what a guy!) but they made no difference, so we turned it off and let it cool down before removing the base-plate for a closer look. After some fiddling, we discovered a small blue LED wired to each of the valve seats! My pal suggested that maybe the LEDs were used in place of bias adjusters but neither of us had ever seen such a fitting before. Anyway, no matter what valves I fit they all glow orange at the top and electric neon blue at the base. This is, of course, totally artificial, but visually it looks and sounds fantastic, especially when hooked up to my veteran set of Royd Conistons. Who would have thought you could get such amazing sound from only six or seven watts?
Bokway
Red Desert
Central Australia