On 10/16/23 01:51, Tony Miklos via Jukebox-list wrote:
Yes, they were running hot as hell! It's because the metal absorbs the heat that would have passed through the glass through radiation. Sort of burnt my fingers on one earlier but I was quick. I think it just about melted a micro fiber cloth when I used that to pull them.
The original 6L6 and 6L6G were rated identically and lower than the 6L6GC. There was also a 6L6GA which like the 6L6G had the ST-14 "Coke bottle" envelope and the 6L6GB which like the 6L6GC had the ST-12 straight glass envelope.
Absolute maximum plate voltage went from 360V to 500V and plate dissipation from 19 to 30 watts between the 6L6 and the 6L6GC.
6L6/6L6G datasheet: https://frank.pocnet.net/sheets/049/6/6L6.pdf
6L6GC datasheet: https://frank.pocnet.net/sheets/049/6/6L6GC.pdf
If the amplifier nameplate specifies 6L6GB or 6L6GC, you risk running a 6L6 metal or 6L6GA tube above its ratings depending on the design of the amplifier.
I'd examine the base of the metal 6L6 that shocked you under a magnifier. See if there's a carbon track in the base between pin 3 and the case. If so, that's probably the cause of both the noise and the shock.