I recently discovered a few of these cool-looking ST glass equivalent of a 6SN7 in my tube stash. This tube plugs into an octal socket but has different pin outs (vis a vis 6SN7) and requires a 1/4" grid cap for the second triode section. So I rewired the line stage section of my JEL mono preamp to use it.
|JE Labs Mono Preamp|
6SL7 + 6F8G
Not sure if it sounds better,
but it certainly looks a lot better ;)