On 10/15/23 17:13, Tony Miklos via Jukebox-list wrote:
Working on a Seeburg JL with metal cased RCA 6L6's.
[snip]
The base must be a little small because the tube clips weren't grounding out the B+, although it may have been intermittently and that may have been the noise it was making.
The metal base tubes have a different profile than the glass based ones. Metal bases have a smaller indented main profile with little notches where the case is crimped on. Glass bases are larger and straight. The clips are to hold the tube in place. They aren't for grounding. That's what pin 1 is for on metal tubes and grounding obviously isn't needed with glass tubes.
The fact that pin 1 was not grounded on the amplifier tells me that it was probably designed for glass tubes. Is there a printed designator next to the socket, and if so does it just say 6L6 or something like 6L6G or 6L6GB ?