Inputs/outputs on old Bell tube amplifier

[ESigma25]

I've acquired an old Bell tube amplifier (model 3715-B) from the mid 1950s and it's got some rather...interesting input and output connections.

The inputs use some kind of modified UHF connector with no center pin hole:

https://i.imgur.com/8aegH4x.jpg

And the outputs use something that looks like a UX4 tube socket:

https://i.imgur.com/Rgp9s7B.jpg

Can anyone help me identify these connections so I can try and adapt them to something more standard?

[maxhifi]

Those inputs are standard for 1950s gear, get a Switchcraft 2501F to make an adapter cable. You could also just remove them and install RCA jacks or 1/4" jacks if it is more convenient.

The outputs are indeed a UX4 tube socket - Amphenol made plugs for these, and you can get a plug to make an adapter. Some amps of the era used UX5 sockets for speaker terminals too. If you want to modify the amp I'd suggest installing binding posts in parallel with the original output socket.

[ESigma25]

Originally Posted by maxhifi

Those inputs are standard for 1950s gear, get a Switchcraft 2501F to make an adapter cable. You could also just remove them and install RCA jacks or 1/4" jacks if it is more convenient.

The outputs are indeed a UX4 tube socket - Amphenol made plugs for these, and you can get a plug to make an adapter. Some amps of the era used UX5 sockets for speaker terminals too. If you want to modify the amp I'd suggest installing binding posts in parallel with the original output socket.

Yeah, I'd like to convert them to something normal, changing the outputs will be more annoying as they're riveted in so I might just use a plug to make an adapter.

What exactly is a "binding post"?

[maxhifi]

Originally Posted by ESigma25

Yeah, I'd like to convert them to something normal, changing the outputs will be more annoying as they're riveted in so I might just use a plug to make an adapter.

What exactly is a "binding post"?

https://en.m.wikipedia.org/wiki/Binding_post