The 6973 vacuum tube replacement

[Opcom]

Recently I had to suggest replacements for the 6973 tube @ 300V plate.
The 6973 is a 9 pin miniature tube used mostly in push pull audio circuits, but can show up anywhere.

The replacement choice was left to the client, but here is a chart of 6 possibly relatively inexpensive tubes that can work in the same circuit with similar performance. May as well submit it here since for my own use it's an ephemeral document. Possibly move it to the reference material area?

[KA3EKH]

I would replace it with a 6AQ5, would require a different socket and maybe something like a 6BQ5 would look better but the 6AQ5 has the benefit of being just about the same as the original tube and common as dirt.

[Opcom]

The client chose the 6CZ5 - did not want to make an adapter or re-socket, but I agree on the 6AQ5. Great tube in many ways!