Here's a brief list of some audio useful loctals, and their octal equivalent:

7A4 - loctal 6J5 (1/2 of a 6SN7GT)

7AF7 - mu of 16.5, very similar otherwise to a 6SN7 or 6CG7/6FQ7

7B5 - loctal 6K6

7C5 - loctal 6V6GT

7C7 - loctal 6SJ7 (or really close to it!)

7F7 - loctal 6SL7

7F8 - no equivalent, mu of 48, rp of 3300, twin VHF triode, used by jc morrison in his "Siren Song" preamp
as written up in Sound Practices.

7N7 - loctal 6SN7GT

7Z4 - fullwave indirectly heated rectifier, a bit more current capability (100ma./plate) than a 6V4/EZ80. Probably
make a nice preamp rectifier!

All the tubes above use 6.3 volts on the heaters!

Another possibility is the 14XXX series of loctals. Almost all the tubes above are available in 12.6 volt versions. There
is no 14B5 or 14Z4 though.

By using a 7F7 voltage amp, a 7N7 or 7AF7 phase splitter, and a pair of 7C5s as outputs, you can make a nice
push-pull all loctal amplifier! You can use a 7Z4 rectifiers if you don't go SS!

I have many of these tubes in stock, drop me a note if you are interested!

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