7059 tubes? Any potential for audio purposes?

[Opry Audio]

I got a huge lot of NOS 12AU7, 6SN7, 6L6, 12AT7, and 6V6 tubes. About 10 7059 tubes were included also. I know these were used in ham radio receivers, but is there any potential for audio purposes? Triode on one side and pentode on the other with a 12v heater supply. Maybe some kind of preamp or buffer? I couldn’t find much info besides a datasheet! Curious if anyone has used them for anything interesting. Thanks!

[tubeswell]

Pentode is only good for 2.8W Pmax. See last couple of pages in this (multi-tube) datasheet


https://frank.pocnet.net/sheets/191/6/6201.pdf

[Merlin]

A very ordinary 2.8W pentode and a very ordinary 2.5W triode in one bottle. You could use it for practically anything!

[danhei]

A common use for those pentode-triode tubes in audio circuits is a pentode gain stage DC coupled to a triode cathodyne phase inverter. Examples: Dynaco ST70 (7199 tube) and the Sunn 200S (6AN8).


Looks like your 7059 is related to the 6U8A. The latter has been used a substitute (with an adapter socket) by Dyanco and other users once NOS 7199 got expensive.

[Opry Audio]

A common use for those pentode-triode tubes in audio circuits is a pentode gain stage DC coupled to a triode cathodyne phase inverter. Examples: Dynaco ST70 (7199 tube) and the Sunn 200S (6AN8).


Looks like your 7059 is related to the 6U8A. The latter has been used a substitute (with an adapter socket) by Dyanco and other users once NOS 7199 got expensive.

Thank you for these examples. According to the datasheet 6AN8 is very similar with some spec differences in plate voltages and amplification factors / heaters. The 12v heater makes it a little trickier to use in a regular amp topology but may attempt to make a lowZ preamp of some kind?

[kagliostro]

To have a 12v heater power section there are tubes like 1625 (same of 807 or 6L6), GU50 and others

But a PP or a PSE of 6.3v with heaters connected in series can simply solve the problem

Franco

[Opry Audio]

You think I could get 12v of clean ac with a simple voltage doubler?

[kagliostro]

Doubler give you DC, not AC and require a lot of extra AC current

Assuming you simply want to go DC instead of AC you'll obtain (around) 600mA DC from a disposable 1000mA AC

The more, when you use a doubler the DC current will halve so from 600mA you'll obtain only 300mA (from the original 1000mA disposable on AC)

Find and use a 12V transformer, one of those for illumination lamps

Franco

[Joel]

With 12AU7 and 12AT7 - AX84 "Clean Preamp" or "Clean Preamp with added gain" depending on your application.  Combine with any 6V6 SE or PP output stage... Nice sounding amp.  https://el34world.com/Forum/index.php?topic=29299.msg343303#msg343303

[danhei]

You think I could get 12v of clean ac with a simple voltage doubler?

You just need a power transformer with a 12V winding for the filaments, which will supply the 7059 and any 12A_7 tubes. Pairs of 6.3V power tubes can run filaments in series on 12V as kagliostro said. Or if you can’t find a suitable power transformer with high voltage plus 12V for filaments you could use a secondary 12V transformer. Or you might find a transformer with dual 6.3V secondaries you can add together.


Lots of options