[ARC5] 1626 tubes

[Brian A Clarke]

Hi Robert et al,

I wonder if the 1626 is an unusual tube?
The 1626 is approximately a 12J5 with JAN numbering and bulbous garb.
Usually a JAN numbered tube for 12 V heater operation is a 12 V version of a
6 V heater tube, eg, 1625 transmogrified from an 807.
However, the 6J5 is, AFAIR, a 6SJ7 with all the grids strapped together.
Whereas, when I look into a 1626, I don't see multiple grids.

Now, to reduce distortion, tube manufacturers try to get multiple grids
aligned
in the shadow of the control grid - but, I rather gather this was not the
case with
the 6SJ7, which was designed for maximum amplification. So, the 1626 may
not only be more rugged, but also have lower distortion than the 6J5/12J5.

Can anyone clarify?

And, Robert, the only other application I can recall for the 1626 was as an
audio
voltage amplifier in the ARC-5 modulator. If you have hundreds, I wouldn't
mind
just a few for getting some of my Command transmitters operational.

73 de Brian, VK2GCE.