Two mystery valves

[kestrelmusic]

I've got two mystery valves which popped up in a job lot.

The first is clearly an output pentode; there are Pinout (octal base) is
NC - H - A - SG - CG - NC - H - K

6.3V heater, Ia=30mA, gm=2.5mA/V at G1=0, A=100, SG=100.

Could it be a 6F6 or even a dying 6V6?


The second is like nothing else I ever saw. It has a tubular envelope with top pip, three pins connected to the electrode structure. The outer electrode has SK122 stamped on one side and D4050 on another.

Pics attached - sorry they are not good but the best I could do.

Can anyone suggest an identity for them?

[Refugee]

That three connection one looks like a thermal timer for switching the HT on after the heaters have warmed up.

[Mr Moose]

Hello,

I think the four pin one is a spectroscopy lamp.

It is similar to this http://labshops.com/shop/product_inf...cjt53efa59uv37

Yours Richard

[Herald1360]

Interesting.....
http://www.photron.com.au/.assets/br...erium_lamp.pdf

[Marconi_MPT4]

Originally Posted by kestrelmusic

6.3V heater, Ia=30mA, gm=2.5mA/V at G1=0, A=100, SG=100.

Could it be a 6F6 or even a dying 6V6?

One method to identify for certain or narrow down which valve you have is to set up a bench power supply at 6.3V and measure the heater current.

Using Brimar data for reference the 6F6 is 0.7A , 6V6 is 0.45A, 6L6 is 0.9A

With the control grid (G1) set to 0V I would expect to see 6F6/6V6 with Ia of at least 80mA, so fair to say whatever it is, the valve is low emission.

Cheers
Rich