17-07-2015, 09:39 PM
So, some Valve Tests. A quick lash-up with a couple of PSUs and Meters suffices. Further to another Thread it's quite easy to do provided you have the bits.
14B4-A, the Series Regulators, first.
Herewith the Data:-
12B4A.pdf (Size: 231.06 KB / Downloads: 13)
With Va = 150 Volts, Vg = 17.5 Volts Ia measured 30mA against 34 mA - 88%. That should be OK.
6U8 next.
Data:-
6U8A.pdf (Size: 616.54 KB / Downloads: 15)
Pentode Section first:-
With Va = 125 Volts and Vg = -1 Volt Ia was 9.8 mA against 9.5 mA, so that's 'New'.
Triode Section:-
With Va = 125 Volts and Vg = -1 Volt Ia was 9.8 mA against 13.5 mA, which is approximately 72%
So, the Triode Section is a good bit low which might be significant.
I'll order one while I investigate other Components. There are several ancient Capacitors in there which will bear investigation.
Alan
14B4-A, the Series Regulators, first.
Herewith the Data:-
12B4A.pdf (Size: 231.06 KB / Downloads: 13)
With Va = 150 Volts, Vg = 17.5 Volts Ia measured 30mA against 34 mA - 88%. That should be OK.
6U8 next.
Data:-
6U8A.pdf (Size: 616.54 KB / Downloads: 15)
Pentode Section first:-
With Va = 125 Volts and Vg = -1 Volt Ia was 9.8 mA against 9.5 mA, so that's 'New'.
Triode Section:-
With Va = 125 Volts and Vg = -1 Volt Ia was 9.8 mA against 13.5 mA, which is approximately 72%
So, the Triode Section is a good bit low which might be significant.
I'll order one while I investigate other Components. There are several ancient Capacitors in there which will bear investigation.
Alan
