[Doris The Diode]

Hi Everyone,

I have just completed the Sussex valve tester and because it is a cut down version on the original Sussex I've called it 'The Sussex Junior' - I hope I'm not busting any rules on the forum and it's OK to call this one 'Junior' and to post it here as part of the Sussex legacy.

I wanted to build a well designed tester but for it not to be as complicated as the original Sussex so I cut down on a few things but still leaving a very capable tester that can still do almost everything the Sussex can but all be it, in part 'manually'.

Electrically the HT & Screen circuits are the same and the grid circuit too but with a zener clamping the voltage to -20V as my meter from a far Eastern country only goes down to 20V.

What is different:
1) There is no gm oscillator or meter.
2) There are no dials but instead banana plugs for selecting different combinations of valve pins
3) The continuity test is done manually and there is a LED for this purpose.
4) I have taken all relays out.
5) There no other voltages for the heater apart from 6.3V.

Points worth mentioning:
1) I discarded the gm function as I can vary the grid voltage by half a Volt above and bellow the spec grid Voltage which will give me the same result as with a gm meter. I also had a small project box and could not fit the third meter in so went without.
2) I decided to use banana plugs as I did not have any room for dials, this was also simpler too construct.
3) I didn't want the complication of the continuity tester and also wanted to test every possible pin combination so I added a LED and it is checked manually.
4) As I didn't have the continuity function I took all relays out even the HT one and used a suitable switch instead for the HT.
5) As most of the valves I test are 6.3V I left it at just that. I have a bench supply which would give me all other voltages as required especially for the likes of UL41 etc... 100mA heater valves.

The 'Junior' might appeal to someone who has either a small project box, wants a smaller form or just wants a simpler to build tester but with the same proven HT, Screen and Grid design and is not too worried about doing some manual checks.

I have included some pictures testing a 6L6 and also using the heater voltage and the LED for continuity/shorts.

I'd like to thank Ed Dinning for winding the transformer, great work Ed and works well!

Happy building,
Berni