[AdrianH]

Just ordered 100 ferrite beads to go over the wires, I am assuming it is fill up the wires and not just one bead per wire?

I was considering doing a PCB for the 4 sockets and including decoupling caps and inductors at each valve socket, but with different valves having heaters on various pins, some going over an amp current it started to get a bit daft.

Not sure if you can see the last picture underneath the tester in enough detail, the thin blue/brown twisted cable is connected to the 2 x PP3 batteries to the ends of the 5K pot, there is a 10uF cap across the wires and the output is co-ax going to the grid socket.

Must spell switch correctly next time.

When I have been testing I will always start at -18 Volts and wind up, typically with the EL84 or a PCL 86 when I get an anode current above7 or 8 mA off it goes into oscillation.

I will gladly take a vale off you if I need one but not if I don't? Not sure what you mean by a DC standardized valve and why that should be any different (apart from characteristics) then say a 30FL1, EL84 etc. Unless you mean you can state the characteristics out before sending it down so that I can check for the same?

The analogue meters have been adjusted to be within a couple of % with my digital meters both on volts and mA, I like analogue as it is easier to see what is happening and to know the difference between a gm of around 7mA/V or 6.9mA/V is overkill. But I will pm you but only send a valve if you think it is necessary, and thanks very much for the offer.

Adrian