A Simple, Valve Curve Plotter

[SurreyNick]

I am sure the uTracer is a fabulous piece of kit, but at 215 euros it isn't cheap and at present I don't need all that functionality and I may never need it. My budget is more like £30 quid and this thread is about designing and building a simple [static] valve curve plotter for this sort of budget.

To clarify the objective, it is: "To study the characteristics of triode and pentode valves manufactured pre-1936 and determine their constants by the characteristics."

Specification:
1. Ability to measure and plot the plate characteristics and the transfer (mutual) characteristics.
2. Tester to handle triode and pentode valves produced before 1936.
3. Be able to accommodate Battery and AC valves.
4. Handle valves with 1.5v, 2v, 4v, 6v and 6.3v heaters, anode voltages up to 250v, and GB voltages down to -30v
5. Tester to be powered from the UK mains supply.
6. Simple switch to alternate between triode and pentode valves.
7. Selector switch to select appropriate heater voltage.
8. Adjustable anode and grid voltages.
9. Current readings from integral milliammeter and plotted manually in Microsoft Excel.

This is more complex than I originally envisioned, but I believe it is within my ability and my pocket and that the functionality is likely to suffice for the receivers I plan to restore and build.

I do have one question.

From what I have read I believe it's acceptable for the purpose of these tests to use a DC only supply, even for AC valves. Is this right?
It will certainly make the circuit simpler if it is.

Thanks

Nick