I took my tube tester out of the shipping container to Costa Rica. The customs did break the glass of the meter and I am replacing it. And thought to share some pics and information now it is on the table
Tube testers are quite difficult to get in Europe and expensive. In addition, they are in general not suited to test tubes at a bit more power.
So I made my own using the cheap (nice) DVM's from China and all switching power supplies. The general power is supplied by a wide range switcher of 200 Watts from China delivering 32 Volts. From there I use a current boost converter for the filament ranging from 1.2 - 30 Volts at approx 50 Watts max.
The anode and G2 supplies by two home build switchers ranging from 20 - 350 VDc. Anode max 120 Watts, G2 50 Watts
The grid supplies are made by a home brew switcher delivering + / - 100 VDC
All supplies are continuous short-circuit proof without overheating
Every grid has its own small DVM and helipot to adjust the voltage from -100V to +100V (4 grids)
The anode and g2 supplies have also a DVM.
The anode current is measured by an analog meter with 5 ranges, 3 mA, 10 mA, 30 mA 100 mA and 300 mA. This meter has a switch to switch over to G2 current.
The G1 supply can switch a 1 MOhm resistor in series to measure gas or grid emission.
In order to avoid oscillation, all wires to he tube bases have at the end of the connection wire a series C and R to ground to damp the Q of an eventual resonance.
I added also a DVM to measure directly trans conductance. I did this by injecting approx 0.5V block to the grid supply and measure with a synchronous home build meter circuit the AC current in the anode circuit.
The socket connections are selected by 8 x 11 position switches and two switches can interconnect every pin with an other. The central contacts of these switches are, GND, GND, Filament, G1, G2, G3, G4 and Anode
In addition there are 9 x 2 mm sockets to make more interconnections or measuring points and a ground socket. Every socket is connected to a pin of the tube socket field. So when there is a double triode or so, I can connect he tubes in parallel. There are 2 connections available for top caps at tubes.
Was fun to design and build and the tester did serve me quite well. The trans conductance meter is nice to match tubes
When my shack is ready again, I will test all tubes in my sets. Fun job and keeps me out of the bar