AVO Test Bridge CT8 valve

[Andrewausfa]

I have one of these with the L63 valve and another version has the 6B8G valve but I've just prised the back off of a recent arrival to find it has a CT8 base EBF2 in it. Has anyone else come across this meter/valve combination in their collection? I've not seen it mentioned in the various Test Bridge threads.

Number on the meter is 118-99 and to be clear is the old 30's-40's version.

Thanks - Andrew

[Andrewausfa]

Some photos in case they're of use for reference for someone in the future.

Andrew

[pmmunro]

This is the first item of ACWEECO equipment I've seen with a Mullard valve, so it's possible that it has been modified by a previous owner. Can you tell if this is likely from the way the valveholder is fitted and wired?

It would be an unlikely production modification as octal based alternatives to the L63 would probably have been more readily available. However, these bridges may have been made during the Second World War when supplies might have been erratic to say the least. I don't have enough serial number data to date your unit but there may be other clues inside.

PMM

[Andrewausfa]

Thanks PMM, I thought it was rather unusual and worth bringing to light though I didn't realise your point on Mullard valves.

There doesn't appear to be any signs of bodgery on the 'L' bracket the valve base sits on and to all intents it seems a production part. Looking at the exit holes and the paint around them, the two screws holding the base down seem to have been there from day one. The wiring and soldering around the base, though soldering's hard to tell of course, seems consistent with the other parts of the set and so seems original.

There are quite a few component changes looking at photos of the 'L63' version for which I'll have to get mine down from the loft for a more direct comparison.

Thanks again - Andrew