BVWS versus 'local' auctions

[Radio Fixer]

Had a look and some bargains

A22 at £200. AWA at £280 and more. AVO valve tester VCM 156 did well as expected at £800.

Gary

[Sinewave]

Just think about the amount of old valve testers which were scrapped years ago, little did anyone know how valuable they've become.

[Stockden]

Can you tell us why Hugh?

Well in simple terms, of the 30 items I handed over for auction only 12 appear to have actually been auctioned and the rest might as well have vanished without trace.

To be clear, where items were auctioned they were fully accounted for and the amounts raised were reasonable. I would have no concerns if this is what happened to all my items but it appears that most were actually sold across a table at Golborne, where the amount raised was pitiful. On querying this I was told that "we also take sales stock to the other BVWS events where there are no auctions" and "detailed information is only kept on item sales when it is an actual auction".  Thus I have no idea what each of these items was sold for or even if they were sold at all. 

This wouldn't matter if we were talking about a box or 2 of odd crystals but in my case it included a Tek 7704A 'scope mainframe, a Tek 7L13 spectrum analyser, a Solatron Schlumberger 7150 Plus 6.5 digit multimeter, a Marconi 2700 bridge, a CT471 Electronic Multimeter, and 5 Avometers (2 with cases). Any one of the first 4 of those should have raised more than the total amount I received for all of them and the decision not to auction them was, in my view, wrong.

So that is why I won't use a BVWS auction again. To be absolutely clear, I'm not suggesting that there has been any dishonesty by anyone involved but the process is not one that I wish to have any further dealings with and I won't be renewing my BVWS membership when it becomes due.

Hugh

[Jez]

Just think about the amount of old valve testers which were scrapped years ago, little did anyone know how valuable they've become.

One of the few types of test gear I don't have... and don't want! I was offered several FOC many years ago and had no use for them. One was quite impressive, Mullard I think, as it had punched cards like an anceint computer.

Ooo I think the quoting has worked OK this time according to preview.

[Mike Watterson]

I think the AVO 163 is more impressive. That Mullard is really for factories or checking the huge number of valves in a TV. It's a high speed tester, hence the cards instead of switches. The later good AVOs can be used to test any valve if you have the data, you don't need the AVO setting chart. Or if you have the pin out and a good guess at the heater voltage you can use it to work out the data for a valve. I'm pretty sure some computers still used punched cards by the time the Mullard tester ended production. The original was released in 1950 and the first ForTran compiler was 1956.
https://mullard.org/blogs/news/1950-the-...ary-design
Here is it is again. Not sure if the same version. The "??" means the date is a guess and it's too late.
https://www.radiomuseum.org/r/mullard_hi...ester.html
Better info here:
http://www.thevalvepage.com/testeq/mulla.../vtest.htm

An AVO CT160, AVO VCM MkiV or VCM163 are more use.

I also fitted an interface to a VCM163 so an Tektronix Transistor curve tracer could trace valves. Avo used for socket, pin assignment, heater and g2 volts. My friend has both.


They are of limited use, but a time saver, if you have the working gear because you can measure the in circuit currents to know about emission, or leakage to a grid. A 400V capacitor leakage tester can be used to test electrode leakage, hot and cold.

However while I've never needed one to repair/restore a radio, record player, tape recorder or amp I'd certainly use one to test bought valves on arrival to stock if I was building and selling amps. I'd relied on one in the local friendly TV shop in the late 1960s and early 1970s initially as I'd not realized the device itself could be used to test the valve.

I had a loan of this: https://www.radiomuseum.org/r/avo_valve_...met_2.html Undoubtedly very good.
I replaced the meter in this, https://www.radiomuseum.org/r/avo_valve_...er_mk.html or something similar, for a friend by using an op-amp and resistor to simulate the original meter and drive a 1mA meter with a new scale made by scan & edit of the original. I didn't have a posh expensive low offset instrument op-amp to hand so I built a stand-alone supply and same op-amp to derive a dynamic offset (to allow for supply drift) at input of the meter drive amp. So mechanical zero of meter without power and then preset offset & gain (save having to use precision resistors) to calibrate meter. No noticeable drift after initial setup.

I also looked at an old Hickock or something, a basic go/no tester that was pretty useless because many old valves won't have original spec emission and yet will be fine in use. Even as low as 20% or 30% can give acceptable performance in loads of old gear and some are hardly available such as an EBL31. The old go/no tester was also very limited on valve bases and voltages compare to the later AVOs (Maybe CT160 and later).


A curve tracer (and these are cheap now for valves) is more use when designing new gear if you have only limited data on the valves, or the data only assumes a particular HT. It's a bit slow for testing valves. https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
I have version one of that.

[Sinewave]

Just think about the amount of old valve testers which were scrapped years ago, little did anyone know how valuable they've become.

One of the few types of test gear I don't have... and don't want! I was offered several FOC many years ago and had no use for them. One was quite impressive, Mullard I think, as it had punched cards like an anceint computer.

Ooo I think the quoting has worked OK this time according to preview.

To be honest, I do have an AVO valve tester, I've never used it, so we can easily manage without one....

[Radio Fixer]

Thanks for posting Hugh: I can understand your discontent and hope that it passes with time. As you say most likely down to admin within the BVWS, after all they are all volunteers unlike an auction house with paid staff.

Gary

[Mike Watterson]

To be honest, I do have an AVO valve tester, I've never used it, so we can easily manage without one....

A good DVM and the little grey cells. Even the scope doesn't get much use for vintage restores. A vintage TV needs it the most. Used more for designing stuff. Hardly use the Grid dip meter (but it's misnamed as it has no valves). I'd use the spectrum analyser more than scope. The uTracer was interesting and more use than the borrowed AVO VCM163 for the rod pentodes (I used a separate filament supply). So I'd only see a use for valve tester if buying a lot of valves and reselling new gear regularly.
The signal generator is more use than scope or valve tester, especially during the daytime or on a multiband set. I had 455 / 10.7 Wobbulator and gave it away. Again it's more use on a production line than for repair or design work.