A simple Valve Test Jig

[AlanBeckett]

The Data Sheet I looked at called for 360R in the Cathode. Of course that's a Value I hadn't got so it got 363R - 330 + 33.
I just stuck a 10k from G1 to 0v and 1k in the G2.
If anything untoward had shown up I'd have investigated further but it didn't and it was only meant as a rough Check of the Valves and the Box.

Alan

[pwdrive]

I can see the attraction of a unit like that.

Lawrence.

[AlanBeckett]

Get bashing young Lawrence
It would be just as easy to put the bits into say a Diecast Box but I had the Ally and I like making things.

Alan

[oceanobsession]

Hi ,  I would like to test the  el84  valve in this manner , would I use class a data , and what voltages would I need to find ac or dc , which resisters , I have a fluke multimeter to measure  anode current , would I need another multimeter   can anyone help with a wiring diagram
cheers phil.

[AlanBeckett]

Hi Phil,

It really depends on what you want to achieve and what tackle you have to hand.

For a start have you got the Data Sheet? - http://www.r-type.org/pdfs/el84.pdf

You're going to need a High Voltage Source - around 250 Volts - and a Heater Supply - 6.3 Volts (ac).
However, you can generate the 250 Volts from a Transformer, Rectifier and smoothing. Suitable Transformers usually have a 6.3V Winding. Something simple like this would do - http://www.ebay.co.uk/itm/Philips-HT-TRA...2ee7375b4b.
Alternatively you can supply the Hetare from a 6v Battery.
You'd need a couple of Electrolytics and a Resistor for smoothing.
If you have an old Radio or Amplifier then you could tack on to the Supplies from that.
After that, if you only want to measure the Emission, you just need a Valve Base and a couple of Resistors, plus your meter.
So, what have you got and what do you want to measure?

Be careful.

Alan

[tiv48]

Found this may be of interest.
http://www.valvewizard.co.uk/valvetester.html
Rob T

[ppppenguin]

Ouch! I know the guy said his basic design was unsafe but it's ******* lethal. Pair of headphones floating at half mains? Lovely, just what I want around my head.

[AlanBeckett]

There's nothing new under the Sun


  Valve Tester.pdf (Size: 2.98 MB / Downloads: 48)

Alan

[oceanobsession]

Thanks alan , ive got a fluke multimeter , and a twin power supply 30v 2 amp , 2 meter jobbie , soldering iron , I can make the case and cut out the holes no problem

its my knowledge that is lacking a bit , I'm looking to test the el84 valve 
is the transformer you recommended 270v  dc  or  ac  

I think the test conditions for the valve are
6.3 heater
250dc
250dc
7.3 neg voltage to control grid

and I think some resisters are needed to take the measurement in mv

Thanks for your help ill come back when ive educated myself a bit more

me phil.

[oceanobsession]

Test Conditions
250 Va
250 Vg2
Ia = 48 mA
Rk = 135 ohms
170 Va
170 Vg2
Ia = 70 mA
-12.5 Vg1

el84