Valve Testers - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

AC/HL · 25th Feb 2019, 8:45 pm

At one time valve boxes could be opened at one end in order to test them, without unwrapping, which could never be disguised.

methusela · 27th Feb 2019, 5:53 pm

Argus25 - Offence? Certainly not! Each to his own and we have more in common than you might think. Me? I also prefer devices with recognisable units (like the desirable AVOs) but, lacking either the money or motivation to restore one, might settle for a quick Good/Bad indicator like the Mighty Mite, which can be relied upon to catch about 80% of bad’uns, although requiring intelligence to interpret. A useful serviceman’s tool, no doubt, but the arbitrariness of their scales and the fact that different manufacturers had different ideas about what constituted Good/Bad means emission testers won’t provide much in the way of universally applicable data. Transconductance, on the other hand, relates to a quoted set of values supplied by the manufacturers. Furthermore, since Mr Steinbaugh seems not to be supported elsewhere in his assertion that emission is a good test of a valve’s state of health, I feel the need for a baking tin rapidly coming over me.

Radio Wrangler & TonyDuell – See the attachment for a British scale.

avocollector · 28th Feb 2019, 7:23 pm

Some time ago I bought a whole slew of earlier valves (47, 84, 36 etc) off an elderly gent and when I took them out I found they were all neatly labelled with emission % - ie 75% 67% etc. Sadly I did not notice this at the time I bought them and I rather suspect he is not longer around to answer how he got these figures - but it does argue for an emission tester with figures rather then just Bad ? Good scale.

25th Feb 2019, 8:45 pm	#41
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Valve Testers At one time valve boxes could be opened at one end in order to test them, without unwrapping, which could never be disguised.

27th Feb 2019, 5:53 pm	#42
methusela Triode Join Date: Jul 2014 Location: Wembley, London, UK Posts: 14	Re: Valve Testers Argus25 - Offence? Certainly not! Each to his own and we have more in common than you might think. Me? I also prefer devices with recognisable units (like the desirable AVOs) but, lacking either the money or motivation to restore one, might settle for a quick Good/Bad indicator like the Mighty Mite, which can be relied upon to catch about 80% of bad’uns, although requiring intelligence to interpret. A useful serviceman’s tool, no doubt, but the arbitrariness of their scales and the fact that different manufacturers had different ideas about what constituted Good/Bad means emission testers won’t provide much in the way of universally applicable data. Transconductance, on the other hand, relates to a quoted set of values supplied by the manufacturers. Furthermore, since Mr Steinbaugh seems not to be supported elsewhere in his assertion that emission is a good test of a valve’s state of health, I feel the need for a baking tin rapidly coming over me. Radio Wrangler & TonyDuell – See the attachment for a British scale. Attached Thumbnails

28th Feb 2019, 7:23 pm	#43
avocollector Heptode Join Date: Jul 2010 Location: Wellington, New Zealand. Posts: 653	Re: Valve Testers Some time ago I bought a whole slew of earlier valves (47, 84, 36 etc) off an elderly gent and when I took them out I found they were all neatly labelled with emission % - ie 75% 67% etc. Sadly I did not notice this at the time I bought them and I rather suspect he is not longer around to answer how he got these figures - but it does argue for an emission tester with figures rather then just Bad ? Good scale.