Uploaded May 2018 | Updated September 2026, 16 hours ago
We needed to test 15 EL84 valves (tubes), for go/no go status. We don't have a professional testing rig to measure gain/cathode emission so it was assumed, if the component under test would deliver the required output within applied voltage range, then they'd be serviceable when installed into an instrument. Our test gear: 1/. an HT adjustable power unit by Derritron No: S1001, 2/. a homemade signal generator having an ECC83 double triode and 3/. a wood/drawing pin means of temporarily soldering up EL84s to form a breadboard. To measure output, a German kit built Amtron power meter is used. Most of the 15 valves we tested worked satisfactorily. However 2 delivered only 4 watt, so were rejected as sub standard. Because the sig gen has an ECC83 that was easily exchanged, we tested all of: ECC81, ECC82 and ECC83 valves, that are all pin compatible. Type numbers ECC84 - 88 have a different heater arrangement so can't be tested in the unit. The numerically higher types will be a subject of a follow up YouTube submission. It should be stressed that this movie is presented for interest and curiosity only. Please remember that the relatively high voltages applied to these components can be dangerous.
CAUTION: There's a slight risk of fatality but more likely a very painful shock, through mistakes. It's happened to Hoofbag often in the past, compounding experience. Be careful and seek expert advice if you are of limited experience and want to repeat these experiments.
There are other parts to this testing series of movies in an account accidentally initiated by Liam Armstrong, since I was testing these valves for him, to sell on eBay. Goto:
youtu.be/ac1eFSp8y2E
We needed to test 15 EL84 valves (tubes), for go/no go status. We don't have a professional testing rig to measure gain/cathode emission so it was assumed, if the component under test would deliver the required output within applied voltage range, then they'd be serviceable when installed into an instrument. Our test gear: 1/. an HT adjustable power unit by Derritron No: S1001, 2/. a homemade signal generator having an ECC83 double triode and 3/. a wood/drawing pin means of temporarily soldering up EL84s to form a breadboard. To measure output, a German kit built Amtron power meter is used. Most of the 15 valves we tested worked satisfactorily. However 2 delivered only 4 watt, so were rejected as sub standard. Because the sig gen has an ECC83 that was easily exchanged, we tested all of: ECC81, ECC82 and ECC83 valves, that are all pin compatible. Type numbers ECC84 - 88 have a different heater arrangement so can't be tested in the unit. The numerically higher types will be a subject of a follow up YouTube submission. It should be stressed that this movie is presented for interest and curiosity only. Please remember that the relatively high voltages applied to these components can be dangerous.
CAUTION: There's a slight risk of fatality but more likely a very painful shock, through mistakes. It's happened to Hoofbag often in the past, compounding experience. Be careful and seek expert advice if you are of limited experience and want to repeat these experiments.
There are other parts to this testing series of movies in an account accidentally initiated by Liam Armstrong, since I was testing these valves for him, to sell on eBay. Goto:
youtu.be/ac1eFSp8y2E
