• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Mercury 1000/2000 KT-88 and 6l6 design bug

Well it turns out that the Mercury 1000/2000 has a design glitch. It can test 5881, el34, 8417, 6550's for transconductance, but seems to only offer emmissions testing for KT-88's and 6l6's.

A lot of folks are just using 5881, el34, 8417, 6550's settings and changing the load, to test KT-88's and 6l6's for transconductance.

Having played around with this whole family of tubes recently, my first thought was that the tester can not handle the current of a kt-88 or 6l6.

I took a look at the schematic and don't think it's a voltage bias problem since the tester can test 8417's. The schematic is available here to large in size to post

Pacific T.V. - Online Schematics

So my thinking is that it's a transformer current problem. WOndering if I add a 15 volt transformer where indicated, if that would help?

Also thinking, sure I'll have to re-calibrate, maybe I can plus up the bais DC quality using bigger caps, which might get me some more current for a short term test.

Anyone cross this bridge?