Sovtek 5881WXT bias

[nashvillebill]

Now that I've gotten my Peavey Triumph 60 back up and running...I've tried setting the bias with my scope but it's awfully hard to see the crossover notch disappear.

So Plan B is the output transformer shunt method. Meter is a Fluke 179, should be accurate enough.

Plate voltage is around 500. Tubes are Sovtek 5881WXT, so I have no clue what plate dissipation to set them at. (I'm no expert but apparently they're not really the same as a 6L6GC).

Any advice would be greatly appreciated! Thanks!

[Gtr_tech]

Treat them as 6L6s. Somewhere around 19w would work fine. CAreful shunting the transformer.....one slip and you'll be treated to a fireworks surprise....or worse. WHen yer meter's set to read current its basically a piece of wire.....safety first.

[ThermionicScott]

From what I know, the WXTs are just the 5881/6L6WGCs with a full base. One of mine glowed at about 23W so I'd take that as an upper limit. They do seem to take high voltages well, though.

[Zouto]

Well, I usually bias 'em slightly colder, 17-19Watts, 33-36mA/5881 for 500V at plate.I think those Sovteks can stand quite a bit of overdose....

[nashvillebill]

Thanks guys, evidently my two tubes aren't well matched. I biased one tube at 40 mA (at 500 volts) and the other tube shows around 33 mA. (Follows the tubes if I swap them) Shows a clean sine wave though.

The sine wave started clipping around 19.5 volts RMS into 8 ohms which would be around 47 watts output...