Peavey VB-3 Operating Manual page 27

NOTES ON TUBE REPLACEMENT
WARNING! Never use ANY power tube type other than EL34, 6CA7, KT77 or 6L6GCs. Doing otherwise may
result in damage to the amp, unpredictable performance, and/or electric shock.
-Use or specify a matched octet (8) of EL34/6CA7 or 6L6GC power tubes, depending on the setting of the
internal bias switch.
-Have the bias set by a professional. This should be done every time ANY of the power tubes are replaced.
If the bias is set wrong, the amp will not put out maximum power, the output will be more distorted, and
the tubes may not last as long. If you are having it re-biased for use with 6L6GC power tubes, you should
expect to get about 240 W (rms) of clean power output, instead of the 300 W with the standard EL34
tubes.
-It is perfectly normal for power tubes, like the EL34 type used in the VB-3, to emit a soft blue glow.
-It is widely accepted that new-old-stock (NOS) vacuum tubes are superior, but this is not always the case.
While there are fantastic antique tubes available, they are rare and very costly, and in reality, the actual
benefits you receive are minimal.
-The eight power tube heaters are connected in complementary pairs, as depicted on the rear panel. If
one filament fails, its complement is disconnected as well, resulting in less power while maintaining bal-
anced current through the power amp.