THD Electronics Flexi-50 - Manual (Page 9)

THD FLEXI-50 INSTRUCTION MANUAL 9
Biasing the Flexi-50 For Different Tubes
Power Tubes
One of the Flexi’s most exciting features is that you can very easily re-bias the amplifier
for new power tubes—either of the same type, or of different types. The Flexi can be
used with 6L6, EL-34, 6V6, 6CA7, 8417, 6550, KT-66, KT-77, KT-88, KT-90, KT-100,
EL-84 (with Yellow Jacket adaptor), 6K6, 6F6, and any other derivations of the above
tube types. You can even mix and match different tube types together, eliminating the
need for matched pairs!
Re-biasing the Flexi is simple. You’ll need a digital multi-meter, and then just follow the
directions below:
1. With tubes installed, power up the Flexi. Leave it in standby until the tubes have
heated up (at least 1 minute for most tubes, 2 minutes for 6550, KT-88, KT-90 and KT-
100 tube types).
2. Insert the black probe of multi-meter into the black socket (A).
3. Insert the red probe into the red socket for Tube 1 (B).