Decware TORIIMONO Owner's Manual page 18

O W N E R S M A N U A L
Added Notes:
BIASING - There are some important additional notes about biasing and output tubes that you
should understand. First is the bias "window". This means "range of adjustment" and primarily
concerns the rear bias control next the power cord jack on your TORII Mono's.
We have tried to define a window where the lowest bias setting you can achieve is 45 milliamps
and the highest setting is 75 milliamps. This was done in an attempt to make it impossible to
make adjustments that can either hurt the tubes or the amplifier. Unfortunately there are two
main variables that can have a large effect on this bias window. They are A) The tubes used and
B) the voltage at your wall outlet or power conditioner.
A) We ship these amplifiers with KT88 output tubes. The two favorites are JJ and
ElectroHarmonix. Pending the tube's specs and age, these tubes can cause your amplifier's
bias window to shift UP or DOWN.
B) Depending on the voltage at your wall outlet, which may vary during the day or when your
electric heat kicks on during the winter months, the bias window of your amplifier can shift UP
or DOWN. In this case, the window tends to follow the voltage. If the voltage is low (113 Volts)
you may see the window move down several milliamps. If the voltage is high (125 Volts) you
may see the window move up by several milliamps.
The combination of both A and B can cause the bis window to move by as much as 20 milliamps.
For example, a fresh pair of KT88's may bias up with the minimum adjustment of 60 milliamps
and a maximum of over 80 milliamps when the amp is plugged into an outlet when the voltage is
on the high side (125V). The same amp, with a used pair of KT88's when the voltage at the wall
outlet is on the lower side (113V) could cause the minimum adjustment to be 40 milliamps and
the maximum to be 60 milliamps.
THE ONLY THING TO REMEMBER REALLY IS THIS:
The speed limit is 80 milliamps. Try not to go over this amount.
The ideal bias setting is between 58 milliamps and 72 milliamps. Try to keep it somewhere
between these two figures.
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com