OPERATION
1. Connect your speaker leads and input cable on the amplifier, making sure the power
switch is in the “OFF” position (down).
2. Using a long-handled slotted screwdriver, rotate all of the adjustment controls fully
counter-clockwise.
3. Turn “ON” the amplifier. After approximately 5 seconds you should see an orange glow
appearing inside each tube. Wait one minute, then turn the selector switch knob on the top surface
of the chassis to the far left position (fully counter-clockwise). Now insert a flat bladed screwdriver
into the front left bias control slot and slowly rotate the control clockwise while observing the front
panel bias meter. Adjust the control until the meter pointer reads “40” on the meter scale. Now
rotate the selector knob clockwise to the next position and adjust the left rear bias control for a “40”
reading on the meter. Continue the same procedure for the remaining two output tubes, rotating
the control clockwise. When you have adjusted all four tubes to the “40” position, return the selec-
tor knob to the middle “12 o’clock” position (the indicator mark on the knob should be pointing
straight towards the back of the amp.) The first time you use the amplifier, you should recheck the
bias settings on each output tube after about 30 minutes of use (when checking, please ensure
that there is no signal going through the amp). Adjust if necessary. Periodic checking is needed for
all future use.
Your SFS-40 amplifier is now ready for use.
NOTE:
The “40” position on the meter scale biases each output tube for maximum sonic
performance and longest tube life. The red mark on the meter scale at the “50”
position indicates the absolute maximum that the EL34 type tube should be run at
(running this tube type at “50” will drastically shorten the life of the tube without any
redeeming sonic advantages). The “50” position can be used, however, if 6550(a),
KT88 or KT90/KT99(a) type tubes are installed.
CLEANING
The beautiful stainless steel (non-magnetic) finish of the chassis and transformer top covers will last
for years. A regular dusting with a soft, non-abrasive cloth will generally keep the finish looking like
new. Fingerprints may be removed with a small amount of silicon spray, such as WD-40 TM. Be
sure to apply any liquid into a soft cleaning cloth, not directly onto the chassis. At no time should
you allow any liquids to drop onto the amplifiers; it may run into the electronic circuitry underneath
and cause damage which will not be covered under your warranty!
