Advertisement
Tube Biasing
This is a simple yet important function of the back panel meter, the selector switch and the four slotted adjustment
controls on the back of the unit.
It is essential that the following procedures be followed before you turn on your SFC-1 amplifier.
1.
Connect your speaker leads and input source cables on the amplifier, making sure the power switch is in the "OFF"
position (down).
2.
Using a 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
through the ventilation slots on the amplifier cover. Wait two minutes, then turn the selector switch knob to the far
left position (fully counterclockwise). Now insert a flat bladed screwdriver into the LV4 bias control slot and slow-
ly rotate the control clockwise while observing the back panel bias meter. Adjust the control until the meter point-
er reads '40' (the red line) on the meter scale. Now rotate the selector knob clockwise to the next position (LV3)
bias control for a "40" reading on the meter. Continue the same procedure for the remaining two output tubes, rotat-
ing the control clockwise. When you have adjusted all four tubes to the '40" position, return the selector knob to
the middle "12 o'clock" position (the indicator mark on the knob should be pointing straight towards the top 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 - switch it to MUTE).
Adjust if necessary. We suggest that you check the bias settings every 3 months or so.
Your SFC-1 Control 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 "50" position can be used, however, if 6550(a), KT88 or KT90IKT99(a) type tubes
are installed. Under no circumstances should the amp be biased at more than "40" when using the
E34L/EL34/6CA7 tube type.
SYSTEM CONNECTIONS
NORMAL/DIRECT
Although most of the functions on your SFC-1 are self-explanatory, one function in particular should be explained. The
"NORMAL/DIRECT"toggle switch allows you to select one dedicated input (DIRECT) which will bypass all other front
panel switching (except MUTE and VOL for the greatest degree of fidelity. The NORMAL position is for all other less
critical inputs which you would like to have access to the BALANCE,MONO/STEREO and/or TAPE/SOURCE controls.
Use DIRECT for your most critical source material for maximum transparency and sonic performance.
OPERATION
3
Hide quick links:
Advertisement
