Quicksilver 88 Operating Instructions - page 2
TUBES
The 12AX7 and 12BH7 input tubes are chosen for their specific performance characteristics and
should last several years or many thousands of hours. We can only guarantee the performance of
this unit when used with input tubes supplied by Quicksilver.
Each Silver 88 Amplifier is shipped with 2 matched KT88 output tubes. Best performance will
result when both tubes are matched by Quicksilver Audio.
Output tubes willneed to be replaced periodically. When a degradation in sound occurs or the
fuse blows repeatedly, it is time for new output tubes. We recommend purchasing tubes from
Quicksilver Audio or your dealer, and we recommend keeping an extra output tube on hand in
the event that one fails.
OUTPUT TUBE BIAS SETTING
Output tube bias should be set immediately when new tubes are put in; then again in 15 minutes;
and periodically the first few times of using the amplifiers. After that the bias should be checked
monthly.
Recommended bias is 40 ma and should be set the same for both outut tubes. Do not adjust the
bias while music is playing as meter damage could result.
Bias controls are behind each tube. To check the bias push the button in front of the tube you want
to check and note the reading on the meter. Each tube corresponds to the black button nearest it.
The amp may sound a little better with higher than 40 ma bias on some speakers and lower than
40 ma bias on others, however the bias should always be the same on each output tube.
To adjust the bias you will need a slot-head screwdriver. Adjust by turning clockwise to increase
bias; counterclockwise to decrease bias. Do this for each of the two output tubes. The two controls
interact so each control will need to be adjusted several times. Actual bias is shown on the bias
meter. Tube biases should be checked individually.
POWER SWITCH
shown in
BLUE
INDICATOR
SPEAKER
TERMINALS
INPUT
CONNECTOR
4 AMP
IEC
12BH7
OUTPUT TUBES: MATCHED PAIRS OF KT90 or KT88
Bias Meter
Bias Adjustment
Push to read meter
12AX7