Jasmine Concerto KT88-PP Owner's Manual - page 10
How to adjust Bias-Voltage_____________
After you exchange the power tubes ( like 6550, KT88 ),
you have to adjust the bias-voltage again.
The recommended Bias-Voltage is 0.50V ! Never over
0.52V, will cause the power tube burned down.
The lifetime of vacuum tube depend on the quality and
used hours each day. Usually, one set of tubes can be
used for 3 ~ 5 years. After you used Jasmine KT88-PP
for several years and find the sound quality degraded
markedly. It’s time for exchanging the tubes.
Some times, Audiophile like to change the different
brand of tube to obtain different sound.
KT88 = 6550
12AU7 =
ECC82=E82CC
The tubes are must pairs matched at least. The best is
four tubes matched each other.
1. Power off your Jasmine KT88-PP Tube Integrated
Amplifier
2. Waiting for the tubes cooling down to the safety
temperature, pull off the tubes
3. Plug in the new tubes, V1 and V2 is one pair, V3 and
V4 is another pair. For the preamp tubes, V5 and V6
is one pair, V7 and V8 is another pair.
4.
If you only exchanged preamp tubes (V5 ~ V8), the
exchanging operation is finished. No necessary to
execute following steps !
Why need to upgrade or exchange the tubes ?
The Exchangeable Tube Type
Step One: Exchanging the Tubes