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4, Adjusting: If all the valves are high or low, set the
500mv by inserting a small screwdriver in each adjuster.
If one valve is significantly higher or lower, then it may
be faulty or life expired. The adjustment is very sensitive
so adjust very carefully. If the reading appears a little
unstable this is normally due to mains fluctuations.
5, If one or more valves are showing erratic readings or
you cannot set the 500mv, then that valve is probably
faulty or out of specification. If you are unable to set the
reading high enough this means the emission of the
valve is low.
NOTE!
If there is no reading at all the internal 315ma fuse
individual to each KT90 should be checked by a qualified
engineer. Spares should be located inside.
8 Valve Replacement
Important!
Do not attempt to change the KT90
output valves without reading these notes. Failure to
do so could be both dangerous and damaging to the
amplifier. Keep these notes handy.
Take care that you orient the valve correctly before
inserting. Line up the centre “Spigot” first.
Health & safety; High voltages are present inside the
amplifier and on exposed valve sockets when valves
are removed, so take suitable care. It is not
necessary to remove the bottom cover. Beware
valves get hot in operation!
5, Changing valves: If possible check the bias setting
before you attempt to change the valve(s), in order to
familiarise yourself with the procedure.
If changing all the KT90s be ready to adjust the bias in
order not to overload the power supply.
Don’t worry how
low the reading goes this will not cause damage. Do final
adjustment when the amplifier is fully warmed up.
If all is well there should be no more than a barely
detectable hum from the speakers, and the amplifier
should sound OK when tested.
6, If you cannot set up 500mv, then the valve is probably
faulty or is unsuitable. (if the reading is zero the
individual fuse may be blown).
If the valves are brand new, you will need to check again
after approximately 10 & 100 hours, after that only
occasionally or if you suspect a problem.
7, To avoid damage to the amplifier and electric
shock hazard you must use only valves marked
KT90, KT88 (6550), KT66, 6SL7, 6SN7.
Use only valves
which you know to be new or good condition and test the
amplifier thoroughly before resuming normal use.
8, Replacing the small valves:
6SL7 and 6SN7.
Neither of these requires any set up
procedure.
It’s just ‘plug and play’ although care
should be taken when removing and inserting not to
bend the pins. If this happens gently bend the pins
back into shape. (These valves are similar with the
same pin connection; accidentally interchanging
these two valves would not cause damage, buy may
reduce the amplifier performance).
Icon Audio are happy to check the valves/amp or re-
bias your amp free of charge.
6 Specification & Features
(Typical conditions @ 240v 50Hz)
•
KT90/88 output valves or eqv (/6550)
•
6SL7 double triodes for first stage
•
6SN7 double triodes phase-splitter
•
Hand wired point to point components
•
No printed circuit board
•
No tag board
•
Ceramic valve bases for low noise/leakage
•
HT delay circuit to protect cathodes (optional)
•
100w RMS (KT90) Ultralinear
•
50w RMS (KT90) Triode mode
•
Signal to noise level -90db
•
Freq response 20Hz-20kHz +or- 0.1db
•
Power bandwidth 10Hz-30kHz
•
0.1% THD
•
Custom hand wound transformers using
Japanese long grain steel
•
Choke regulated power supply inc output
•
Supplied with attractive safety guard
•
Minimal feedback used
•
High quality oversized metal film & wire wound
resistors
•
Audiophile High quality polypropylene audio caps
•
Japanese ‘Blue’ ALPS volume pot.
•
Internal wiring using silver gilt cable
•
Valves carefully matched for best performance
•
Gold plated Input & speaker terminals
•
400 mv sensitivity for full output (High)
•
1.4 v sensitivity for full output (Low)
•
230/240volts, 150watts (zero signal)
•
Standby switch function
•
3 amp T mains rear fuse (with spare)
•
400 ma F KT90 anode fuses (with spares)
•
W:20cm. D:50cm. H:22cm. Weight:22kg
•
IEC mains lead, (5amp fused)
•
CE certified. ROHS & WEEE compliant
Specification subject to change without notice.
