Page 7
7 Specification & Features
(Typical conditions @ 235v 50Hz)
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KT120/KT150 output valves
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6SN7 (6N8) phase splitter
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6SL7 (6N9) first stage amplifier
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0D3 150v regulator
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Hand wired point to point components
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No printed circuit board
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Ceramic valve bases for low noise/leakage
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94w RMS max one channe
l driven 8Ω KT120/KT150
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85w RMS* per ch Ultralinear
8Ω KT120/KT150
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42w RMS* per ch Triode mode 8Ω KT120/KT150
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65w RMS*
per ch Ultralinear 8Ω KT88
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36w RMS* per channel Triode mode 8Ω KT88
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Gain 75 (integrated) 27 (power amp mode)
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Feedback: 4db High sens, 14db Low sensitivity
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Signal to noise level better than -97db
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Damping F
actor= 13 @ 8Ω triode & power amp mode
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Freq response 20Hz (-0.2db)-20khz - 0db any power
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Full power bandwidth 20Hz (-0.2db)-55khz - 3db
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THD better than 0.2% any power
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4 and 8 ohms output taps
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Japanese grain oriented transformer iron
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LDT Low Distortion Tertiary output transformers
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Choke regulated power supply
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Supplied with attractive valve cover
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3 potted transformers to reduce transformer noise
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High quality metal film & wire wound resistors
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High quality polypropylene audio caps
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Optional Jensen Copper, Silver or Alu foil caps
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Japanese ‘Blue’ ALPS volume pot.
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Rubicon/Nichichron power capacitors.
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Audio wiring with silver PTFE cable
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Valves carefully matched for best performance
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Gold plated Input & speaker terminals
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Inputs for CD, Tape, Tuner, Aux
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Tape monitor output, buffered
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300mv sensitivity for full output (High sensitivity)
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950mv sensitivity for full output (Low sensitivity)
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230/240volts, 240watts (500 max @ full power)
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115/120volts, 240watts (500 max @ full power)
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3.15 amp (5A 115/120v) rear fuse (with spare)
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500ma Internal HT fuses (spares inside)
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440W, 400D, 230H
, 35kg (Allow space for
connections and ventilation)
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IEC mains lead, (plug 5amp fused UK)
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CE, ROHS, WEEE compliant
* Refers to measured RMS voltage across 8 Ohms. 240v/117v
at clipping point, KT88 use requires a lower HT tap.
(Specifications subject to change, errors & omissions excepted 30/08/19)
8. Bias Adjustment
This amplifier uses the technically supe
rior “Fixed
Bias” method of setting the output valve idle current.
For optimum performance and to avoid damage to
the amplifier please check this important function at
least once a month with the built in meter.
Most of the time no action will be necessary, but this
will give you the reassurance than the valves are in
good condition and working correctly.
For occasional checking:
The triode switch should be set to UL.
With the amplifier warmed up (15 mins) and with the
volume at zero, Rotate the bias knob to check V1,2,3,4.
This will measure the bias current and give a visual read
out. The optimum reading is when the pointer is in or
close to the black section of the dial (= approx. 47ma).
It is important to note that if all four valves read
slightly high or slightly low this is normal and may
be your local mains power variation.
If this happens
regularly the bias should be adjusted.
If one or more valves give unstable readings the valve is
probably faulty. This may be proved by swapping the
valves around, or trying replacement valves. In UK Icon
Audio will test your valves free of charge.
As the valves age the reading of each valve will vary.
This may be adjusted by slowly rotating the bias screw
for each valve until the reading is in the black mark.
A small flat blade screwdriver is all you need.
If you are unsure about any aspect contact your
retailer, Icon Audio or a competent service engineer.
You are welcome to speak to one of our engineers
by phone or email.
Most dealers and Icon Audio are happy to re-bias
and check you amplifier free of charge.
No reading at all (or 0) may mean a faulty valve or a
blown fuse s
ee “Valve fuses” under section 6.
Replacing the KT120/KT150s
Icon Audio are happy to replace valves and check to
performance of your amplifier, and advise on the
latest upgrades available. If you decide to do this
yourself please read the following notes first.
Important: Do not attempt to change the
KT120/KT150s without reading these notes.
Failure to do so could be both dangerous and
damaging to the amplifier.
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! Remove
power cable when changing valves.
Changing valves:
As new valves, will have a different reading it is
recommended that you change one, or one pair at a
time. Remove the first old valve and fit the
replacement. Switch on and measure and adjust
bias. Do not allow the reading to go above 100% as
this could blow the fuse.
Don’t worry how low the
reading goes this will not cause damage. Continue in
the same way and fit all four valves. 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 the pointer to the black mark, the
valve is probably faulty/worn or is unsuitable.
If the valves are brand new, you will need to check
again after approximately 10 & 100 hours. Regular
checking will ensure the amplifier gives the best
performance.
