icon Audio Stereo 40 MK IV 6L6 User manual

Page 1
icon Audio
Instruction Manual Covering:
Stereo 40 MK IV 6L6
Contents
1 Introduction & Final Inspection
2 Quick Set Up Guide
3 Connecting inputs & outputs
4 Getting the best out of your amplifier
5 Trouble Shooting
6 Bias Checking & Valve Replacement
7 Specifications
8 Packing and Shipping
1 Introduction
Thank you for purchasing the Stereo 40 MK IV.
6L6. This version of the amplifier is specifically
designed to use the 6L6 family of output valves
which includes 6L6, KT66, 5881, 6P3 and
equivalents. The circuit is virtually the same as the
more powerful Stereo 40 KT88 but with lower
power and less features.
The Stereo 40 was first introduced in 2000 since
then it has undergone many refinements and
upgrades which make it one of the finest
amplifiers in its class capable of very high
definition when used with high quality input
material and loudspeakers.
In order to get the best out of your amplifier,
please read the enclosed notes thoroughly. Even
if you are experienced with Hi Fi please read the
‘quick set up guide’. Should you be uncertain
about anything to do with your amplifier please
contact Icon Audio or your agent for advice.
Valve (or Tube) amplifiers do the same job as a
solid state amplifier, but are very simple and have
a warmer, more pleasing sound. Your ears will
have become accustomed to your old amplifier, so
it may take some hours before your ears attune
themselves to the new sound. Also allow for a
“Burn in” period which may take up to several
months.
Setting up:
You will need at least one source such as CD,
Digital Streamer, Phono preamp etc, a pair of
suitable loudspeakers, interconnects, and
loudspeaker cables. (See section 2)
Site the amplifier where it will have adequate
ventilation away from heat sensitive materials.
Larger more efficient loudspeakers will give a
higher volume and deeper bass (90dB or more).
Some experiment may be needed to get the best
effect. Make sure that the loudspeakers are “in
phase” by checking the polarity at both ends of
the loudspeaker cable.
Your source, loudspeakers and room acoustics
will also affect the sound.
Setting up and judgements should be made with a
‘clean’ well balanced recording.
The Stereo 40 MK IV is a push-pull Ultralinear
stereo amplifier, using fixed bias. The driver and
phase splitting is all triode. The pre-amp is a high
quality ‘Passive’ circuit using high quality audio
cable and an ALPS volume control. It is sensitive
enough to be used with all modern source
equipment. Its simplicity coupled with point to
point hand wiring all add up to give exceptional
listening performance.
IMPORTANT!
THIS MANUAL CONTAINS
ESSENTIAL HEALTH & SAFETY
INFORMATION FOR YOU AND
YOUR AMPLIFIER. PLEASE
READ & KEEP SAFE AND
REFER TO IF NECESSARY
DRAFT COPY
May Contain errors!
With 6L6 & CV181
With 6P3 & 6SN7

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Final Inspection - Your Guarantee of Quality
To assure you of optimum performance and reliability, this amplifier has passed our rigorous
final inspection and listening test by the Icon Audio team in Leicester. During which the final set
up and adjustments were made.
Date …./…./….
Model ST40 MK IV 6L6
Amp Serial Number ……….
Customer ……………………………
Check amplifier finish ……….
Check valve cover ……….
Internal wiring check ……….
Triode mode conversion ……….
Run min 8 hour test ……….
Check all inputs ……….
Output Valve Bias level ……mv
Power UL 1 kHz 8Ω ...……L….…R
Sound Quality ……….
Channel Balance ……….
Valve Microphony ……….
Screwdriver included ……….
Hum level left/right ...../…..mv
RF Test ……….
Meter brightness ……….
Serial No sticker and recorded ……….
Mains voltage 117V / 230-240V
IEC Mains Fuse 1.6A…….
Internal HT Fuse 2x T250mA ceramic
UK Plug fuse 3A..…A
Mains lead in box ……….
Remote Control Function ……….
(only if purchased as an option)
Remote handset in box ……….
Bottom label ……….
Transformer Protection ……….
Output valve type ……....……….
Driver valve type ……………….
Mains lead ……….
Signed off by ……………………….
Checked by ……………………….
Notes:

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IMPORTANT READ THIS FIRST
2 QUICK SET UP GUIDE
Box contents:
Amplifier, Cover, 4x 6L6/KT66, 4x 6SN7, remote
control (option), mains lead, manual, screwdriver.
1 Unpack unit carefully and check that it is in
good condition. Report any transit damage to your
re-seller immediately. It is important that you keep
packaging for warranty/service return.
2 If Necessary fit the valves, or check that they
are firmly in place. The 6L6/KT66/6P3s should
be fitted first observing the numbers 1,2,3,4 on the
rear of the valve, corresponding with the four
sockets viewed left to right from the front. Take
care to line up the centre spigot when inserting all
valves. Do not push or pull the output valves
by the glass envelope, this could cause the
glass envelope to become detached from the
base, damaging the valve.
The four smaller 6SN7/CV181/6N8 valves are
fitted at the front. Again observe the position of
THE “spigot”. These are numbered 5/6/7/8. Fitting
the valves as numbered does not require any
adjustment.
Please note the 6SN7/CV181 are not
interchangeable with the 6L6/KT66 this could be
dangerous and will damage the amplifier.
3 Connect to source units, e.g. CD, Tuner,
Tape, Phono pre amp (if used) etc via appropriate
phono sockets.
4 Connect loudspeakers to the BLACK terminal
and either 4 or 8 Ohm RED terminals. (See your
speaker info). Make sure the polarity is correct.
(See speaker connections chapter). If ‘bi-wiring’
both black and both red leads should be
connected together. A second banana plug can
go vertically through the terminal hole.
5 Connect to mains supply using supplied IEC
mains lead to 230/240v supply (or 117v North
America). If for some reason the welded (fixed)
plug must be removed, remove the fuse and
dispose of immediately. (As they can be a
danger to children if plugged in). The replacement
plug should be wired in the following way Brown
to Live terminal, Blue to Neutral terminal and
Green/Yellow to Earth.
6 SWITCH ON! The meter should light up, the
valves will heat up. The amplifier will start working
within about 45 seconds. All valves should have a
visible orange glow from the cathode heaters.
With the volume control set to minimum (fully anti-
clockwise) there should be virtually no sound
coming from the speakers except a barely
discernible hum. If there are any unpleasant
sounds coming from the speakers, switch off and
refer to the ‘Trouble Shooting’ section or contact
your dealer or Icon Audio. When using for the first
time check the bias reading The pointer should be
in the black section (see section 6.2). Select
source required and adjust volume control.
7 Your unit should now be functioning. If not
check wiring again making sure the correct input
is selected and volume control is not at “zero”. Do
not operate at a high volume for the first five
minutes to allow the valves to warm up properly.
8, Remote Control. (Optional version) If there is a
plastic safety tab, loosen rear screws and pull out,
re-tighten screws. If the batteries are OK (2x AAA)
the blue LED should light when any of the keys
are pressed. A little skill is needed in pointing and
pressing, as the unit has a motorised “pot” which
may not be as responsive as your TV. Maximum
range is about 5 meters. System re-sets to 9
o’clock on switch on. Strong light may interfere
with operation. Batteries should be replaced every
two years to prevent leakage. Remove batteries
when amplifier is not in regular use to prevent
leakage.
Please note all these things are normal for
valve amplifiers:
A, Valves can get very hot, BEWARE!
B, The middle transformer will get “hand hot”.
C, The amplifier may smell slightly for a few weeks.
D, Occasional Mobile phone ‘breakthrough’ is
normal (move your phone away!).
E, Valves may make a ‘tinkling’ sound when
warming up and cooling down.
F, The volume control may sometimes appear to
sound ‘Scratchy’, this is not a fault!
G, Valves occasionally “Pop” or “Crackle”. If this is
regular problem it could be your heating
boiler/cooker/fridge etc. (see trouble shooting).
8 Health and Safety. The valves when operating
have high surface temperatures. Keep out of
reach of children and pets. The use of the
supplied guard is recommended in these
circumstances. Avoid situations where flammable
material such as paper or curtains may come into
contact with the valves. Always unplug when
making adjustments. Like all amplifiers there
are potentially lethal high voltages inside,
which when switched off can take a few
minutes to discharge! Do not remove bottom
panel unless you are a competent engineer.
There are no user serviceable parts inside. Like
other household electrical appliances do not
leave unattended whilst switched on. Do not
adjust the output valve grid bias pre-sets without
reference to the manual. Incorrect adjustment
could cause the valves to overheat, with resulting
in damage to valves and amplifier.
To maintain the best performance of the
amplifier you should check the bias of the
output valves regularly (say monthly using
built in meter). Full details will be found in
section 7.

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3 Connecting inputs & outputs
Inputs
The amplifier will work with any equipment having
an audio “Line Output” e.g. CD, Tuner, Phono pre-
amp, Streamer, Tape Deck, TV, DVD etc.
If you wish to use a turntable you will need a
suitable phono pre-amp. Icon Audio or your dealer
can advise you. One of our pure valve phono
stages is an ideal partner.
Connecting a tape deck/Recorder
A fixed output is available for recording purposes
which is unaffected by the volume control.
Playback may be made using one of the inputs.
Connecting loudspeakers
Use good quality loudspeaker cable. This should
be relatively thick and multi-stranded. e.g. QED
‘Classic” 79 strand 2.5mm is more than adequate
(for amplifiers up to 2,200W!) Take care to
connect the correct polarity. The use of ‘Banana
plugs’ or ‘spade’ connections will ensure a good
connection whilst minimising the risk of ‘shorts’.
In our experience valve amplifiers are very
tolerant of loudspeaker cables, therefore the
benefits of very ‘exotic’ cables may be wasted!
But this is personal taste. Icon Audio or your
dealer will advise you.
As all cables have losses, use less than 10m
each. You can either ‘hard wire’ your cable to the
amplifier by baring enough cable to fit in the
connector and twist together to avoid any spare
strands touching anywhere else (soldering the
stands together helps). Warning! this amplifier
does not have an output protection device,
which would degrade the sound. So a
prolonged short due to strands of wire
touching could damage the valves.
Alternatively use good quality ‘banana’ plugs,
once fitted they are trouble free.
Bi-Wiring
Not recommended but a matter of personal
preference. Connect your loudspeakers up as
normal. Take care to use correct polarity for both
bass and high frequency connections. The ST40
loudspeaker terminals will accommodate two
banana plugs, the second one vertically though
the terminal shaft.
Speaker polarity.
It is essential that you observe the polarity of
the terminals; they must be the same for the
left/right connections at the amplifier end and
at the loudspeaker end. Otherwise the sound will
be ‘out of phase’ with the sound stage ‘inside out’
with reduced bass. If you are unable to check
this or confirm the polarity (e.g. if you have
‘built in’ wiring), try the following; Connect the
system up and play some music with plenty of
bass (e.g. dance music), preferably in mono (most
1950’s recordings are mono) and stand the
speakers close together. If correct you should
hear plenty of bass, if not reverse the terminals
for one channel only, either at the amp or
speaker. You will now hear more, or less bass.
The higher bass output is the correct setting to
use. Another alternative is to use a test disc. If
you are ‘bi-wiring’ your speakers only two
terminals, you must use only 4 or 8 ohms, not
both, as this will not load the amplifier properly.
The STEREO 40 is designed to work with full
range, medium to high efficiency (ideally higher
than 93dB) having impedance of 4 ohms to 8
ohms. Speakers having efficiency of lower than
88db will have greater difficulty in providing a high
sound level. But this will also depend upon
individual speakers, room size, type of music and
positioning etc.
Speaker impedance. It is important to use the
correct speaker impedance terminals, as this will
give the best sound quality and power matching. If
using 15-ohm speakers use the 8-ohm
connections. If you are unsure or “6 ohms” or “4 to
8 ohms” is quoted; a rule of thumb guide is to try
both positions. 8 Ohms will sound a little louder,
the 4 Ohms position having a little more “weight”
in the bass end. Although your personal taste
should be the final deciding factor.
If two pairs of speakers are required to be
connected, they must both be 8-ohm and
connected 4 ohm terminals. Contact Icon Audio
for more information. Damage could occur if care
is not taken.

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4 How to get the best out of your amplifier
•Do not leave the amplifier switched on when not in use. Valve life will be reduced.
•Do not switch off and on without a short rest of 30 seconds.
•Do not adjust the output valve grid bias without reading section 6.
•Do not operate the amplifier without loudspeakers connected.
•Do not use valves other than listed as there could be danger of shock or damage.
•Do check the bias regularly at least once a month for best performance.
•Do make sure the speakers are in phase.
•Do use the best possible source material.
•Do use efficient, well-designed speakers.
Siting
The amplifier should be placed on top of a unit or
an open shelf where freely circulates.
What is safe maximum volume?
The Stereo 40 MK IV will run happily all day long
at a high volume; the valves are hardly stressed
any more than at zero volume. Running into
distortion will however stress the whole amplifier.
The maximum safe volume is just before distortion
occurs. However this will vary according to the
level and type of music played.
Triode Mode.
Normally the ST40 6L6 is in “Ultralinear” mode
which means the valves are used in 50%
Pentode, 50% Triode. This give 90% of the power
of pure Pentode with 90% of the characteristics of
pure Triode.
If requested the amplifier may be converted to
pure Triode with about 40% reduction in power.
Headphone Use.
A headphone amplifier may be connected to the
REC OUT terminals which will reproduce
whatever the selector switch is set to.
Leaving the amplifier switched on
Do not leave the amplifier switched on 24/7. Your
valves will be worn out in approximately nine
months! Whilst the amplifier will sound at its best
when it is properly warmed up, there is no
advantage leaving it switched on when it is not in
use. The valve types used give a fast warm up
and are fully working in 60 seconds.
We would always advise that any item of home
electronics is switched off when not in use
‘Burning in’
Although the amplifier should sound good
within about 5 mins it can take up to an 30
mins to sound at its best and will take several
months of regular use before it is fully ‘run in’.
Upgrading Valves!
Good quality new valves sound better, have good
performance and reliability. The upgraded valves
supplied with selected models are the result of
careful comparison with other makes. But beware
of paying excessive amounts for “New Old Stock”,
second hand valves. At this time we recommend
Genelex, E.H. Tung Sol, Psvane, JJ, which we
are happy to test and supply.
Cabinet Care
To remove dust we suggest gentle brushing of the
cabinet paintwork with a soft paintbrush. Other
marks can usually be removed with a damp cloth.
On no account use anything wet on the amplifier,
and always clean with the power disconnected.

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5 Trouble Shooting
Many problems associated with Hi Fi equipment involves
connecting leads, which are usually either ‘BAD
CONNECTION’ or a ‘WRONG CONNECTION’. So it’s
worth making sure that you have good connections and
that your leads are the right way round.
Also there are too many possible combinations of
circumstances to list all possible fault combinations here.
Common problems are listed below:
1. Amplifier Dead
Check the 1.6 amp (3 amp USA) mains fuse at the
back of the amplifier. To gain access, remove the
mains lead. The fuse is in a small plastic drawer,
which forms part of the socket assembly. To open
insert a flat bade screwdriver or similar and prise
open. The fuse in use is the innermost the outer is
a spare. Should the replacement fuse also blow there
is a fault. Replacements should be 1.6 (or 3 amp
USA) amp ‘anti-surge’. Available from Icon Audio free.
The fuse in the plug should be a 3 or 5 amp fuse,
although unlikely, this should be checked if the
amplifier fuse is OK, or another mains cable tried.
2. No sound
The ST40 is lit up but no sound from one channel.
And the bias reading is “zero” on that channel. This
could be one of the 250mA HT fuses which are
located inside the amplifier (its highly unlikely that
both will fail). Ideally an engineer would replace these
but if this is not possible DISCONNECT THE POWER
CABLE, invert the amplifier, remove bottom plate and
replace the fuse on the problem channel two spare
fuses are attached to the bottom plate. Also look for
burnt resistors on the 6L6s base as this could be due
to valve failure in which case the resistor which
protects the amplifier from damage will also need
replacing.
(Replacement fuses are available free from Icon
Audio in the UK).
If all four of the output valves have a bias reading
check:
Have you selected the right input?
Are the connections OK?
Is everything switched on?
Are the speakers connected?
One of the 6SN7/CV181/6N8 valves may have failed.
This may be proved by swapping from the working
channel.
If the problem persists the amplifier may need to be
serviced. Contact your dealer or Icon Audio.
Distorted sound.
Try another source; if sound improves then it’s probably
something wrong with the first source. If no improvement
try different speakers, if no improvement could be an
amplifier problem.
Hum Problems
If you experience hum, try disconnecting all inputs, if
hum persists this is probably an amplifier fault.
If not, identify which input is causing hum. Connect one
input at a time. A common cause is a ‘hum loop’ caused
by having too many earths, and may be identified by
unplugging each input source from the mains. One
remedy for this is to use an interconnect which only has
the screen connected at one end. Other causes of low-
level hum can be from adjacent equipment, so
experiment with moving equipment around to see if
this makes the hum better or worse.
Interference Problems
The amplifier design incorporates features and
devices which make it resistant to mains-born
interference. But some heaters, boilers, fridges,
cookers etc can generate intermittent RF (radio
frequency) interference which travels through the air
(and walls). Although rare this can be very irritating.
In this case a simple capacitor is often all that is
needed to effect a permanent cure (contact us).
One channel missing.
Usually ‘bad’ connection on either the input or the
speakers. Try swapping the connection over to
establish if the cause is:
(a) Input to the amp. Sound will move to the other
channel.
(b) Amplifier or speakers. Sound will not move.
(c) If none of these, check internal fuse for that
channel (see section 5.2).
Strange noises coming from speakers:
Turn volume to minimum on unused input, if the
problem is corrected either fault with source unit or
with connection. If noise persists, problem with
amplifier.
Valve overheating
If the whole output valve glows red (other than the
heater), often accompanied by a hum through the
speakers, switch off immediately, and refer to Icon
Audio or a service engineer, as this could be valve
failure.
A valve that is lit up is not a guarantee that it is
working properly; conversely a valve that is not lit up
will not be working (usually cold to the touch).
Valve Replacement (see also section 6)
Valve life will depend upon such things as hours of
use and number of on/off cycles, Do not switch on
and off unnecessarily. Also it is not good practice to
remove the valves unnecessarily as this can strain
the pins and cause tiny air leaks.
Service: Should you suspect a problem, you could
return the unit to Icon Audio for a periodic service or
return the valves for testing free of charge. You
should carefully remove the valves (the 6L6/KT66
should be held by the base when removing)
numbering them with a marker from left to right as
you do so in order that that may be replaced in the
same position. They should be well packed in
cardboard & foam or similar, and returned to Icon
Audio for testing. (Valves are very rugged if packed
properly).
Mains Supply
This amplifier is configured to work on 230/240v ac,
(or 117v USA, Canada) this may be changed over.
Contact us for more information.

Page 7
6. Bias Checking & Adjustment
If you are unsure about any aspect of bias contact
your retailer, Icon Audio or a competent service
engineer.
The Stereo 40 MK IV uses the ‘Fixed bias’ method of
valve operation. This has the advantage of higher power,
lower feedback and cooler running. However you should
regularly check the bias reading using the built in meter
to ensure best performance from the amplifier. This is
very easy.
1, Tools you will need:
A small flat blade screwdriver ( normally supplied).
2, How to read the meter.
If possible warm up the amplifier for 5 minutes, volume
at “zero”. Rotate the bias knob through V1-V4. This
corresponds with the rear output valves left to right
(viewed from the front). Each valve should have the
black pointer in or near the black section. (50-75).
About 10% percent difference ON EACH PAIR (1,2 and
3,4) will make little difference in performance.
Greater than this requires adjustment, especially if the
reading is 80 or more it should be reduced as this valve
is drawing too much current. Lower than 50 will cause no
harm but the performance will be reduced.
NOTE
3. The readings are affected by your local mains voltage.
So if they are all slightly high or low this is probably OK,
and check again later. If one valve is giving a high or low
reading adjust that one valve in line with the others.
4. How to adjust the bias:
Make sure you are reading the valve to adjust, e.g. read
V1 to adjust V1 screw. If the reading is incorrect, set this
by using the screw very slowly up or down until the
correct reading is obtained. They are very sensitive so
adjust very carefully. If the reading appears a little
unstable this is normally due to mains fluctuations.
You may need to repeat this a couple of times as the
adjustment of one valve may affect the other readings
slightly.
5, If one or more valves are showing erratic readings or
you cannot set the correct voltage, 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 too low. Normally adjustment intervals are
2-3 times a year or if you suspect a problem.
6. Possible problems: If the reading is unstable, 100%,
or “zero %” this is probably a valve failure, in which case
refer to your dealer or Icon Audio. Also the internal HT
fuse may have blown for 1&2 or 3&4 (spares inside).
When not reading bias, the meter on the front panel
gives an approximate power indication. (Full power both
channels in mono = 100%).
Valve Replacement
How long do the valves last?
In normal use about 5 years (5000 hrs) when they will
start to wear out. The quality and power will slowly
deteriorate. Sometimes the heater will fail and the valve
will remain cold to the touch.
Occasionally a 6L6/KT66 may suffer catastrophic failure
which may cause a noise through that speaker and
possibly over heating which may blow a fuse. In the UK
Icon Audio offer free valve testing if the valves or
complete amplifier is returned to us. The decision to
replace one valve or all valves will depend upon the
age of the remaining valves.
You are welcome to email us for advice or
replacement valves.
Replacing the 6L6/KT66 Valves
Important: Do not attempt to change the
6L6/KT66 without reading these notes. Failure to
do so could be both dangerous and damaging to
the amplifier.
When replacing valves, it is recommended that
you use a “matched quad”, or two matched pairs
for best performance.
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 normally necessary to remove the bottom
cover. Beware valves get hot in operation!
7, Changing valves: You should if possible check the
bias setting before you attempt to change the
valve(s), in order to familiarise yourself with the
procedure.
The safe way to change especially if they are a
different type is to change and re-bias one pair at a
time.
Remove the first pair of old valves and fit the
replacement pair. Switch on and measure and adjust
the bias.
The bias adjusters are “clockwise” to increase “anti-
clockwise” to decrease.
Make sure the selector is set to the correct valve!
Do not allow the reading to go above 95. 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.
8, If you cannot set up the bias then the valve is
probably faulty or is unsuitable.
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.
If the meter should go over 100% reading, switch off
and allow to cool down, on switching on the valve will
warm up slowly allowing time to make adjustment.
9, Use only valves marked 6L6/KT66/6P3 or that
you know to be direct equivalents. And 6SN7/6N8
for the smaller valves (V5,6,7,8).
Use only valves which you know to be new or good
condition and test the amplifier thoroughly before
resuming normal use.
EL34 and KT88 valves are not recommended
The new high power KT120/KT150/KT170 are not
suitable.
10, Replacing the smaller 6SN7/CV181/6N8
valves:
These do not require any set up procedure. It’s just
‘plug and play’, although care should be taken when
removing and inserting not to break the centre spigot.
If using two pairs of different brands use the outer
sockets for one pair and the inner sockets for the
other pair..

Page 8
Technical Notes:
Meter Function:
This is set to give optimum bias at 65% reading. When
reading power 100% = both channels 2x 28W or one
channel 50%. All continuous at 1kH.
*RMS watts Based upon the RMS voltage output (V²/R).
Indicates the maximum continuous undistorted output
power.
*Push Pull is a very elegant way of 2 valves in
opposition, virtually cancelling out non linear distortion,
noise and hum. Whilst dramatically increasing the power
and damping factor. In Class AB about 1/4 of the output
is pure class A. Unlike transistor designs there is no
crossover distortion at any power of the Stereo 40.
*Ultralinear (or Distributed Load). This is a true “win-
win” output stage design. Having virtually the all the
characteristics and low distortion of pure Triode valves,
whilst keeping 90% of the power of pure Pentodes types.
7 Specification & Features
(Typical conditions @ 235v 50Hz)
•6L6/KT66/6P3/5881 output valves
•6SN7/6N8 double triodes for first stage
•6SN7/6N8 double triodes phase-splitter
•Icon in-house designed and wound Ultralinear
output transformers with tertiary winding.
•Hand wired point to point components
•Ceramic valve bases for minimum noise/leakage
•28W x2 (6L6) at clipping
•Signal to noise level -85db
•Low Feedback of 8.5dB
•Frequency response 6L6:
•20Hz to 20kHz 8 Watts -0.2dB
•20Hz to 20kHz 28 Watts -1 dB
•Power bandwidth 20Hz to 60kHz -1dB 28W
•THD Typically 0.05% THD at 8 Watts
•THD Typically 0.2% THD at 28 Watts
•Channel balance typically less than 0.2dB
•4 and 8 ohms output taps
•Choke regulated power supply
•Supplied with attractive valve cover
•Audiophile quality metal film resistors
•Audiophile quality polypropylene audio caps
•Optional Mundorf Silver/Gold in oil upgrade
•Japanese ALPS volume pot.
•Internal wiring using PTFE silver plated cable
•Valves carefully matched for best performance
•Gold plated Input & speaker terminals
•Inputs for CD, Tuner, Aux
•Line level record output.
•380mV sensitivity for 28W output UL
•220-240volts, or 117v for north America
•150W “0”Signal, 170W Watts 8W output
•1.6 amp (3amp USA) AS rear fuse (with spare)
•250ma T Ceramic fuse internal HT (critical safety part)
•390mm W, 210H, 410D amplifier overall, 20kg
•Carton= 38x54x52cm 28kg packed
•IEC mains lead, (5amp fused UK)
•Conforms to CE ROHS and WEEE where applicable
Specification subject to change without notice.

Page 9
Our Guarantee to you
Icon Audio or your dealer guarantee this amplifier for
12 months from date of purchase. This covers parts
and labour. Valves are guaranteed on a 12 months
reducing balance basis as they are consumables.
We expect our amplifiers to give a service life of
approximately 20 years, with regular maintenance.
During this time we will make every effort to supply
spare parts and repair them at an economical cost.
Supply is subject to availability from third party
suppliers which Icon Audio is not responsible for.
This does not cover unique parts including remote
control systems, meters and cosmetic parts.
If you believe the unit is not functioning correctly, it
may be helpful to contact your dealer or a valve
(tube) amplifier engineer.
You are advised to inform us of any change of
address in order that we may keep you up to date of
any upgrades or improvements. Check our website.
Exclusions
Claims for any damage to either amplifiers or valves
must be reported within three days of receipt.
This amplifier is designed for normal domestic hi fi
use. It is not guaranteed for commercial or, Public
Address use, or use in other situations. The
guarantee becomes void if the unit has been
modified in any way not approved by Icon Audio.
8 Packing Instructions
It is important that the original box and packing
be used for shipping, as this provides vital
protection during transit. Please do not write on
box, but use removable labels. If returning for
service do not send the valve cover, remote control
or mains cable.
If packing the valve cover in the amplifier box ensure
that is it does not come into contact with the amplifier
paintwork as damage will result during shipping.
•Re-use the supplied plastic bag to keep the
amp clean and free from damp.
•The mains lead and remote control fits in a
foam cut-out underneath the amplifier.
•Valves should be removed, numbered and
packed in “Bubble wrap” or similar for
protection.
•If the amplifier is stored in the box, keep
upright and remove batteries from remote
control to prevent corrosion.
icon Audio (UK) Ltd
351 Aylestone Road Leicester LE2 8TA
[email protected] www.iconaudio.com
Phone [phone] [phone]
04.22 V Gen Pr 29/09/2022

Page 10
Caution: This amplifier is heavy!
Lift the amplifier out of its packing by
using the two “hand cut-outs” in the
bottom packing near the transformers.
Or you may find it easier to remove the
unit using the following procedure:
1. With the top packing in place, turn
the box “upside down” with the “flaps”
open.
2. Lift the cardboard box off.
3. Remove the bottom packing first.
4. Turn the unit the right way up and
remove the top packing.
Please be careful not to damage any
small switches and knobs on the
front and rear panel
When re-packing ensure small switches do not foul
packaging, the two hand cut-outs are normally towards
the rear of the amplifier.
Do not ship with the valve cover as damage is likely to
occur, unless you have the original packing. Or send
separately. Do not return valve cover for service.
(Please keep this information for future use).