Advertisement
CAUTION – HEALTH & SAFETY!
When making any adjustments remember to
isolate from power supply.
Like all valve amplifiers there are hazardous
voltages inside which when switched off can take
several 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.
It is essential to install the HP8 on a stable non
slippery surface when it cannot be easily be moved by
accidental pulling of the headphone cable.
Trouble Shooting
Amplifier Dead
Check the 1amp (2amp USA) mains fuse which is in
the IEC mains socket on the rear (one fuse is a spare).
Replacements should be 20mm 1 or 2 Amp 'anti-
surge' or "T" type. These are available from Icon Audio
should you have any difficulty.
The fuse in the UK mains plug should be a 3 or 5 amp
fuse, although unlikely, this should be checked if the
amplifier fuse is OK.
No sound
Have you selected the right input? Are the connections
OK? Is everything switched on? Are the headphones
connected?
Distorted sound.
Try another source; if sound improves then it's
probably something wrong with the first source. If no
improvement
try
different
improvement could be an amplifier problem.
Background Noise
Rarely a valve may start to make intermittent "rustling"
or "crackling" noise. Almost always on one channel. If
this becomes a problem you can find out which valve
by swapping the larger 6SN7/CV181 over. If the noise
stays on the same channel it is probably the small
12AX7/ECC83. Also see "Valve replacement" and
"Bluetooth" sections.
Hum Problems
Excessive hum is generally caused problems external
to the HP8 by a poor grounding in the signal lead, or a
'hum loop' caused by having too many earths. At a
normal volume (10 o'clock) there should be almost no
hum or noise when the rear input is disconnected.
One channel missing.
Usually 'bad' connection on either the input or the
headphones. Try swapping the connection over to
establish if the cause is:
(a) Input to the amp.
channel.
(b) Amplifier or headphones. Sound will not move.
Strange noises coming from headphones
Turn volume to minimum on unused input, if problem
corrected either fault with source unit or with
connection. If noise persists, problem with amplifier.
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.
Valve Replacement
This is very easy, Switch off, disconnect from mains.
Carefully remove the bigger 6SN7/CV181 valves,
headphones,
Sound will move to the other
these should be held by the base using a "rocking
motion" when removing to prevent damage. When
replacing note the alignment of the central spigot. This
is easily broken. (These valves also have an alignment
"key" and will only fit in the valve base one way, do not
use excessive force; accidental wrong insertion would
cause damage). The ECC83/12AX7 may be removed
by gently rocking and pulling. When replacing note the
pin positions.
Do not operate without valves!
Valve life will depend upon such things as hours of use
and number of on/off cycles, As a rough guide we
would estimate maximum life of approx 4 to 10 years.
But this can vary and early failures are not unknown.
What can happen?
A valve is at the end of its life if one of the following
happens:
• The valves wear out gradually reducing the sound
quality.
• Any of the two glowing heaters could fail in any one
of the 6SN7s or the ECC83 (12AX7)
• A
valve
"microphonic" (all valves are a little microphonic).
• A valve can go noisy with rustling/crackling noise.
• The valve works intermittently.
• An air leak causes the valve to fail and the silver
"getter" material to turns white.
To maintain the sound quality we recommend the
valves be changed every 2-5 years to maintain the
full sound quality. A new set of valves will give you
back a "NEW" HP8!
if
no
Icon Audio can supply a new set of valves which
have been tested in the HP8 to assure you of the
sound quality. These range from standard to
"premium" types.
It is essential that only the correct valves are used
as some similar looking valves have a different pin
connection and insertion could result in damage to
the amplifier and risk of electric shock.
It is not good practice to remove the valves
unnecessarily as this can strain the pins and cause
micro air leaks. Icon Audio are happy to check valves
and check to performance of your amplifier, and advise
on the latest upgrades available FOC.
Service: Should you suspect a problem, you could
return the unit to your dealer or Icon Audio for a
periodic service or return the valves for testing free of
charge. You should carefully remove the valves they
should be well packed in cardboard & foam or similar,
and returned to Icon Audio. (Valves are very rugged if
packed properly).
We welcome any comments you may have regarding
errors or omissions in this manual.
Should you need further advice or information
regarding the use of this unit please contact us.
NEW OWNER?
If you have bought this unit from someone else, please
register with us by email or post stating your name,
address, model, serial number and whom you
purchased from in order that we can keep you up to
date with upgrades and improvements
could
get
"noisy"
or
excessively
Page 4
Advertisement
