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6 Valve Replacement
Health & Safety; High voltages are present inside the
unit and on exposed valve sockets when valves are
removed, so take suitable care. Beware valves get
hot in operation!
Only if you feel confident should you attempt to
dismantle the CDX2 by first isolating from the mains
power by removing the plug from the back panel.
How do I know when to replace valves?
Valve life
will depend upon such things as hours of use
and number of on/off cycles. It is not good practice to
remove the valves unnecessarily as this can strain the
pins and cause tiny air leaks.
Generally speaking the ECC82/12AU7 valve should give
about 2-3 years of normal use. With heavier use this
valve should be replaced every 12 months.
Symptoms could be: Loss of volume, loss of clarity, poor
channel
balance,
distorted
sound,
excessively
“Microphonic”, intermittent noise.
Catastrophic Failure:
This could be due to heater failure, air in the valve, or a
short. Although unlikely this could happen at any time.
If the CDX2 sounds OK the valves are probably fine or
least useable.
If the solid state output is working OK or sounds better,
the tube probably needs replacing. Icon Audio will test
the valve free of charge (non UK customers should
include the cost of return postage).
7, Replacement Valves.
Use only valves marked
ECC82/12AU7. The ECC81/12AT7 may also be used.
The ECC83 will work, but not as well. So not
recommended
DO NOT USE ECC99 (heater current too high), ECC88,
6922/6DJ8/6N6 (wrong pin connections/heater ratings)
or any other valves which may be “close” as the
performance will be impaired or damage may result.
Ideally a “near perfect” match between the two halves is
needed to guarantee perfect channel balance. We
suggest that you choose from our recommended tested
valves. “Used” premium valves often give disappointing
results. We take no responsibility for valves not supplied
by Icon Audio damaging the CDX2.
Take care that you orient the valve correctly before
inserting and removing. Make sure the pins are straight,
beware excessive bending can cause air leaks.
How replace the 12AU7/ECC82 Valve
You will need a medium/large crosshead screwdriver
and a set of Allen keys (size 2mm).
1. Disconnect the power/audio connections,
remove any CD and the clamp and place the
CDX2 face down on a soft surface.
2. Remove the 3 screws that secure the right hand
side plate to the base.
3. Turn the CDX2 the correct way up and remove
the 4 socket head bolts on the RIGHT HAND
(valve window side) that secure the CD deck
door top plate.
4. Carefully remove the RIGHT HAND steel top
plate/side panel.
5. Change the valve by pulling back the retaining
spring and gently but firmly pulling the 12AU7
valve out. A small amount of rocking motion may
help.
6. Insert new valve and replace spring, making
sure the pins are clean.
7. TO RE-ASSEMBLE first fit the side plate and
insert the 3 bolts from the underside. Do not
tighten at this stage.
8. Re-fit the deck door top plate and secure with
the 8 Allen head bolts.
9. Tighten the all the bolts.
10. Test CD player output working OK.
