TUBE REPLACEMENT
Your
model i84
amplifier’s conservative design maximizes life of the tubes. You can expect that your EL84
power tubes will last approximately 1500 hrs, while the ECC83 preamplifier tubes should last approximately
2500 hrs. Lacking the accurate time measurement, we strongly recommend replacing the output tubes at 12-
18 months interval (depending on your listening habits) and signal tubes at every other power tube
replacement (every 24-36 months). This will ensure that the amplifier always performs at its best and tube
failure will not overstress other parts.
Matched output tubes (EL84) should be used in the same channel for maximum reliability and performance.
ECC83 tubes do not need to be matched.
Before you start replacement you should make certain that the unit is turned off and disconnected from the AC
outlet and that the tubes have cooled down. Allow sufficient time, minimum 30 minutes, for tubes to cool down
and internal capacitors to discharge. Before inserting a new tube, inspect the tube for cracks and physical
damage. Make sure that the pins are straight. If you need to straighten the pins, be very careful as it may cause
the glass envelope to break, causing the tube to lose the vacuum and fail as soon as the amplifier is powered
on, possibly damaging the amplifier as well. Also, make sure to inspect the tube sockets for cracks and pin
inserts. Carefully align the pins with the socket and gently insert the new tube.
Never force a tube into a
socket.
Should you decide to buy replacement tubes from Vista Audio, rest assured that they were fully tested
before the shipment.
Only EL84 power tubes can be used. Regarding preamplifier tubes, the ECC83 tube can be replaced with
ECC81. Amplifiers sensitivity will be slightly reduced, but sonic signature of the amp will slightly change. No
other types of tubes can be used as they may cause damage to the amplifier, which is not covered by the
warranty.
We do not recommend frequent changes of the tubes, as the sockets are sensitive mechanical parts and are
rated for relatively small number of insertions.
Servicing
Because of its careful design and high manufacturing standards, your amplifier should normally require
only minimal service to maintain its high level of performance.
CAUTION: Lethal voltages are present inside the amplifier. Do not remove the amplifier’s bottom
cover and do not tamper with components inside the unit even with the power turned off. Servicing
should be left only to authorized and trained personnel.
We thank you for your confidence in Vista-Audio products. Our equipment has been
carefully assembled by highly skilled engineers and technicians. It will give you
many years of top-notch performance.
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