Replacing The Tubes - Edax Audio Labs MP-800 Operation Manual

REPLACING THE TUBES

The vacuum tubes become very hot once the unit has been turned on, and they should
not be touched until they have cooled to room temperature.
There are a large variety of ECC82/12AU7s available, each type has slightly
different internal structure and design.
Consequently, each type has its own sonic signature.
For the design of the MP-800 we have chosen an especial tube model, this gives to
the MP-800 its special sound characteristic.
When you need to replace the vacuum tubes use allways original EDAX tubes.
All vacuum tubes have a limited life due to reduced electron emission
from the oxide coating on the cathode and/or a buildup of impurity gases is the bulb.
Due to the hi quality of the tubes in the MP-800 the life is estimated to be
several years.
If you notice the sound quality deteriorating - higher distortion, muddiness,
or microphonic behavior - it's time to change the tubes.
Allways we recommend changing the 2 tubes at once.
If you are uncomfortable with replacing the tubes yourself, please have
It done by qualified service personnel.
1) Unplug the MP-800 and wait at least 30 minutes for the high voltage in the unit
to discharge and for the tubes to cool to room temperature.
2) Only remove the top cover by removing the two #8-32 Phillips-head screws.
It is not necesary to remove the bottom cover.
3) Note the position of the two tubes (V1-V8) in the porcelain sockets
The tubes are ECC82/12AU7
4) Remove each tube and replace with the new one.
5) Reinstall the top cover and screws.
9