CAUTION: Do not operate a power supply when it is not connected to a preamp.
Damage to components may result from operating the power supply with no load.
Once the interconnecting power cable(s) are securely attached (use of the locking rings is
recommended) between the power supply and the preamp(s), and the line cord is plugged
in, the power supply AC power switch may be turned on.
The pilot lamps on the power supply and the
Phono 3E
chassis indicate that the power
supply is on and the preamp is active. It takes about 30 seconds for the tubes to reach
operating temperature ready for use. During operation, is it normal for the power supply
chassis to become quite warm to the touch.
The
PSX
and
Line 2D
power supplies are protected by 20mm, 1 A, 250 V fast-acting
fuses that can be accessed by removing the fuse drawer from the AC receptacle after
disconnecting the AC line cord. Under normal conditions, it should not be necessary to
replace the fuse. If power fails to come on, you can check the fuse and replace with a
spare if necessary. A spare fuse is also located within the fuse drawer. If the fuse blows a
second time, you should not try to operate the unit. Contact Mapletree Audio Design for
information regarding service.
Input/Output Connections______
RCA jacks are provided for two stereo phono inputs, selectable using the toggle switch
located between them, and one stereo output. The same ground binding post is used for
both inputs. Left channel jacks (white) are uppermost.
Tubes____
The vacuum tubes supplied are new or new-old stock (NOS) and have been pre-tested. A
burn-in period of several hours may be needed to achieve the best sonic performance.
Tube life should be thousands of hours. Aging tubes may result in a reduced gain in one
or both channels or an increase in noise levels. Infrequently, a heater may burn out which
is indicated by total loss of sound. Replacement tubes can be obtained from several
suppliers in the U. S. and Canada.
Some listeners enjoy trying different brands and variants of tubes. The highly regarded
12SX7GT is equivalent to the 12SN7GT.
The choice of driver tubes is largely up to the owner, based on experience with the sonic
character of the brand and type variant. Lacking such direction, it is recommended that
the listener try currently manufactured tubes such as Russian and Slovakian 12AX7,
ECC83, and 5751. The 12AY7, which is a low noise version with slightly less gain, is
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