Ps 2A Power Supply Connections - Mapletree Phono 3 User Manual

possibility of ground loops forming between the two chassis, through the signal
interconnect shield and the ac line ground circuit, which can produce hum.
12SC7
12SN7 12SC7
(R)
(L)
PSX Power Supply
Power In
ON
Out Gnd Ph2 Ph1
OFF
Ch 1-2/LF Level
Power interconnect cable
AC Line cord

PS 2a Power Supply Connections______

If you purchased your Phono 3 with the Line 2B SE line preamp and are sharing a
common power supply, you will be provided with the PS 2a power supply. The PS 2a
power supply provides high voltage (B+) and heater voltage (A) for both the Line 2B and
Phono 3 preamps. It differs from the PS 2 only in providing two power output jacks. The
physical separation of amplification and power supply units eliminates induced hum
originating from power supply circuitry and components. The PS 2a provides 12 VDC
(regulated) at 1.2 A for the tube heaters and 200 VDC at 20 mA for the B+ plate voltage.
Separate 4-pin jacks are provided for the Line 2B and Phono 3 power connections via
special 4-conductor cables. Pin assignments are as follows: Pin 1: B–, Pin 2: B+, Pin 3:
A–, Pin 4: A+. In order to prevent a ground loop from forming through the common B–
connections (signal ground), the B– feed for the Phono 3 is isolated from that for the Line
2 by a series 12 Ohm resistor in the power supply. In practice, either power output jack
can be used with either preamp.
3