Mapletree Ultra 4C, PS 2D User Manual
Mapletree Audio Design
Ultra 4C Preamplifier
Ultra 4C Stereo Phono/Line Preamplifier
PS 2D Power Supply
User’s Manual
Rev. Mar. 22, 2019
Mapletree Audio Design
R. R. 1, Seeley's Bay, Ontario, Canada, K0H 2N0
(613) 387-3830
www.mapletreeaudio.com
info@mapletreeaudio.com
© Copyright Lloyd Peppard 2002-2019 -Specifications subject to change without notice-
Introduction _
2
The Mapletree Audio Design Ultra 4C Stereo Phono/Line Preamplifier offers the
audiophile a number of desirable features:
Exclusive use of NOS octal tubes, known for low distortion and musicality.
Switchable for use with 12SN7GT or 6SN7GTB tubes.
Precise RIAA equalization (±0.5 dB) using non-interacting passive and active filters.
High input impedance and low output impedance.
Parallel output jacks for bi-amp or headphone amplifier applications.
Home Theater (HT) mode switch on front panel that bypasses the preamp circuitry
and connects the selected line input directly to the output jacks.
Enhanced connectivity with 3 line inputs, phono input, and 2 line outputs.
Phono gain of 48 dB suitable for all moving magnet (MM) and high-output moving
coil (MC) phono cartridges.
Audio grade polypropylene and polystyrene film capacitors in signal path.
Power Supply Connections______
3
Power
ON
The Mapletree Audio Design PS 2D power supply provides +12 VDC (regulated) heater
supply voltage and +200 VDC B+ plate supply voltage at a current of 15 mA (see
specifications). It utilizes low-noise ultra high-speed diodes to achieve low noise with the
high efficiency of the bridge rectifier topology.
The separate power supply eliminates induced hum originating from power supply
circuitry and components. The power connections to the preamplifier chassis are made
through a special 3-conductor power cord that plugs into jacks located on the rear panels
of the power supply and preamplifier chassis.
CAUTION: Do not operate the power supply when it is not connected to the
preamp. Damage of components may result.
Once the interconnecting power cord is securely attached between the two chassis and the
line cord is plugged in, the power supply can be turned on. The pilot lamp on the power
supply chassis indicates that the unit is on. 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 warm to the touch.
The power supply is protected by a 20mm, 1 A/250 V fast-acting fuse, which can be
accessed by removing the fuse drawer from the ac inlet receptacle after the unit has been
unplugged for at least 60 sec. 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 if
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