Precautions at the nput.
Insert the R-plug of the (stereophonic) tonearm cable into the R- ack of the
desired phono input. Let the L-plug of the cable hang freely and isolate the
armature of this plug with the aid of a smal test glass (or similar accessoire) in
order to prevent unwated contacts. This installation avoids the critical
conductive connection between L-ground and R-ground and ensures hum-free
amplification of the monophonic signal trough the R-section of the phono
equalizer, whereas the L-section runs at idle (is not fed with signal). This wiring
scheme is also applicable and meaningfull with dual-coil mono cartridges,
although it is not obligatory for noise suppression in this case.
S NGLE-CO L MONO NSTALLAT ON
STEP 2
Precautions at the Output.
Choose an unassigned input of the line amplifier. This input, in the following for
the sake of convenient explanation denoted by SCMO (single-coil mono), is
exclusively reserved for dual-channel mono playback, aside the line input
employed for regular stereophonic phono playback denoted by STER. Install a
second pair of (ordinary stereophonic) interconnect cables IC2 (Phono
Enhancer > line amplifier), in addition to the existing cable connection IC1 used
for stereo playback as follows. Insert both plugs of IC2 into the acks of input
SCMO in the usual manner on the receiver side. On the sender side, BOTH
plugs of IC2 go into arbitrary unassigned R-channel output acks of the Phono
Enhancer (possible since the Enhancer features 3 pairs of ouput acks). This
installation obviously distributes the R-channel signal output of the phono
preamplifier over both channels of the line device (Y-connection). Select the
desired single-coil cartridge on the Phono Enhancer and then switch active
input SCMO on the line device in order to activate the dual-channel mono
playback mode. Do not forget to switch back to the line input STER before
selecting a stereophonic cartridge for playback, because:
The system reproduces the R-channel signal on both loudspeakers
(rather than a consistent stereophonic signal) when a stereophonic
cartridge has been chosen for playback on the Phono Enhancer while
input SCMO is still active on the line device!
Some phono devices with non-balanced circuit topology feature a so called
MONO SWITCH. Here the monophonic signal is distributed over the channels at
the input (hence ground loop noise is induced), processed in the initial (L and R)
amplifier stages (hence distorted twice!), MIXED together somewhere in the
middle of the circuit and then re-distributed over both channels of the
following circuitry, whereas the ground loop noise introduced to the wanted
