Jeff Rowland Design Group Model 2 - Manual (Page 13)

Operation
A fter following the procedures outlined in the Installation/Rear Panel
Power Connections and Signal Connections sections, the Amplifier can be
turned on by pressing the FRONT PANEL STANDBY/POWER button. Allow
approximately twenty (20) minutes for the amplifier to reach operating
temperature and maximum performance potential. A short warm-up time is
dependent upon the amplifier being plugged in to an active AC mains
power source for at least two hours prior to activating the FRONT PANEL
STANDBY/POWER button. Therefore, it is recommended that the Amplifier
be continuously connected to an active AC mains power source.
If you desire to disconnect the AC mains for an extended period of time,
simply disconnect the AC power cable from the wall outlet and reconnect
upon your return. Slight transients may be heard in the loudspeakers during
the AC mains connect/disconnect transitions.
Your new Model 2 Amplifier will require an initial break-in period of at least
eighty (80) hours before maximum performance can be expected. Efficient
break-in procedures require the Amplifier to be fully operational (playing
music). Continuous and noticeable performance improvements will occur
during subsequent months of operation.
To achieve the maximum performance for which this Amplifier was designed,
it is recommended that balanced signal source (INPUT) and LOW INPUT
IMPEDANCE options are used. This condition requires that the driving source
component (preamplifier) is equipped with balanced outputs and sufficient
output current to properly drive the input of the Model 2 when the LOW
INPUT IMPEDANCE option is selected. Most high-quality solid state pream-
plifiers can satisfy these conditions, and best results are obtained when the
output impedance of the preamplifier (600
Ω
balanced) matches the input
impedance of the power Amplifier (600
Ω
balanced). When the impedances
are matched, maximum signal power transfer and signal fidelity are achieved
in addition to the advantage of utilization of long lengths (10 meters and
greater) of interconnect between components with no sonic degradation.
However, there will be a 6 dB decrease in volume relative to a mismatched
condition (low driving source impedance driving high load (Amplifier input)
impedance).
If there is any doubt as to the compatibility of the above mentioned
components, then HIGH INPUT IMPEDANCE should be selected. Since the
electrical performance of the Model 2 is not changed when selecting different
INPUT IMPEDANCE options, apparent differences in sonic quality can be
attributed to mismatched impedances.
Due to different sensitivities of associated equipment used with the Model 2,
the OVERALL GAIN switch can be used to optimize the total gain structure
of the entire system. This allows the volume control of your preamp to be
used in an ideal mid-range position.