Input Impedance Selection
Your amplifier is provided with user-adjustable input impedance. A four (4) position
D.I.P. switch for each channel is located and clearly marked on the back panel. Jeff
Rowland Design Group has chosen 3 values of input impedance to cover the majority of
applications. If you want to change your input impedance, please turn off the front panel
power before doing so. Selecting from the switch codes shown below will provide the
specific input impedance desired by the user.
The "low" setting is for use with most direct-coupled solid-state preamplifiers such as
those made by Jeff Rowland Design Group; the "medium" setting is for use with most
solid-state, hybrid and some tube preamplifiers; the "high" setting is for use with most
tube preamplifiers. We have provided these different settings so that you may find which
one provides the best sonic results in your system. Your amp comes set from the factory
at the "medium" (20 k ohms) adjustment.
Adjustable Gain
The overall gain structure of your Model 3 amplifier can be adjusted to one of four
different values, 20, 26, 29.5 or 32 dB. (Your amp comes set from the factory at the 26
dB adjustment.) The Model 3 can thus be used with dissimilar-gain preamplifiers, as well
as with a wide variety of analog and digital sources (since many digital sources [compact
disc players, digital to analog converters] have high output voltages relative to tuners,
tape decks, etc.). This feature allows the volume control of your preamp to be used in its
optimum position. It also permits you to tailor the gain structure for use with high or
low-efficiency speakers.
The gain switches are located on the underside of the plug-in modules and should only
be adjusted by your Jeff Rowland Design Group dealer. Incorrect installation of these
modules will result in damage to the amplifier circuitry which cannot be covered under
warranty.
