Pioneer SA 9100 Owners Manual

Page 2

FEATURES

The Preamplifier Section

Phono Equalizer With Differential Amplification
Circuit

No cost or effort has been spared to provide the most exact
and stable phono equalization of any stereo amplifier we
know. The equalizer unit, sealed in a special case to shield
it from leakage and hum, uses a total of it) transistors.
Its front end is a differential amplifier circuit providing
stable operation bias and unvarying performance after long-
term use. The equalizer output is a single ended push-pull
(SEPP) design. Although the phone inputs are very sensitive,
they can, on the other hand, handle input signals up to
ZSOmV without causing overload, so that practically any
dynamic phono cartridge can be accommodated. Specially
selected - and quite expensive e parts are employed
throughout: low-noise nichrome processed metal-film
resistors (sputtering process) with a tolerance of 11%,
styrol capacitors of 12% tolerance as found in laboratory
gear. Balanced (+) and (~) power is supplied to the equa-
lizer, resulting in sup'rior dynamic range and stability, and
special steps have been taken to prevent click noises. With
these features, the equalizer stays within 10.2dB of the
RIAA phono equalization curve.

Accurate, Versatile Twin Tone Controls With Four
Working Frequencies

The tone control circuits are active NFB types sealed in
a special case, Two bass controls (working points at 50
and lOOHz) and two treble controls (lOkHz and 20kHz) are
provided, permitting practically any desired frequency
contour to be obtained. The control knobs have click-
stops, each increment representing 2dB change. A tone con-
trol defeat switch lets the signal bypass the tone controls,
giving absolutely flat response as required for measurements
etc. Parts used in the tone control circuits are of the same
narrow tolerances as in the equalizer.

Additional Electronic Protection Circuit

Speakers and output transistors are further protected by
an electronic circuit that shuts off the power at the first
sign of trouble such as a short-circuit in the speaker leads.
A pilot lamp on the front panel lights when this protection
circuit has been activated.

Generous Power Supply Unit, Wide Power
Bandwidth

The ripple filters in the power supply units have a large
capacitance of 1,5,000 uF in each of (+) and (-) sides.
Power bandwidth ranges from 20 to 20,000Hz, meaning
that full power is available at any point of the audible
frequency spectrum.

Preset Level Controls For Phone 2, Aux 2,
Speakers B

For comparative listening tests, and for balancing the
volume levels of different program sources, three preset
level controls are provided on the rear panel.

Constant-Current Circuits Solve Vital Problem Of
All Transistor Amplifiers

In the past, all transistor amplifiers were afflicted by shift-
ing of transistor working points in accordance with chang-
ing input signal levels. This could lead to instabilities and
crossover distortions when the signal level moved out of the
transistors range of linearity. In a radical breakthrough.
Pioneer has solved this problem, employing constant-current
circuits at two stages to keep transistor operation stable
regardless of signal level.

Presetting of Volume Range

Where the full maximum volume is never needed - with
speakers of insufficient power handling ability, for example
7 the maximum volume level can be pre-set at ~15dB or
>30dB. The volume control knob then covers the reduced
range, permitting finer adjustments.

Active High And Low Filters With Selectable Cut-
Off Frequencies

Active circuits with a cutoff steepness of lZdB/octave
have been provided as high and low filters, Their cutvoff
frequencies can be selected to permit noise reduction only
in the desired range: below 8H1 (subsonic) or 30Hz for the
low filter, above 8kHz or i2kHz for the high filter.

Provisions For Two Tape Decks, Tape Duplicating,
Three Pairs Of Speakers

Two tape decks can be connected for recording, playback,
and tapeto-tape duplicating in either direction, Up to three
pairs of speakers can be driven individually or A+B, A+C.

Elegant Styling Matches Technical Excellence

The functional layout of the control panel is as practical
as it is beautiful. The natural walnut cabinet provides pro-
tection and adds decorator looks. Combination with other
Pioneer hi-fi components will result in a music system of
well-matched beauty in sound and appearance.