Furman SP-20A Quick Manual

STEREO POWER AMPLIFIER

FEATURES

20 watts per channel in stereo mode
Toroidal transformer for ultra-quiet performance
May be bridged for 40 watt mono operation
(requires load of 8 or more ohms)
Front panel headphone jack with volume control
Ideal for small speakers or headphone system
Speaker on-off switch
Overload and signal-present LED's for each channel
Power-on indicator
Ground lift switch
Provision for remotely located headphone volume controls

DESCRIPTION

The SP-20A Stereo Power Amplifier is a unique and
economical 20 watt per channel stereo amplifier. Its toroidal
transformer delivers ultra-quiet performance, making it ideal for
recording studio applications. The SP-20A may be operated in
any of three modes as selected by a rear-panel switch: normal
stereo, two channel mono, or single channel (bridged) mono.
The latter mode allows a power output of 40 watts provided the
load is 8 or more ohms.
The SP-20A is housed in a compact, half rack chassis,
allowing it to be mounted either alone or side by side with other
SP-20A's in a 19" rack. Mounting kits are available from
Furman.
The SP-20A's small size makes it ideal for modular use in
large commercial installations with multiple small speakers. Its
power capacity is also just right for driving the small "cube"
reference speakers used in most recording studios as a
comparison with the main control room monitors — it can
power them without overpowering them.
The SP-20A's output is available through either of two
connectors: standard banana jack binding posts for speakers,
Furman Sound, Inc. 1997 South McDowell Blvd. Petaluma, CA 94954 USA
Phone: (707) 763-1010 Fax: (707) 763-1310 Web: http://www.furmansound.com
®
or through a male XLR connector. The latter allows the unit to
become a headphone driver, linking any number of Furman HR-2
Headphone Remote Stations together via standard microphone
cables. Each HR-2 station conveniently clips to a mic stand and
provides individual volume controls for two sets of headphones.
When used for overdubbing or rehearsal, this setup provides
plenty of loudness in any kind of headphones (even older low-
impedance models), and allows each musician to set his or her
own comfortable volume level. When the overdubbing is complete
and the musicians remove their headphones, the SP-20A can also
power the tape playback speakers through the banana jacks. The
output — headphone chain or speakers — is selected by pressing
a front panel pushbutton. An additional headset may be plugged
directly into the SP-20A's front panel. A volume control is provided
for it.
The SP-20A has a convenient input level control on the left
side of the front panel. A pair of yellow LED's — one for each
channel — light up whenever signal is present (threshold -28
dBu). Another pair of red LED's show an overload condition in
either channel. The SP-20A is fully protected against thermal
overload, and it can withstand a short circuit on any or all outputs
for an indefinite time without damage.

OPTIONS

Model SP-20AB: Provides balanced inputs with XLR
connectors in place of 1 / " phone inputs.
4
Rack Mounting Kits: Adaptor kits for mounting one SP-20A
centered in a 19" rack (HRKIT-1), or two SP-20A's side by
side in a 19" rack (HRKIT-2).
Accessory: Model HR-2 Headphone Remote Station: An
inexpensive, compact, unobtrusive box that attaches to a
mike stand or belt, providing two headphone jacks, each
with its own volume control. Any number of HR-2 stations
may be daisy-chained to an SP-20A using standard
microphone cables. Comes with snap-on, snap-off mike
stand clamp. (See picture on other side.)
MODEL SP-20A