Samson Audio Servo 4120 Brochure

• Rack-mount quad power amplifier (2-space).

• 120 watts per channel into 4 ohms (quad).

• 240 watts into 8 ohms (mono bridge per pair).

• 20 Hz to 50 kHz frequency response.

• Balanced 1/4

″ and unbalanced RCA inputs.

• Binding post outputs.

• Turn-on muting to prevent speaker “thumps.”

• Smart servo circuitry protection against overheating

and overcurrent.

• High-current output power transistors.

• Unique bipolar circuit design continuously keeps DC

output during idling at or near 0 V (thus keeping idle
speakers at their 0 point).

• Two front-panel protection LEDs, with LED indicators.

• Four independent volume controls with LED meters.

• New UL standard insulated caps and protective cover

over output connectors.

• Convection cooled (No Fan).

• All-steel chassis with lightweight anodized aluminum

heat sink.

• 3-Year warranty.

12 12

SERVO 4120

AMPLIFIER

POWER

The Servo 4120 power amplifier is designed for use
in recording studios, live performance, distributed sound
and other permanent installations. This 2-space rack­mount quad power amplifier delivers 120 watts per chan­nel into a 4 ohm load (in mono bridge mode, 240 watts
into 8 ohms per pair), over a bandwidth of 20 Hz to 50
kHz. The four 120 watt amplifiers can be bridged sepa­rately to provide two 240 watt amps or one 240 watt
amp and two 120 watt amps. The 4120 features high-cur­rent output power transistors and a unique bipolar cir­cuit design that continuously keeps DC output during
idling at or near 0 volts. It also includes balanced 1/4

″

and RCA inputs and binding post outputs, 2 front-panel
protection LEDs, four separate volume controls with LED
indicators and thermal and overcurrent protection circuit­ry. The amp is also equipped with special insulated caps
and a protective covering ov er the output connectors con­sistent with the new UL standard. The Servo 4120 is con­vection cooled for silent operation, without f an noise or
need for filter maintenance.

Contact:

Samson Technologies Corp., P.O. Box 9031, Syosset, NY 11791-9031 • Phone: [phone] • Fax: [phone] • www.samsontech.com

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

!

USE CLASS 2 WIRING

AVIS;

RISQUE DE CHOC ELECTRIQUE

NE PAS OUVRIR

DO NOT EXPOSE THIS EQUIPMENT

TO RAIN OR MOISTURE.

emc

EUR . USA . JPN

BRIDGE

OFF ON

CH4 R

CH3 R

CH4

CH3

4Ω 120W

MAX. LOAD

-++-

CH2 L

CH1 L

-++-

BRIDGE

OFF ON

SAMSON

SERIAL NUMBER

SERVO 4120

QUAD AMPLIFIER

SAMSON TECHNOLOGIES CORP., U.S.A.

AC

INLET

USA & CANADA 115V - 60Hz

EUROPE & UK 230V - 50Hz

650W MAX.

CAUTION:

DISCONNECT SUPPLY CORD
BEFORE CHANGING FUSE.
FOR CONTINUED PROTECTION
AGAINST RISK OF FIRE, REPLACE
ONLY WITH SAME TYPE OF FUSE.

ATTENTION:

DEBRANCHER AVANT DE
REMPLACER LE FUSIBLE.
UTILISERUN FUSIBLE DE
RECHANGE DE MEM TYPE.

USA & CANADA
T 8A/125V (115V)
EUROPE AND UK

T 6.3A/250V (230V)

FUSE

-+

+-

MONO 8Ω

-

+

CH2

CH1

4Ω 120W

MAX. LOAD

-+

+-

MONO 8Ω

-

+

The power amplifier, being of four channels, shall
deliver a minimum of 120 watts into loads of 4 ohms, or
240 watts into loads of 8 ohms when in the bridged
mode, or 240 watts + 120 watts + 120 watts (one side
bridged). It shall be passively cooled, and shall have inter­nal short-circuit and thermal protection circuitry. A pro­tection LED indicator shall activate and the power amplifi­er shall disconnect the amp loads to protect against short
circuits, overheating, severe overcurrent conditions or DC
offset present at the outputs. The power amplifier shall
have slow start-up and muted inputs on turn-on. Inputs
shall be on 1/4

″ TRS balanced phone connectors and
unbalanced RCA gold-plated connectors. Outputs shall be
on insulated binding post connectors.The front panel
shall have 4 independent level controls, each with a level
indicator, a master power switch and amplifier protection
LED.

The power amplifier shall have a frequency response
of less than 10 Hz to 88 kHz (-3 dB), signal-to-noise equal
to or greater than 103 dB and THD less than 0.07%. Total
power consumed at full audio power shall be 820 W (120
Vac/60 Hz) and 850 W (220 Vac/50 Hz)). The dimensions
shall allow for standard 19" EIA rack mounting or 17.5

″

(444 mm) wide without rack ears. It shall be 3.25″ (82.5
mm; 2 rack spaces) high and 10.75

″ (273 mm) deep.
Weight shall be 29.5 lb. (13.4 kg). The power amplifier
shall carr y a three-year warranty.

The Power amp shall be SAMSON SERVO 4120.

Output Power (typical all channels driven):

4 Ω, 1 kHz, 1% THD, 86 W

4 Ω, 1 kHz, .0072% THD, 60 W

8 Ω, 1 kHz, 1% THD, 57 W

8 Ω, 1 kHz, .0046% THD, 47 W

8 Ω bridged, 1 kHz, 1% THD, 171 W

8 Ω bridged, 1 kHz, < .013% THD, 142 W
Frequency Response (-3 dB): <10 Hz to 85 kHz
Frequency Response (1 watt): 20 Hz to 20 kHz, -0/-.2
Crosstalk (adj. channels): -82 dB, 1 kHz @ rated output
Distortion (THD+N, 20 Hz to 20 kHz) (80 kHz LPF):
at rated power: < .08%
at 1 watt: < .05%
Sensitivity (level control at maximum): +4 dBu
Damping Factor (8 Ω): > 180
Dynamic Range: 80 dB below rated output

(20 Hz to 22 kHz B.P.F.)
Input Impedance: >10 k Ω balanced/> 10 k Ω unbalanced
Power Consumption: 360 W @ 120 V/60 Hz

395 W @ 220 V/50 Hz

Dimensions: 17.5” (w) x 3.25” (h) x 10.75” (d)

444 mm (w) x 82.5 mm (h) x 273 mm (d)

Weight: 25 lb / 11.3 kg

ARCHITECT’S AND ENGINEER’S

SPECIFICATION

SERVO 4120 SPECIFICATIONS

FREQUENCY RESPONSE

Specifications subject to change without notice. ©1998 Samson

AUDIO PRECISION servo 4060/4120 THD +N (%) & LEVEL (W) vs FREQ (Hz)

0dB ref THD

5.0000

4.0000

3.0000

2.0000

1.0000

0.0

-1.000

-2.000

-3.000

-4.000

-5.000

10

100

1k

10k

Ap

50k

1.000
.9000
.8000
.7000
.6000

.5000
.4000
.3000
.2000
.1000

0.0