Sigma Audio Configurations, Front Panel, ADA-21S STEREO AUDIO DISTRIBUTION AMPLIFIER

ADA-21S STEREO AUDIO DISTRIBUTION AMPLIFIER

AUDIO CONFIGURATIONS:

The source and destination audio equipment must be evaluated to determine if they are Balanced or Unbalanced. After determination is made, refer to the drawings provided to select the proper audio configuration. The outputs can be any combination of balanced or unbalanced.

			ADA-21
		+
+			+	+
C		C	C	C
-	-		-	-

IN OUT

Balanced In to Balanced Out

Vout = Vin

		ADA-21
+	+	+	+
Gnd	C	C	C
	-	-	-

IN OUT

Unbalanced In to Balanced Out (-) Input Grounded; Vout = Vin

(-) Input Floating: Vout = 0.75 Vin

		ADA-21
	+		+
+		+
C	C	C	C
-	-	-	Open

IN OUT

Balanced In to Unbalanced Out

Vout = 0.5 Vin

			ADA-21
+	+		+	+
Gnd		C	C	C
	-		-	Open

IN OUT

Unbalanced In to Unbalanced Out Vout = 0.5 Vin

The input to output level comparison provided in the figures above, assumes the outputs are terminated into a 600Ω load.

FRONT PANEL:

The adjustments and indicators on the front panel (Figure 3) can be accessed through the slots provided in the frame in which the ADA-21S is installed. When mounted within the SS-2100 Series frames, it will be necessary to remove the front panel of the frame to gain access to these items. Factory settings of the module provide unity gain when terminated in 600Ω, and a bandwidth of 30 KHz.

Gain control for the right channel is achieved by adjustments to S01and R012. Gain control for the left channel is achieved by adjustments to S901and R912. S01 and S901 provide gain adjustment in increments of 6dB, while R012 and R912 provide fine adjustments of +/- 3dB. The positions of S01 make the following adjustments to the gain level of the circuit - = OFF, 1= -6dB, 2= 0dB, 3= +6dB, 4= +12dB, 5= +18dBand 6= +24dB.

	1 2 3	4 56		1 2 3	4 56
R912	S901		R012	S01

Figure 3: Front Panel Gain Adjustment

ADA-21

Doc. No. – 14466 Page 2 of 3