Sigma ADA-21S Manual De Usuario

 

 

ADA-21 

Doc. No. – 14466 

Page 2 of 3

 

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. 
 
 
 
 
 
 
 
 
 
 

Balanced In to Balanced Out 

Balanced In to Unbalanced Out 

 

Vout = Vin 

Vout = 0.5 Vin 

 
 
 
 
 
 
 
 
 
 

Unbalanced In to Balanced Out 

Unbalanced In to Unbalanced Out 

 

(-) Input Grounded; Vout = Vin 

Vout = 0.5 Vin 

 

(-) Input Floating: Vout = 0.75 Vin 

 

The input to output level comparison provided in the figures above, assumes the outputs are terminated 

into a 600

Ω

 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 600

Ω, 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. 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

Figure 3: Front Panel Gain Adjustment 

 

+ 
C 
- 

IN OUT 

+ 
C 
- 

+ 
C 
- 

+ 
C 
- 

ADA-21 

+ 
C 
- 

IN OUT 

+ 
C 
- 

+ 
C 
- 

+ 
C 
Open 

ADA-21 

+ 
Gnd 

IN OUT 

+ 
C 
- 

+ 
C 
- 

+ 
C 
- 

ADA-21 

+ 
Gnd 

IN OUT 

+ 
C 
- 

+ 
C 
- 

+ 
C 
Open 

ADA-21 

S01 

R012 

S901 

R912