D21m System

6.2

Analog I/O Cards

6.2.1

Mic/Line In Card (,,)

A949.0427		 Four analog microphone/line inputs, electronically balanced, with 24 bit,
44.1/48/88.2/96 kHz delta-sigma A/D converters. Four analog split outputs,
electronically balanced. Green ‘signal present’ and yellow ‘phantom power’indicators per channel. Mic/line sensitivity, gain setting in 1 dB steps, lowcut filter, soft clipping and 48 V phantom power on/off are controlled by theconsole software. Inputs and split outputs on a standard 25-pin D-type connector (female).		
Gain setting: 15 dBu 0 dBFS, unless otherwise noted.
–60…+26 dBu		 Input sensitivity (for 0 dBFS)		
Input impedance
1.8 kΩ
		
Split out gain (input sensitivity –60…+3 dBu)
0 dB			
(input sensitivity +4…+26 dBu)
–20 dB		
Split out impedance
50 Ω		
Equivalent input noise (Ri 200 Ω, max. gain)–124 dBu		
Crosstalk (1 kHz)
< –110 dB		Frequency response (30 Hz-20 kHz)
–0.2 dB		
THD&N (1 kHz, –1 dBFS)< –97 dBFS			
(20 Hz-20 kHz, –30 dBFS)< –111 dBFS		CMRR (30 Hz-20 kHz, all gain settings)> 55 dB			
(1 kHz, input sensitivity –10 to +26 dBu for 0 dBFS) typ. 100 dB		
Low-cut filter
75 Hz / 12 dB/oct.		
Input delay (local)
38 samples (0.79 ms @ 48 kHz)			
(remote)45 samples (0.94 ms @ 48 kHz)		
Current consumption (7 V)
0.2 A			
(±15 V)
0.25 A		
Operating temperature
0-40 °C
Insert Connector

Sensitivity–60...+26 dBu
Mic/Line In 1
Split out 1

AINS

0 dB*
–20 dB*

Mic/Line In 2

INS0 dB*

Split out 2

DMic/Line In 3
Split out 3

AINS0 dB*

Backplane Connector–20 dB*–20 dB*

Mic/Line In 4INS0 dB*

Split out 4D–20 dB*

48 V Phantom Pwr

Sensitivity Control
Control Logic

High-Pass Filter

Insert Control* 0 dB for input sensitivity –60...+3 dBu, –20 dB for input sensitivity +4...+26 dBu

26

Document generated: 04.03.15

D21m System

RA1
RA2
RA3
RA4
RA1...4: Factory Setting (Level Fine-Adjustment)

LEDs

PHANTOM 1-4
SIGNAL 1-4

For each channel a yellow LED indicates that pantom power is on.
For each channel a green LED indicates whether input signal is present; its
brightness is a rough indication of the signal level.

RA1-4

Please note that the level fine-adjust trimmer potentiometers are factory-set.
They need to be adjusted only after having repaired the card.
Select 15 dBu input sensitivity. Feed an analog signal with a level of +6 dBu to
one of the analog inputs. Measure the digital output level either on the MADI
output or, after routing through the core, on one of the AES/EBU outputs.
Adjust the level with the corresponding trimmer potentiometer to –9 dBFS.

Alignment		Connector Pin Assignment		
4× BALANCED MIC IN/SPLIT OUT (25pin D-type, fem., UNC 4-40 thread)2513

Solder/Crimp View
(or Socket View)

141Important!		

Document generated: 04.03.15

Pin12345678910111213Signal
CH 4 split out +CH 4 split out GND
CH 3 split out –CH 2 split out +CH 2 split out GND
CH 1 split out –CH 4 in +CH 4 in GND
CH 3 in –CH 2 in +CH 2 in GND
CH 1 in –n.c.

Pin141516171819202122232425Signal
CH 4 split out –CH 3 split out +CH 3 split out GND
CH 2 split out –CH 1 split out +CH 1 split out GND
CH 4 in –CH 3 in +CH 3 in GND
CH 2 in –CH 1 in +CH 1 in GND

If wired correctly, the microphones are isolated from the D21m chassis. Thecircuit within the microphone takes its supply from pins 2 and 3 (+ and –) forthe positive, and from pin 1 (GND) for the negative reference. If a patch bay
is implemented, GND (pin 1 on XLR connector) of each microphone input
must be connected to its corresponding GND pin, but not to the chassis. Ifthe chassis is used as negative reference for a microphone instead of GND,
the GND net of the D21m is pulled towards –48 V. This causes the HD linkreceivers not to work correctly or to be damaged, depending on the type andthe number of microphones connected.
As a workaround, GND and chassis may be connected within the D21m frame.
If currents flow between the chassis nets of multiple devices, the analog signals can be degraded in quality (e.g. perceivable as hum).
27