Avid Technology FC726, Manual

FC726 Guide

2

Basic Concepts

Channels and Banks

The FC726 can convert 56 digital audio channels in two direc-
tions simultaneously (

simultaneous bidirectional conversion

) 

with any of the supported devices. The 56 channels are di-
vided into seven banks, each with eight channels. Each bank 
may be connected to a different third-party device running at 
a different sample rate (such as Tascam DA-88 on channels 
1–8, ADAT on 9–16, and AES/EBU on 40–48).

Signal Flow

Since 56 channels can be converted bidirectionally, signal 
routing can become confusing. These simple rules should help 
clarify the signal flow: 

• Audio arriving at the MADI B Input is sent out the 

Format A Output.

• Audio arriving at the Format A connectors is sent out the 

MADI B Output. 

• The AES outputs always mirror the Format A Output.

Format A Inputs

Three connectors can be used by third-party inputs: the com-
mon DB-50 connectors, the MADI A Inputs, and the DB-25 
AES connectors. The appropriate signal is chosen according to 
the following rules: 

• If the MADI switch is ON, the MADI input is used for all 56 

channels. 

• If the MADI switch is OFF, either the common DB-50 or AES 

signals are used in eight-channel banks. 

• If only one connector is in use, that format is selected.

• If both are connected, the common DB-50 signal takes 

precedence. 

Format A Adapters

To create a compact 2U device with maximum flexibility, the 
FC726 uses a common DB-50 connector for all third-party for-
mats. An adapter is required to convert from the DB-50 con-
nector to the company’s own connector. The adapter is not 
intended to be the connecting cable; it simply adapts the com-
mon DB-50 connector so it behaves like the back panel of the 
third-party device. These adapters are available separately 
from Avid. In most cases, another cable is required to connect 
the adapter to the third-party device. See Appendix A, “Pinout 
and Cable Specifications” for detailed information. 

Sample Rate Conversion

Digital audio devices have previously been required to use the 
same sample rate to operate correctly together. The FC726 re-
moves this limitation by allowing many sample rates simulta-
neously. For example, by using the common DB-50 connec-
tors, each eight-channel bank can operate at its own sample 
rate. Furthermore, the FC726 detects different sample rates 
and automatically activates Sample Rate Conversion (SRC). 

Although the FC726 SRC is the highest quality available, some 
users may still require an unaltered, bit-for-bit copy of the 
data. In this case, connected devices can be slaved to the same 
sample clock, which disables SRC automatically (you can also 
disable SRC manually).