User Manual
14
3. Using the optical connections to provide additional inputs
In addition to the eight analogue inputs, the Clarett 8PreX has two ADAT input ports (OPTICAL IN) 
which can each provide an additional 8 audio inputs at 44.1/48 kHz sample rate, four at 88.2/96 kHz 
or two at 176.4/192 kHz. Using one or two 8-channel microphone preamplifiers equipped with ADAT 
outputs – such as a pair of Focusrite OctoPre MkIIs – provides a simple and excellent method of 
expanding the Clarett 8PreX’s input capability.
Up to 24 Mic Sources
Wordclock between 
OctoPre MKII #1
and Clarett 8PreX 
is via the ADAT link.
Optical ADAT (TOSLINK) Optical ADAT
(TOSLINK)
Wordclock
OctoPr
e MKII 
8ch Mic Amp
OctoPre MKII 
8ch Mic Amp
Inputs 1 & 2 
on front panel
Inputs 1 & 2 
on front panel
Computer running DAW
and Focusrite Control
Thunderbolt
TM
In the example, the OPTICAL OUT ports of the OctoPre MkIIs are connected to the Clarett 8PreX’s 
OPTICAL IN ports with two TOSLINK optical cables. Although mic inputs are shown in the diagram, 
this would allow any combination of up to 24 mic or line inputs, of which some could be INST level 
signals.
Stable word clock synchronisation may be achieved by setting one OctoPre MkII as the sync master 
and the Clarett 8PreX’s sync source as ADAT. The second OctoPre MkII can then be synchronised by 
connecting its WORD CLOCK IN to the WORD CLOCK OUT of the Clarett 8PreX with a BNC cable. 
NOTE: when interconnecting two digital devices by any method, always ensure that both are set to 
use the same sample rate. 
The additional inputs realised by use of the optical ports may be routed using Focusrite Control in 
exactly the same manner as the other inputs. The additional inputs can form part of any musician’s 
headphone mix, as required.










