The SM1 is a DISCRETE Mono Summing module,
with a selectable input (on the PC board with jumpers) so you can grab
any bus and use the SM1 as the summing master for the bus, such as
Sends, Center Channel, LFE, PFL, etc.
The 8 seg LED VU meter follows the output of the final stage. The
Summing input uses the Tonelux DISCRETE op-amp for summing, then feeds
the Tonelux DISCRETE output op-amp into a transformer for the summing
(or ACA) output. The return from the ACA out comes back into a
DISCRETE booster amp, the master fader and transformer for the final
This configuration allows you to insert a
compressor after the summing amp and before the master fader (either
the front panel pot or the external fader option), then returning it
back into the fader and to the final Booster output. This modules
works the same way any typical professional recording console would
The INS (insert) button allows the engineer to compare or insert the
device such as a compressor for IN/OUT comparison or when required for
a special CUE point.
Both the ACA output and the BOOSTER output are transformer coupled.
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