bruno2000 said:
I think that 1.5" is too narrow, thus my 71X format (2"). It allows you to stagger controls for more density (daughter board).
Just my $0.02.
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Bruno2000
Myke has already asked me to make a case for your backplane.
Our original starting point was 1.4" and 2". Ian needed 1.4" and Jim's modules were 2". With 1.5" 500 standard things were getting out of hand and we decided to stick to 1.5" and 2". In 2" we get 8 modules on a rack which fits in perfectly from a mixer point of view.
My plan was to use 44 way (2x22) card edge connector which would provide the 4 buses that Ian required. Then a separate connector below for the HT and heater. This had not been selected yet. As it required high current rating I have to give it a good thought.
The card edge connector would keep the same pin 1 position as 500 so that the rack would also accept 500 modules. For this I planned an adapter panel for stepping down from 2" to 1.5". Quite a costly thing though.
Of course with two separate pitches for 1.5" and 2" things get a bit out of hand on the backplane. So designing something similar to our current 500 series would be quite challenging. However, we definitely decided to have provision for input/output transformers on the backplane which would also take the strain from the design of the modules if the available PCB space did not permit them.
But more importantly the issue became with the rear panel. It is not possible to have the XLRs following two separate pitches. So, the options are either to have two separate, 8 and 11 slot rear panels, or to use individual, single slot width panels in 1.5" and 2" depending on the format one wants to use.
I will get back onto this and see where we end up.