[sdiy] Patch Routing Idea...

[danial stocks]

>
> > And take a matrix circuit for the audio matrix (MT8816 from Mitel or
>similar)
>
>nice up to there..
>take a close look, they will allow one input to several outputs, but not
>several inputs to one output
>(or several inputs to several outputs) they also have a low ON resistance
>(<50ohms) which means you
>couldn't do the CV summing,

I had a look at the harris CD22100 4x4 matrix, and ST M8494 [I think] 12x16 
matrix.. they are both an array of analog sw's.. low on res..  you can run 
them as multi ins going to outs, or multi outs from ins, but not both at 
once.. multi outs going from 1 input is easy., multi ins going to 1 out, you 
just put input res's of a suitable value and direct to the appropriate 
o/ps.. Possibly sending the o/p ports to summin node of op amp could be the 
go, a true summing not just dodgy resistor nonsense.. I havent tried this 
out, so I dont know if doing this would cause undue level of crosstake or 
noise, b ut most likely ok for CV summing.. also note that these things 
switch quite fast, so like 4066, 4053 etc, could well put clicks in if used 
for realtime audio switching.. ok tho for changing the patch between tracks 
etc..
Cheers,
Dan

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