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Mid
Side M-S Matrix Uses No Precision Resistors

Where we discuss new design ideas and
modern spins on old ones.

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286 posts • Page
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Mid

by
mediatechnology
» Mon May 26, 2008 1:09 am

This precision sum difference matrix for M-S mid side uses
the 0.005% matched internal resistors of the THAT1240. It encodes or decodes
depending on how you define the inputs and outputs.

Note:
Inputs must be driven from low impedance sources e.g. an op amp output. 100 nF
bypass caps not shown.

Typical crosstalk performance simultaneous
encode-decode end-to-end:

“Logic will get you from A to B. Imagination
will take you everywhere.”

mediatechnology

Posts: 1665

Joined: Sat Aug 11, 2007 2:34 pm

Location: Dallas, Texas

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
mediatechnology
» Sat Nov 15, 2008 5:49 pm

Guys - Roger has kicked around the idea of doing an M-S
board based on this trick using the 1240. What I'm thinking we would want to do
is a board which provides simultaneous encode/decode with relay bypass. Would we
also want it to be balanced I/O?

Any comments suggestions?

will take you everywhere.”

mediatechnology

Posts: 1665

Joined: Sat Aug 11, 2007 2:34 pm

Location: Dallas, Texas

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
raf
» Mon Nov 17, 2008 2:32 pm

Yes, input please!

rf

raf

Posts: 666

Joined: Sat Aug 11, 2007 4:04 pm

Location: California

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
flaheu
» Mon Nov 17, 2008 2:43 pm

Personnaly , I would be very interested, using THAT
receiver and line drivers would be a great add

flaheu

Posts: 2

Joined: Tue Aug 14, 2007 4:40 pm

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
raf
» Mon Nov 17, 2008 3:16 pm

Hi flaheu

Thanks for posting. I agree, balanced I/O
would make it universal. If a person builds it into some other device, they
could always not stuff the I/O chips.

I am wondering if we could reap
benefits from using 1200 series instead of 1240 series. I could always use the
dual footprint that I used on the MEII compressor board so a builder could use
whichever line they wanted. That is, of course, if there were real
benefits.

rf

raf

Posts: 666

Joined: Sat Aug 11, 2007 4:04 pm

Location: California

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
Gold
» Mon Nov 17, 2008 6:48 pm

raf wrote:Yes, input
please!

rf

I would like output too.
Encode/Decode with a relay bypass option sounds great.

Gold

Posts: 63

Joined: Sat Dec 01, 2007 6:20 pm

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
raf
» Mon Nov 17, 2008 8:39 pm

Ok wise guy!

You know output is extra...

raf

Posts: 666

Joined: Sat Aug 11, 2007 4:04 pm

Location: California

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
mediatechnology
» Mon Nov 17, 2008 8:47 pm

I thought the universal encoder wouldn't have an output.
That makes it truly universal.

OK, so far we have simul encode/decode, balanced I/O, relay bypass, and
InGenius (optional) balanced inputs for the I/O. (Still need to use 1240s for
the internal stages.)

Note to "self" - make sure the balanced I/O driver
has the option to preload the output in 600 ohms. This is required when SSM2142s
are used instead of THAT1646s. The SSM 2142 does not have precise unity gain
unless terminated.

“Logic will get you from A to B. Imagination
will take you everywhere.”

mediatechnology

Posts: 1665

Joined: Sat Aug 11, 2007 2:34 pm

Location: Dallas, Texas

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
emrr
» Mon Nov 17, 2008 11:25 pm

do it!

Best,

Doug
Williams
Electromagnetic Radiation Recorders

emrr

Posts: 274

Joined: Sun Mar 02, 2008 11:27 pm

Location: NC, USA

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Re:
Mid Side M-S Matrix Uses No Precision Resistors

by
Mastertone
» Thu Nov 20, 2008 10:18 am

I was thinkin about this circuit today, It would be perfect
to put in my soon to be upgraded Mastering Console, i could use a few inserts
with a M/S option, the relay idea sounds good!

Jonas Ekstrom
Mastertone

Mastertone

Posts: 11

Joined: Sat Jan 05, 2008 7:18 pm

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