Mid Side M-S Matrix Uses No Precision Resistors

[mediatechnology]

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:

[mediatechnology]

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?

[raf]

Yes, input please!

rf

[flaheu]

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

[raf]

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

[Gold]

Yes, input please!

rf

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

[raf]

Ok wise guy!

You know output is extra...

[mediatechnology]

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.

[emrr]

do it!

[Mastertone]

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!