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Typing error.

Which way should the diodes be wired across the regulators?

ben adrian

Thanks so much Greg, I know it's not like you don't have anything else to do.
And thanks for the link cstof. I hadn't run across that site in my searches.

what are the 2 10k pots and additional 5 50k pots? Are they internal trimmers? If so, how are they set? I see 4 pots on the front panel of your finished product. That leaves 5 pots unaccounted for.

the 50k 's are offset voltage trimmers used to null the inherent imbablance in the opamps. they would be internal trimmers.
the 2 10k pots look like gain trims on the input amps and are probably the two knobless pots you see on the front panel.

Me, I'm leaning towards building a dual matrix with an insert - one passive/transformer and one active - to fuck with non-M/S stereo signals as well. I'll try to let you know how it goes and I'm sure ask questions when it dosen't work.

Cheers,
Tim

Tim,

Thanks for the info. How do you suppose one would go about balancing the varied opamps? Just monitor with a VOM and adjust the trim pots until the levels match?

Dan

Dan,

It's actualy just a DC offset - without compensation the output can float to the supply voltage. With no input, adjust for 0VDC at the output and you're golden.
I'm only talking out of half-my ass here, solid state electronics isn't my strongest area but I gots me some schooling that tends to make me act like i know what im talking about.

tim

The unit in the picture is a 2 channel (2 sets of m-s decoders) one. The pots on the face plate are the 50K "mid" and "side" gain pots for both channels.
The 10k trim pots are to calibrate the channels to have the same input level (going to the main gain pots).
Eventually I'm going to tear out the second decoder since we don't us it that much, and use those pot holes for an output L-R trim.
Thanks guys for filling in on the offset info while I was gone.
Forums are handy aren't they?

Nadege wrote:Hi, Greg I was wondering why I can't see the MS matrix schematics, did you removed it.

I totally understand the MS decoding process electronically, electricaly and decoding a MS signal is pretty easy for me. But I'm totaly lost about the way to encode a stereo source into a MS format.... Could you give me some explaination?? I can't manage to find anything about this over the net.


Thanks for your help

I can answer that:

We're in the process of moving the server. Some of the files and pictures that were stored on the old server have not yet moved to the new one. They will available in the near future.

Hope that helps.

Nadege wrote:I totally understand the MS decoding process electronically, electricaly and decoding a MS signal is pretty easy for me. But I'm totaly lost about the way to encode a stereo source into a MS format.... Could you give me some explaination?? I can't manage to find anything about this over the net.
Thanks for your help

Encoding in this case is just making a sum (L+R) and difference (L-R or L+R with its polarity reversed) of the stereo source. You can do this with our MS box by feeding it a stereo signal. This then can be decoded back to stereo using another one of our boxes.
That will be $2000 please.

For those of you who are interested in reading about Mid-Side recording, you might be interested in reading this monograph from the BBC.

Sadly, we don't publish papers like these any more...

http://www.bbc.co.uk/rd/pubs/archive/pd ... aph_38.pdf

Really Rodabod, where on Gods earth did you find that article? Are there more? I've always had a lot of respect for the BBCs engineering department and would love to get my mitts on more of their wise words!