Mid Side M-S Matrix Construction Information

Construction information for DIY projects, including the MS Mid Side Matrix, Width Controller, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.
fuccimain
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Re: Mid Side M-S Matrix Construction Informatio

Post by fuccimain » Wed Jan 22, 2014 2:03 pm

, oh, yeah I was originally calculating for 10nf, as I was using the example on the page where the circuit came from. .. So I had it right for 10nf

fuccimain
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Re: Mid Side M-S Matrix Construction Information

Post by fuccimain » Wed Jan 22, 2014 2:07 pm

Sorry I saw my typo from where you,quoted me, I had written 10uf. My bad

fuccimain
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Re: Mid Side M-S Matrix Construction Information

Post by fuccimain » Wed Jan 22, 2014 2:45 pm

Ideally I'd like to be able to go from 20hz to say 100hz, instead of down to 3.4hz.

With the added 100k bias resistor, I'm having a bit of trouble working out the circuit. If I'm going to be bypassing the HPF, I should take the bypass before the .47uf cap?, , or figure out a resistor value that equals a hpf cutoff at a decade above 20khz (200,000khz), but in series with the 100k bias resistor, to keep it in the circuit at all times. I guess I'm a bit lost on how to accomplish this.

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mediatechnology
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Relay Bypass Board

Post by mediatechnology » Mon Aug 11, 2014 1:40 pm

An MS board customer made me aware of this general-purpose relay board ideal for use with the MS matrix as a bypass, mute or solo switcher:

http://www.ebay.com/itm/Four-DPDT-Signa ... 1243522520

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Relay Bypass Board eBay
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emrr
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Re: Mid Side M-S Matrix Construction Information

Post by emrr » Tue Aug 12, 2014 10:18 am

That saves a bit of work.
Best,

Doug Williams
Electromagnetic Radiation Recorders

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mediatechnology
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Velleman K8090 USB and Pushbutton-controlled Relay Board

Post by mediatechnology » Tue Aug 12, 2014 10:51 am

Thanks Doug.
Velleman also make the K8090 8 Relay Board that has USB and pushbutton control.

As I understand it the buttons can be programmed via USB to operate in banks using software-defined logic.
Then the USB can be disconnected if needed.
Thus, a "solo" pushbutton command for instance could operate mute functions on the other un-solo'd channels.
I've never tested it but have been thinking about getting one of these boards as well.

Product page: http://www.vellemanusa.com/products/vie ... &id=525191
pdf of Assembly manual: http://www.vellemanusa.com/downloads/0/ ... _k8090.pdf
Forum post: http://forum.velleman.eu/viewtopic.php?f=5&t=4153
You Tube Video of the software: https://www.youtube.com/watch?v=Eej1kU98QlI
MCM, Amazon and a lot of people stock these: http://www.mcmelectronics.com/product/V ... 0-/80-7805

My only reservation on any of these boards is that they do not necessarily use sealed relays but one could easily buy extra Panasonic DS2Y-series and build the boards with the better parts.
The Velleman only provides the N.O. contacts but the N.C. ones could be brought out directly to the circuit with flying wires.
The N.O. contacts do have MOVs across them which shouldn't be stuffed.

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Velleman K8090 USB and Pushbutton-Controlled Relay Board
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simon
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Re: Mid Side M-S Matrix Construction Information

Post by simon » Fri May 15, 2015 8:54 pm

hello, I have few question about the MS circuit :

1. Why not use 1246 instead 1240 for U10 and U11, so we don't have to use the -6db inverting stage ?
2. If I want to put -6db attenuation at the encoder, can I use 1246 for U3 and U4?

regards,

simon

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mediatechnology
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Re: Mid Side M-S Matrix Construction Information

Post by mediatechnology » Tue May 19, 2015 8:12 am

1. Why not use 1246 instead 1240 for U10 and U11, so we don't have to use the -6db inverting stage ?
2. If I want to put -6db attenuation at the encoder, can I use 1246 for U3 and U4?
Thank you for joining us simon.

That's an easy one to answer.

A THAT1246 cannot be used because U3 and U10 cannot perform L+R (U3) or M+S (U10) summation with equal weightings at pins 1 and 3 when a THAT1246 is used.
A THAT1240 has equal (matched) value resistors in series with pins 1 and 3.
A THAT1246 does not: There is a 2:1 ratio of resistor values.

Though one could alter the weighting of Side by adding gain in series with pin 1 of U3 to use a 1246 that has its own set of issues.
The phase shift of that gain stage would totally blow HF crosstalk.
Symmetry is very important.
If you stare at U3/U4 and U10/U11 there's a lot of symmetry inside those op amp-looking triangles.

If you are concerned about encode level build-up in mid, make the decoder with it's -6dB stage the encoder and vice-versa.
Other than the input/output labels and the -6dB gain stage the encoder and decoder are functionally identical.
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tron888
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Re: Mid Side M-S Matrix Construction Information

Post by tron888 » Sat May 14, 2016 12:57 pm

heyyy!! i just got this board!! super excited for it to arrive and start smoking.
so i got a couple questions....
i am thinking of 18v DC supply from EXPAT (uber power supply) would that work for this build?

also, i would like to have mute and bypass switch on the box . i see these on ebay still going, but its 12VDC board, is there an easy way to fit all ??
... also, i got probably lying around a few of igor`s bypass boards i have been using for GSSL builds. maybe those can work? but i think theyre also 12vDC

anyways, just before anything, sorry im total noob but i work hard and read a lot the forum!

thanks a lot for your help!

Patricio

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mediatechnology
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Re: Mid Side M-S Matrix Construction Information

Post by mediatechnology » Sat May 14, 2016 6:40 pm

Patricio - Thanks for joining us!

Wow, you got that board quick.

+/-18V supplies work great and are preferred due to it's greater headroom in the Mid channel.

The bypass boards I now have from Markus are just the ticket.
The two insert board with flip (optional) is ideal for the MS inserts.
To bypass the whole MS board in the Left/Right domain you can use the same insert board wired with only four relays for a single insert.

The Build thread is here: viewtopic.php?f=7&t=797
And the boards are here: https://www.etsy.com/listing/275593012/ ... tering-two
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