MS-II Mid Side Matrix Construction Information

Construction information for DIY projects, including the MS Mid Side Matrix, Elliptic Equalizer, Mastering Console, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.
Clbraddock
Posts: 1
Joined: Mon Mar 03, 2025 8:48 pm

Re: MS-II Mid Side Matrix Construction Information

Post by Clbraddock »

This project looks awesome. Couple questions:

1. Looks like I need to separately make a +15-15 power supply. What is the approximate current draw needed? I’m assuming 1amp from 7815/7915 regulators would be more than sufficient, no? Or, is there a recommended power supply to use?

2. Is it possible to hard bypass the full circuit? I.e. route the left and right in directly to the left and right out? It looks like there is a jumper setting to do this via relay, but wanted to double check?
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mediatechnology
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Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
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Re: MS-II Mid Side Matrix Construction Information

Post by mediatechnology »

Thanks for the inquiry and joining us!
Clbraddock wrote: Mon Mar 03, 2025 9:06 pm This project looks awesome. Couple questions:

1. Looks like I need to separately make a +15-15 power supply. What is the approximate current draw needed? I’m assuming 1amp from 7815/7915 regulators would be more than sufficient, no? Or, is there a recommended power supply to use?

2. Is it possible to hard bypass the full circuit? I.e. route the left and right in directly to the left and right out? It looks like there is a jumper setting to do this via relay, but wanted to double check?
The current requirements for the bipolar supply is about 60 mA typical.
A 24V relay supply is also needed. Each relay and LED draws about 20 mA.
There is an optional on-board regulator for the relays that permits it to be powered from the +/-15 (30v) supply but most customers use a small 25W switcher.

There is no hardwire bypass on the board but there are a couple of soft bypass signal paths available. One loops the input line receiver to the output driver. The second loops across the MS insert. There simply wasn't enough room on the board to add more relays.

For galvanic full bypass most people use an insert switcher board. https://ka-electronics.com/shop/index.p ... duct_id=80
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