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DACS MIDI Patchbay

Article from Music Technology, February 1989

Tense, nervous headache? Then you've probably got a patching problem in your studio. Vic Leonard looks at a cost-effective solution to MIDI-patching nightmares.

ANYONE WITH A studio setup containing more than one MIDI sound source will have encountered problems with MIDI leads. Particularly the problem of reconfiguring MIDI cables to suit a particular playing situation. And incorporating a sequencer in the studio makes things much worse. A cheap solution lies in the use of MIDI Thru boxes, but the cost of a programmable MIDI patchbay increases in proportion to its size (eight input/output being the largest under £200). MIDI Merge facilities add further to the cost. What's been needed for some time is a relatively cheap unit which can handle a large number of controllers. DACS, a British-based company, have now entered the market place with a MIDI patchbay with a difference.

The DACS MIDI patchbay is a 1U-high rack-mounted 10-channel unit. The rear panel consists of the relevant MIDI sockets while the front reveals the surprise of this piece of equipment - jack sockets. MIDI In, Thru and two MIDI Outs are provided for each channel in the form of standard ¼" jack connectors.

Circuit board and component quality is very good with no obvious skimping, except for the way in which the front panel is fastened onto the body - two out of four of the fixings on the review model had pulled away by the time I received the unit, leaving the front panel actually hanging off. Bearing in mind that this panel has the holes for fastening onto a 19" rack and that these small inserts effectively have to take the weight of the patchbay (just under 1kg), this particular design fault needs immediate attention. Also, the solder side of the printed circuit boards is completely unprotected, which could lead to shorts from other rack-mounted equipment if this unit is racked.

The instruction leaflet mentions that, as long as there are as many MIDI Ins as Outs, the power to drive the unit can be derived from the MIDI lines. The unit is active because each MIDI In has to be "decoded" by a small electronic circuit. For the sceptics, a +5V socket is provided on the rear panel and DACS will provide a power pack at a small additional cost.

The unit has the MIDI In earths connected by small jumpers with instructions to disconnect them if MIDI data is audible due to bad equipment earthing - they also advise that as few earths as possible should be disconnected. For those of you who are interested, this appears to contravene the original MIDI 1.0 specifications, which called for earth connections on MIDI Out/Thru sockets but not on those for MIDI In. Remove them all, however, and the unit ceases to function - they obviously provide the ground for the power supply from the MIDI units to the patchbay.

Equipment is connected to the bay using standard MIDI leads, while jack-to-jack leads are used for patching on the front panel. As MIDI controllers usually have two MIDI Outs and modules MIDI In and MIDI Thru (which echoes the data being received by the MIDI In socket), a "daisy chain" of MIDI connections can be easily set up. Suppose that a mother keyboard is controller 1 and is required to be patched to each of the modules 1-10. The two MIDI Outs for controller 1 could be connected to the Ins for modules one and two and the remaining sound sources could then be patched via a Thru-In chain. The manufacturers claim a delay of 0.002 milliseconds between a MIDI In and Thru, which shouldn't cause any audible problems.

So we come to normalising. In audio patchbay terms, this allows signal paths to be interrupted and re-routed by using a switch in the jack socket which is enabled when a jack plug is inserted. On this unit there are solder positions for the MIDI In, Thru and left-hand MIDI Out, allowing a favourite patching configuration to be hard wired, and only to be disconnected if a jack is plugged into the relevant front panel socket. The right-hand MIDI Out can still be used for patching without disturbing the "preset". Effectively, this gives the user one memory.

In use, patching with jack plugs is like taking a step back in time to analogue synth days. It works well as long as the connections are fairly simple but the proverbial bird's nest of cables is easy to create. Still, some people enjoy that sort of thing.

It is also rather frustrating having to perpetually re-patch the system. This is certainly the case when using system exclusive dumping, and particularly so with equipment requiring handshaking.

Anyone actually needing a 10X10 MIDI patchbay is likely to be using it in complex situations where a memory would be a Godsend - but would also add considerably to the cost. Given this limitation the DACS MIDI patchbay could take a lot of time and backache out of studio work.

Price £116.72 including VAT and p&p

More from DACS Ltd, (Contact Details).

Also featuring gear in this article

DACS MIDI Patchbay
(SOS Mar 89)

Browse category: MIDI Patchbay > DACS

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Publisher: Music Technology - Music Maker Publications (UK), Future Publishing.

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Music Technology - Feb 1989

Donated & scanned by: Mike Gorman

Gear in this article:

MIDI Patchbay > DACS > MIDI Patch Bay

Review by Vic Lennard

Previous article in this issue:

> Communique

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> Soundbits Roland 3D Editor/L...

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