Plugs, sockets, and cables

MIDIfication
1

I am just getting started with construction.  However, it immediately strikes me that the single row pin headers used on the various boards may be less than ideal in the environment of a midified organ console.  They aren’t very robust, you wind up with a lot of connectors, and you can’t make cables with IDCs.

I am looking at the possibility of laying out the DIN board to bring all the inputs to a single 2x20 0.100 pin header which could be shrouded.  This would allow the use of a single ribbon cable connector for 32 inputs.  On the console side you could use the same connectors or 37 pin D or 50 pin telco, all available as IDC connectors.  The board might be slightly harder to construct by having a few more jumpers and by having the pull-up resistors a bit less regular.

There are two problems I see in using a single input connector.

The bit order WILL be scrambled.  The scramble could either be in the order of the data received or in the order of the inputs on the connector.  

It is hard to fill the unused inputs randomly.  If you use 2 32 input connectors for a keyboard, the 3 extra inputs aren’t easy to take elsewhere.

Any other thoughts on this?

Jim Henry

2

You mention that ‘you can’t make cables with IDC’s’.  This isn’t necessarily true.  In

my console the drawknowbs have 5 pins on the back spaced 0.2 inches apart.  A

single 20 conductor  ribbon cable connects to four drawknobs.  There are four

10x2 IDCs crimped onto the cable.  By staggering how they are placed onto

the drawknob pins all 20 conductors in the cable are used.   It’s not pretty but it

works.  I haven’t looked at  trying this technique with the DINX4 module.  In any

event the outputs are scrambled and the cables need to be labelled as to position.

If I were going to go to the trouble of laying out a  new circuit card I would try very

hard to either have the outputs in order on the connector or do it in software.

It’s much easier to wire stuff when you can just use pin numbers to trace things down.

At least in my experience.

3

I am following your dialog concerning connectors and cables.  Is there a connector that fits the single row pins on the core card that also attaches to ribbon cable. Sure would be easier to connect up. Soldering wire to the pins just doesn’t excite me.

JohnC

4

Dear John

I have used 3 types of connector.

For single row

I have used the JYK type with crimp terminals see page 192 of Rapid Electronics catalog (UK).  I have used straight and 90 deg Headers.

In the catalog the Teminal housing is the JYK H2500-xx and the connectors are type P2500-xx and P2500R-xx; the terminals areT2500-02

I have also used the HE14 PCB connectors from AMP in both straight and right angle versions

I have purchased a crimp tool that is OK for both types above.  The cable have been made with ribbon cable stripped to the appropriate width.

I have used the ribbon cable with IDC connectors where double row connectors are required. eg Display.  You will need a different tool to do this.

I hope this may help.

Regards Robin