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November 2013

DIY Connector with GR synths

DIY Connector with GR synths

View of DIY connector, GR-300 and GR-100 in the background.

Connector operational

Connector operational

The connector correctly mounted and working in a very dirty GR-100!

DIY Connector with cover fitted

DIY Connector with cover fitted

The second cable is complete, with the sliding outer cover fitted and held by two side mounted self-tapping screws. Two 3/8" 2-56 bolts secure the connector base to the bent angle. There are some small crystals of epoxy resin on the connector pins.

The connector pins side view

The connector pins side view

A side view of the connector, the pins aren't perfectly straight, but the female connector has sufficient play in it to accept them anyway.

After drying, the aligned connector pins

After drying, the aligned connector pins

The pins turned out to align pretty well, despite my poor drilling.

Edge connector pins glued

Edge connector pins glued

Here the edge connector pins have been glued with 24 hour epoxy glue, together with a 1/2" 2-56 bolt and are drying with the pins gently positioned into a female Roland 24 pin connector. I happened to have one spare, but you could use a synth's connector for the alignment. This will compensate for the inaccuracy of the drilling. For the first couple of hours drying, I had set the connector 5mm distance from another piece of perspex, held apart by bolts to ensure the connector pins all extend to the correct depth. The 1/2" bolt turned out to descend the correct depth due to the thickness of the perspex, otherwise I would have cut it down with the Dremel.

Base of DIY connector

Base of DIY connector

After drilling the perspex base, even with a drill press, I was off in my alignment…grrr. This was a combination of using a broken 1/32" drill bit, inaccuracy of the Dremel drill press base and that I didn't centerpunch the marked drill holes accurately enough, nor checked the prospective drill hole position sufficiently. Other photos indicate that this level of inaccuracy didn't turn out to be a problem in practice. The edges of the perspex in this photo are pretty rough, due to cutting the perspex with a hacksaw by hand (no bandsaw available). After this photo, I flattened and straightened the edges with a hand file. Some of the edge connector pins and 1" 2-56 bolt for reference. I ended up using a 1/2" bolt as a centre pin.

With the cover installed

With the cover installed

With the cover slid down over the bent angle, the connector itself still stands proud, different from the original Roland connectors. However, this is fine for the male connectors since they adjoin the guitar synths, which won't be moved around, compared to the female connectors adjoining the guitars. For these cables, the other end connecting the guitars use DB-25 male connectors plugging into DB-25 females on the guitar.

After wiring the original connector

After wiring the original connector

After soldering the wires of the Belkin cable to the connector, with heat shrink tubing in place.

Aluminium tubing cut, angle cut, drilled and bent

Aluminium tubing cut, angle cut, drilled and bent

The aluminium tubing outer covers have been cut and hand filed, the 1/2" aluminium angle has been cut, drilled and bent. Shown with the stripped wires of a Belkin cable and an original Roland 24 pin connector.

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