Firstly, the DoepferMBP25 works well, and does exactly what it suggests - it converts keystrokes to midi. However, unlike other Doepfer units, it's midi sockets are on fly cables and not on the board, so be prepared to desolder these so that they can be mounted on the box and re-attach.
The Fatar Keybed is a workable unit, and easy to cut to length. But that also means it's pretty flexible. You need to anchor it very well to a very stiff base. It will need extra anchor points, I used the gaps in the missing black notes to add screw down points.
To remove the extra C, you need to cut through the tracks on the circuit board. That means you have to put fly cables in to replace the missing part of the circuit board. Best way is to scratch some of the green resin off the remaining track and 'tin' the copper, solder the wire from this to the underside of the corresponding component.
Lastly, you must be prepared to remake all the key contact joints on the circuit board. Don't chase individual faults, just resolder the lot. The soldering on both my sets were poor, but resoldering was a complete cure, there were no mechanical issues.Don't let this put you off!
So it's cheap and effective, and not difficult to build - but needs a bit of work.
