2 sets of drawbars

[Simon]

Hello. I have built a hammond organ clone with the hx3 curcuit board. Om thinking about upgrading the organ with a original b3 drawbar and switch panel. I wonder if anyone knows how to make double drawbar sets work. I want to be able to switch beteende the sets with 2 buttuns like you do with b and bflat inverted keys.

Regards Simon Jonsson

[happyfreddy]

hi,
The simpliest way is using the old Preset 12 board.

We have talked about this in following thread
viewtopic.php?f=3&t=467

The switching between the drawbarsets is realized with the IC´s 4053
Schematics You find in github zip file unzip and then go to : * / Platinen / Preset 12 old version
These 4053 IC switch the slides of the drawbarsets.
For simply switching between the sets You only need the buttons Preset 1 = live ( set B ) and Preset 2 ( set A# )

In Remote software You must chose between real switches or push buttons because preset board is connected to I2C bus ( PL 4 )

[Simon]

Hi. Thanks for the reply. I can only find preset 12.2 the new version on the keyboardpartner store. Will that one work for me?

Regards Simon Jonsson

[happyfreddy]

No, with this new board You only can switch the presets itself
This new board requires also the new drawbar boards
These new drawbarboards have the switching IC´s on board.
Because these boards run with 3,3 volts these IC´s are of type 74 HC 4053

With this new preset 12 board there is no way to switch the drawbar sets too when You use other types of drawbars like those from
old Hammond organs

For realizing this ( without preset switching ) You need following

PCB ( view from top side )

Screenshot 2016-05-18 18.24.27.png

PCB layout

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component side ( red lines are jumpers )

Screenshot 2016-05-18 18.25.35.png

PCB top side

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schematic

Screenshot 2016-05-18 19.57.47.png

schematic

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with this board and a simple rocker switch etc ( ON - OFF ) You can switch between two drawbarsets

This board must be connected to + 5 volts ( because of standard 4053 IC´s

The drawbarsets itself run at 3,3 volt ( connected via flatcable from analog input plug on HX 3 board )