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Are you sure they'll be oxidised ? The ones I used back in 70s all had gold plated wires and busses so they couldn't oxidise. MIght be a bit of crap on them but never anything worse.</div>
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<div dir="ltr" id="divRplyFwdMsg"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of drheqx via Synth-diy <synth-diy@synth-diy.org><br>
<b>Sent:</b> 16 May 2025 13:07<br>
<b>To:</b> rburnett@richieburnett.co.uk <rburnett@richieburnett.co.uk><br>
<b>Cc:</b> synth-diy mailing list <synth-diy@synth-diy.org><br>
<b>Subject:</b> Re: [sdiy] Hammond Aurora Keybeds</span>
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<div style="direction: ltr;">Yes sir, and they are. They're not the multi-bus wire type but they are direct metal strip on wire and they're going to be oxidized to a certain degree. </div>
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<div style="direction: ltr;">On Fri, May 16, 2025 at 6:17 AM <<a href="mailto:rburnett@richieburnett.co.uk" id="OWA443fd18d-371d-7ea4-5088-eed08664ae99" class="OWAAutoLink">rburnett@richieburnett.co.uk</a>> wrote:</div>
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<div>You can also do whatever flavour of switch de-bouncing that you want in<br>
software, if the key contacts are a bit old and scratchy!<br>
<br>
-Richie,<br>
<br>
<br>
<br>
On 2025-05-16 03:54, Ben Bradley via Synth-diy wrote:<br>
> "Each key closes a switch to a common bus."<br>
><br>
> There's a couple things you need to make a "true analog" mono<br>
> keyboard. First is a constant current source to drive the resistor<br>
> divider, so that when more than one key is pressed the voltage remains<br>
> that of the lowest or highest key (unless you WANT a weird off-pitch<br>
> note effect when pressing more than one key). The other is a separate<br>
> switch at every key that closes AFTER the key that gives the pitch<br>
> voltage as the key goes down, so that the proper voltage is sampled<br>
> and kept when the key is released. This is also the gate/trigger<br>
> output. Presuming there are several common busses, you need to bend<br>
> the contacts on each key to make sure these close in proper sequence.<br>
><br>
> I don't see a problem of being off-pitch with a resistive divider, as<br>
> 1 percent resistors are cheap thesedays, whereas 1970s keyboards may<br>
> have used 5, 10 or even 20 percent tolerance resistors.<br>
><br>
> But still, I'd as soon make a digital circuit to scan/read all the<br>
> separate inputs, one for each key, scan it into a buffer with a<br>
> microcontroller and do the highest/lowest/latest keydown logic in<br>
> software and the usual DAC for control voltage output.<br>
><br>
> On Wed, 14 May 2025 at 22:54, drheqx via Synth-diy<br>
> <<a href="mailto:synth-diy@synth-diy.org" id="OWA9fbe8dcc-1f15-b555-4a33-843173d0d4ee" class="OWAAutoLink">synth-diy@synth-diy.org</a>> wrote:<br>
>><br>
>> Hi all,<br>
>><br>
>> I have the keybeds and draw bars etc. from a Hammond Aurora organ.<br>
>><br>
>> These are not matrix type keybeds. Each key closes a switch to a<br>
>> common bus.<br>
>><br>
>> Is this a good time for me to consider doing a volt<br>
>> /octave keyboard controller?<br>
>><br>
>> I definitely don't want to midify these. That would be a waste. I<br>
>> was considering building a voice per key synth because i love these<br>
>> key beds and it would be so unique, but I'm short on time like so many<br>
>> of us.<br>
>><br>
>> Anyone know of a good kit to make a 1v/ oct controller, maybe with<br>
>> some added features.<br>
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