[sdiy] Juno 6/60 SH rate for filter cv

[Tom Wiltshire]

On 18 Jul 2012, at 09:54, rburnett at richieburnett.co.uk wrote:

>> Stick a 'scope on the multiplexer select lines, maybe?  I'll dig my 106
>> out later and see what I can turn up.
>> 
>> --
>> Gordonjcp MM0YEQ
> 
> The DAC multiplexer refresh rate in the Juno 106 is 4.2ms.
> It's 4ms in the Alpha Junos and MKS-50 too.
> The JX-3P multiplexer refresh rate is 10ms.
> 
> I think it's a fair assumption that it will be somewhere in the single millisecond range for the Juno 60, as all of these synths use similar low-end 8-bit micros that were available at the time.  How accurately do you need to know the update rate?

Possibly, but the Juno60 situation isn't exactly the same. Instead of the uP having to generate the envelopes or the LFO (which would limit the maximum refresh rate) all it is having to do is generate incrementing mux/demux addresses. The Juno60 service manual claims a 1ms minimum attack time, and the mux/demux filter CV mixer is apparently able to capture that, so I'd expect several KHz rather than several hundred Hz.

Please someone with a Juno6/60 get the lid open and get a scope on those address lines!! We need to know!!

Thanks,
Tom