[sdiy] midi to cvand gate , negative output? good idea ?

[John L Marshall]

It seems to me that many VCOs should be capable of a 20 octave range. That
is, you can use a control voltage from +10 volts to -10 volts. The VCO may
not have precise tracking over extended range. But, precise tracking at the
extremes may not be so important.

If the MIDI to CV converter only has positive values it can be routed
through a CV mixer to shift the range negative. If the MIDI to CV  converter
has a 5 octave range of 0 to +5 volts it could be shifted to from -2 volts
to +3 volts. A pot and DC mixer could be added to the MIDI to CV converter
to shift the range down or up.

The CV input to the VCO is usually a DC mixer with a bunch of inputs;
frequency control pot, fine frequency control pot, keyboard CV, and a bunch
of CVs through attenuators.

John

----- Original Message -----
From: Peter B <dragonservicing at success4business.com>
To: synth Diy list <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, January 10, 2002 3:40 PM
Subject: [sdiy] midi to cvand gate , negative output? good idea ?


> Hi,
> just wondered if people thought having the ability to houtput a negative
> voltage on a Midi to cv unit was a good idea ?
> I recently was calibrating a Roland piece of gear that was being used
> with a kenton unit,and I was suprised when I found that when I selected
> the lowest note on the controlling keyboard I got -1 volt out from the
> kenton.[on the control volt output]
> I know that some Midi to cv units won't output such large negative
> signals ,and was just wondering if it was possible that some synths
> would only accept positive signals .
> regards Peter
>
> --
>