[sdiy] Quantizer project.. incoming CV's switching point to change to quantized output CV's ...

Brian Willoughby brianw at audiobanshee.com
Sat Jul 10 00:59:43 CEST 2021

In my project, panel real estate is mostly taken up by the CV output jacks themselves. Things like 1.0V/octave versus 1.2V/octave are part of setup, along with configuration for Gate polarity and voltage, as well as assigning different jacks to different voices/parameters. So, it's literally a free feature - not out of the way.

Good to know that a lot of Buchla and clone modules are calibrated for 1.2V/octave. That reinforces my desire to provide compatibility as a configuration option.



On Jul 8, 2021, at 19:23, Nathan Trites <nathan at idmclassics.net> wrote:
> Many 200 series clones and third party Buchla format modules are still calibrated for 1.2v/oct. and most integrating them with other systems have various modules to scale to and from 1v. A typical situation would be doing all your sequencing and quantizing in euro, and then a format converter to get the higher CV and gates. 
> Panel real estate is a huge deal though so if you aren't designing it for standalone use, or it's not complicated enough to cover most of a panel, you may not want to go out of your way to include 1.2v. 
> Nathan
> On Wed, Jul 7, 2021 at 12:46 AM Brian Willoughby <brianw at audiobanshee.com> wrote:
>> Thanks for the experience, Mark.
>> I learned about "1.2V/Oct" while attempting to research the most exhaustive list of features needed for compatibility with everything out there. If you're saying the Buchla never made a 1.2V/8va synth - or at least not anything that was cross-compatible with anything else, even other another Buchla unit - then I guess it's not worth bothering to support this. Of course, the design I'm working on could easily support 1.2V/octave without any extra costs because it would just be another setting / option.
>> I've never owned a Buchla, but I've been to a few shows in San Francisco and elsewhere that featured them. Out of my price range. ;-)
>> So... if you plug two 1V/octave cables in, they get summed to 2V/octave? Reminds me of getting big pitch bends out of the Matrix-12 (or Matrix-6) by applying the same modulation two or three times.
>> Brian
>> On Jul 6, 2021, at 05:57, mark verbos via Synth-diy <synth-diy at synth-diy.org> wrote:
>> > Nice enough idea Brian, but my research shows that 1.2V/Oct is a myth. Buchla 100 systems have a switch to select between the front panel control and the untrimmed CV input. It is exponential in response, but trimming was moot given that there was no keyboard with an output other than tunable keys. The early 200 series VCOs only have CV ins with attenuators as there was not a piano layout type keyboard until the Music Easel (218). Once there was a keyboard that was trimmed, the scale was 2v/octave. This made sense in a 0-15v CV world, which Buchla lived in until he decided to change that out to 0-10v when he switched to blue knobs. The 259, which came out in the late 70s is still 2v/octave at its keyboard input. In 2003 when the 200e was announced, the 1.2v/octave standard was declared.The 225e doesn’t have any trimming on its CV outputs and the one I have puts out around 1.14v/octave. To the 200e, that doesn’t matter anyway, because there is an internal digital bus for the pitch, which controls digital oscillators. When I have made VCOs to be used in 200e systems, I trimmed them to my 225e, but there is no guarantee that they will track on someone else’s. There is a guarantee that a MIDI to CV converter or a quantizer that is trimmed to 1.2v/octave won’t track with a VCO that is trimmed to a 225e though. Paradoxically, a Buchla 225e cannot be used to make a Buchla 258 play in tune unless you plug the CV into both CV inputs.
>> > 
>> > Mark

More information about the Synth-diy mailing list