The Buchla 200e presents a significant system integration challenge, with its 0 to +10v and 1.2v/oct interfacing standard. What this means is you really need to invest in an entire system all at once. By using Volta to integrate Buchla modules, the cost of entry is significantly lowered, because it is possible to start with a single Buchla module.
Volta also offers some advantages over using the Buchla MIDI decoder module. For example, in this video, we demonstrate a Buchla 261e oscillator (@ 1.2v/oct), played in unison with a TipTop Audio Z3000 (@ 1v/oct) with portamento. We also demonstrate three-way Buchla oscillator modulation synced to a project, which allows for real-time beat-synced host-based effects, which in this example is Audio Damage's Big Sequencer 2 effect plug-in. MOTU BPM is providing drums.
The oscilloscope software used is MOTU Cuemix FX which is included in a free software update for registered users of the Ultralite mk3, 896mk3 and 828mk3.
This video may be viewed in HD here.
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I was just thinking that the outputs of a MOTU audio interface are balanced and modular patch cables are unbalanced. Is it possible to send out 2 CV signals on the balanced cable and split them out to 2 TS cables? Kind of like an inset cable but the signals are going the same way instead of one in and out. Did that make sense?
ReplyDeleteSorry. Doesn't work that way. :)
ReplyDeleteHowever, this question is obliquely related to controlling the Buchla with the 896HD due to the DC coupling scheme it uses. Buchla owners who are interested in Volta read carefully: if you're interested in volta, the 896HD is the interface you need.
This is why: the 200e doesn't want to see negative control voltages. You need an interface that has serious output. The 896HD normally puts out around +3.6v. Due to the DC coupling scheme that the 896HD uses, if you short pins 1 and 3, you'll end up with a max voltage output of approximately +7.2v.
The 896mk3, which is currently manufactured, will _not_ work as the outputs are not DC coupled.
There is another caveat with the 200e and Volta - currently in volta, there is not a method to shift all voltage output to unipolar (all positive) voltage. In the demo, I'm using all positive voltage ramps to accomplish what you hear. This is a feature I'd like to add to Volta, but it is currently categorized as a 'wish list' feature and is not scheduled for the first release of Volta.
This is all very exciting! My idea for a 4 panel Buchla rack is becoming much more of a reality with your Volta video. The only downside is that I'm going to need to get another HD192 or figure out if I can link up an Apogee for my audio and the MOTU for CV.
ReplyDeleteI should probably know the answer to this but how did you make your voltage ramps positive if the Volta doesn't output positive only ramps?
The HD192 can be used with volta, but the DC coupling scheme isn't the same as the 896HD, so it outputs half the voltage as the 896HD making it unsuitable for 200e control.
ReplyDeleteThe 200e only responds to positive voltages, so your control range with volta gets cut in half. Therefore, it is critically important to use an interface with HOT outputs. The 896HD is the interface to use with the 200e.
I'm not sure if I could fully agree with the need to invest in a whole system at once. Something like the 291e Triple morphing filter does quite a bit with it's own self oscillation and Don certainly won't stop you from buying a small system.
ReplyDeleteAlso 1.2v/oct is annoying but not impossible achieve with some traditional midi2cv interfaces that have a wide range or use of any interface a simple mixer that works with DC (1 input 100% of 1v/oct, 2nd input at 20%, master out at 100%)
Speaking of advantages or disadvantages to the Buchla MIDI decoder and overall integration I would think Buchla's combined 10v trigger with a +5v gate would be a challenge
The 292e will open from the 896HD voltage output. The 281e will not. However, patching it through the 256e will. The 256e is an amazing module, BTW.
ReplyDeleteWhile there are advantages to controlling the 200e with Volta, it is still far from ideal. I don't want anyone to have any illusions about this. An ideal interface would be 0-10v with unipolar modulation sources. The 89HD voltage output comes close, and a software update could address the unipolar issue. For most scenarios, the MIDI translator module is better for sending note information to the 261e.
The fact that it works at all is due to my own interest in the 200e and my desire to find a way - any way - that would allow me to assemble a system piecemeal.
I'd think the 281e wants a trigger. Interesting about the 256e. I don't have one now but intend to get one. I guess it (and the non inverting amplitude on the 210e for that matter) is unipolar. So as a processor it might not do all that's expected especially with a negative slope
ReplyDeleteI guess Harvestman has a eurorack adapter module on the back burner.
Nothing is going to completely stop you from just buying some modules (as long as you can afford it). There might just be some snags depending on your goals. There are smaller boxes and boats available and it's possible to trade them in later for bigger ones. The only thing that will slow you down is Don tends to take many seasons to ship. So at least my buy one module at a time turned into buying a bunch over time, waiting a a bit of a while and eventually receiving them.
Is there any plan for a dedicated MOTU output only box?
ReplyDeleteJust tested: the original MOTU 896 also outputs +7.5v
ReplyDeleteThere is one on ebay currently @ $100
The two main XLR outputs on the 828mk3 output +9.25v (!) holy smokes.
Is it possible to use an 828 and a HD192 in the same set up?
ReplyDeleteYes, you can use aggregate devices with Volta. You can try setting this up now in AudioMIDI Setup. Go to the Audio menu and select 'Open Agregate Device Editor..." This opens a window that enables you to setup a virtual device that is an aggregate of multiple devices.
ReplyDeleteIs their any chance this will work with a vst host i.e Cubase 5.
ReplyDeleteI would of course need to buy a Motu soundcard (should be good for sales) but I feel you will lose a lot of sale if it is AU only.
Someone has allready written a very basic vst plugin that works with MOTU soundcards for controlling analog synths so it can be done, I would much rather you guys did a vst version for sure :)
Will yu be bringing out a dedicated hardware unit to go with this?
Why is it you never answer any of my questions?
ReplyDeleteI think they are very relevant to your product.
Samuel:
ReplyDelete1) "never" is a long time. "never" is much longer than two days.
2) Matthew is probably not at liberty to talk about MOTU's activities until they are publicly announced.
Just my $0.02 worth, of course.
Hi Matthew - I'm eagerly waiting for Volta and a secondhand 896HD to arrive any day now. You mention above shorting pins 2 and 3... Could you explain (for soldering iron neophytes like me) what exactly needs to happen (from xlr to banana) for the 896HD to drive Buchla. Thanks so much !!
ReplyDeletePin 2 should be tip. This should be soldered to a banana, and this is used to modulate whatever you want on the Buchla.
ReplyDeletePins 1&3 should be combined and sent to ground to the Buchla. So, what you eventually end up with is pins 1&3 on all outputs connected to each other and connected to the ground input on the back of the Buchla.
The Buchla only wants to see positive voltages. As you can imagine, from sharing the ground of all these signals, sending multiple bi-polar signals to the Buchla will result in major weirdness and unpredictability.
Currently, most of the sources from Volta are bi-polar, so this means that you can only use the positive half of the ramp automation for modulation and your tracking range is reduced. I would like to add a function that limits all sources to unipolar output so volta will be more useful with the Buchla, but this is not the case currently.
Hope this helps.
Cool. Thanks !!
ReplyDeleteI'm looking forward to see how Volta develops. Certainly some Buchla optimization would be welcome... as would MS-20/50/etc.
And others have mentioned, it would be so cool if MOTU made a Volta specific interface box (with CV record and other exciting modular goodies mmmm :-))) Nice work !!!