Mutable Instruments CVPal

Anything modular synth related that is not format specific.

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mskala
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Post by mskala » Wed Aug 02, 2017 11:14 am

homeless_peep wrote:I wonder, is there a way to mod this in order to receive midi data through the usual 3 pin midi interface? I can sure fit a 3.5mm stereo jack there. Would that improve latency at all? I can figure out ways to power it properly from my rack, but my skills at coding are quite basic.
Unlikely. The so-called USB-MIDI protocol is not very similar to classic MIDI, and the CVpal works by speaking USB directly, not by translating it into a MIDI signal and decoding that. One could build a hardware MIDI interface and rewrite the firmware on the chip to work with it, but it would pretty much be designing a new module, not a "mod" of this one.

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Post by homeless_peep » Wed Aug 02, 2017 12:26 pm

mskala wrote: One could build a hardware MIDI interface and rewrite the firmware on the chip to work with it, but it would pretty much be designing a new module, not a "mod" of this one.
That's what I have in mind. There are pads on the PCB, so I can fit an optocoupler for the midi interface. I was hoping I can bypass USB operation entirely, and change the firmware to handle the usual MIDI messages, but use the same code for handling digital to analog conversions, polyphony and so on.
I didn't get the time to look at the firmware just yet though, it might be a lot more complicated than I think.

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Post by Maneville » Sun Dec 10, 2017 4:55 am

Apologies for resurrecting this thread a little, but a question: could I plug something like a games controller pad into this and use it as some kind of CV generating joystick input?

Cheers...M

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Post by hamildad » Sun Dec 10, 2017 7:43 am

you need to have a USB host to manage the controller to MIDI translation.

I'm thinking about trying to get a Raspberry Pi to do this, but I just need a few hours peace and quiet to dig into whats needed.

this is what gave me the idea.

https://stimresp.wordpress.com/2016/02/ ... midi-host/
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Post by Drakhe » Sun Dec 10, 2017 10:27 am

Maneville wrote:Apologies for resurrecting this thread a little, but a question: could I plug something like a games controller pad into this and use it as some kind of CV generating joystick input?

Cheers...M
Expert Sleepers FH-1 with latest firmware will do this

[video][/video]

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Post by Maneville » Sun Dec 10, 2017 2:10 pm

hamildad - thanks for the clarification. I guess it's more complex than I thought.

Drakhe - thanks for the video; I think this was the YT video I saw that prompted the idea in the first place. Something for the future, not least once I read up on what else the FH-1 can do.

Thanks, Gurus.

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Post by mskala » Sun Dec 10, 2017 4:27 pm

hamildad wrote:you need to have a USB host to manage the controller to MIDI translation.
Yeah, it's in big letters on the CVpal Web page and still a frequently asked question: the CVpal is a USB device, not a host. Devices plug into hosts, and hosts are basically computers. USB devices do not plug into each other. So you can't plug something like a USB-MIDI keyboard into a CVpal; instead, you have to plug the keyboard and the CVpal both into a computer.

One easy way to think of it is that hosts are what provide power to devices. With two devices plugged together and no host, where is the power supposed to come from? It'd be like trying to plug two lightbulbs into a power bar and have them light each other up without plugging any cord into the wall. However, that's only part of the story - there are protocol differences too, so even if you managed to power your devices in some other way, they couldn't communicate without a host. This design comes about because most people have more USB peripherals for their computers, than they have computers; so USB is designed to make the computer do as much of the work as possible (saves money because there's only one of it) and keep the circuitry in the devices to a minimum.

As others have said, there are other (much more complicated and expensive) modules you can get that will function as USB hosts in a Eurorack.

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Post by Zijnzijn Zijnzijn! » Tue Nov 06, 2018 8:44 pm

I wanna bump this thread up real quick - I'm thinking about snagging one of these to use with Max/MSP, sometimes for sending notes but especially for sending weird and wacky LFOs/envelopes/triggers/etc. Has anybody used this with Max with any success/horror stories?

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Post by hamildad » Wed Nov 07, 2018 5:04 am

It fine....

only issue is that MSP will convert envelopes,LFOs to MIDI and then back to signal, so there is some quantisation on way in and way out.

unlikely to be noticable, but the MIDI is an middle step thats technically not necessary.

If there is anyway you can snag a DC coupled interface/expert sleepers, you can cut out the MIDI altogether and just live in the land of Signal & V/Oct.

but grab one of these, enjoy it and when you grow out of it, you'll have saved enough for a ES or a MOTU.
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Post by dp » Mon Jan 28, 2019 6:39 am

I'm wondering if there would be any issues using 2 of them.

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Post by mqmq » Tue Jan 29, 2019 2:52 am

dp wrote:I'm wondering if there would be any issues using 2 of them.
Absolutely no issues ! You'll have to change the name of the second one in the code though. I have 2 and it's so much fun

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Post by dp » Tue Jan 29, 2019 5:11 am

Great thanks

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Post by mskala » Tue Jan 29, 2019 9:57 am

mqmq wrote:
dp wrote:I'm wondering if there would be any issues using 2 of them.
Absolutely no issues ! You'll have to change the name of the second one in the code though. I have 2 and it's so much fun
I'd call "you have to change the name in the code" a pretty serious "issue" - it raises the bar for the builder a lot by requiring them to be able to modify the firmware. However, it depends on the operating system on the computer. On my Linux system it works fine to use two CVpals without any firmware change. Some Mac users have reported needing firmware changes to run two. Windows has trouble with the CVpal even when there is only one.

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CVPal parts query

Post by Resonance » Wed Mar 06, 2019 2:21 am

Hi all. I’m doing a DIY CVPal and having trouble finding the right Mouser / Element14 part numbers for a few of the components.

1. zener diodes
2. 20mhz quartz crystal (the image in the assembly guide shows a multicomp F18MHL but I can’t seem to locate one)
3. 3.5mm jacks

It’s a discontinued product now so info is a bit scarce. If anyone has a BOM they could post it would be very useful.

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Post by Wartimetapestry » Wed Mar 06, 2019 2:29 am

I built this from mainly Tayda parts a couple of months ago -

https://www.taydaelectronics.com/20-000 ... ofile.html

https://www.taydaelectronics.com/1n4729 ... -3-6v.html

That's what I used for the Crystal and diode. No issues from the build at all.

Jack's I got from Thonk.

Hope this helps.

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Post by Resonance » Wed Mar 06, 2019 3:33 am

That certainly does help. Thank you.

I guess the jacks are Thonk PJ302M?

https://www.thonk.co.uk/shop/3-5mm-jacks/

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Post by Wartimetapestry » Wed Mar 06, 2019 3:54 am

PJ302M, that's the ones.

Sorry, I've just realized you said Mouser. I read it as Tayda in my haze this morning. I got to my final decision by scrutinizing a bunch of different data sheets and taking a calculated risk.

Cheers.

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Post by Wartimetapestry » Wed Mar 06, 2019 3:57 am


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Re: Mutable Instruments CVPal

Post by RenderDender » Wed Jan 29, 2020 5:34 am

Hey guys.
Sorry for bumping an old thread, but I've got a few questions regarding CVPal. The questions might be stupid, but there's almost zero information about cvpal on the internet. So:
1) Is that possible to use CVPal with Bitwig on Ubuntu? If not, what software do you use on linux?
2) I don't quite get what the "MODE's" on CVPal do. Can I just send 2 channels of CV or is it somehow connected to MIDI protocol and you can't avoid passing velocity or something else on the second channel?
3) Can I use 2-3 CVPals simultaneously? Do you have to change the firmware for this and flush it to the chip? Because I don't have a programmer at the moment and was thinking to get a preprogrammed chip.
4) Is it worth it to get CVPal in 2020 or should I stack some money and get an Expert Sleepers interface? What are your thoughts?

Thanks.

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Re: Mutable Instruments CVPal

Post by mskala » Wed Jan 29, 2020 1:30 pm

RenderDender wrote:
Wed Jan 29, 2020 5:34 am
1) Is that possible to use CVPal with Bitwig on Ubuntu? If not, what software do you use on linux?
I don't know Bitwig, but the CVpal is a class-compliant USB MIDI device and should work with all software that supports MIDI in general. I most often drive mine with midish (http://www.midish.org/), and with custom C code that calls the ALSA MIDI driver directly.
RenderDender wrote:
Wed Jan 29, 2020 5:34 am
2) I don't quite get what the "MODE's" on CVPal do. Can I just send 2 channels of CV or is it somehow connected to MIDI protocol and you can't avoid passing velocity or something else on the second channel?
You can choose different ways of controlling the outputs, by sending MIDI data on different MIDI channels. For instance, if you want it to take note-on/note-off messages (playing MIDI notes in the ordinary way) and have velocity control, you can send your notes on channel 1, and then every note sets both control voltages (pitch and velocity). If you want two independent voices (with just pitch control on each, no velocity) then you send the data for one voice on channel 3 and the other on channel 4 - and then they don't affect each other. There are other options under which it will take for instance MIDI control change messages instead of note-on/note-off. Those might be appropriate if you're using a controller with knobs instead of keys.
RenderDender wrote:
Wed Jan 29, 2020 5:34 am
3) Can I use 2-3 CVPals simultaneously? Do you have to change the firmware for this and flush it to the chip? Because I don't have a programmer at the moment and was thinking to get a preprogrammed chip.
I use two under Linux with no problems and no reprogramming. Some people have had trouble, but I think the issue was specific to the Macintosh drivers.
RenderDender wrote:
Wed Jan 29, 2020 5:34 am
4) Is it worth it to get CVPal in 2020 or should I stack some money and get an Expert Sleepers interface? What are your thoughts?
Depends what you want from it. The CVpal is no longer supported by Mutable Instruments, but it still does everything it always did, and is smaller and cheaper than most of Expert Sleepers' offerings.

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Re: Mutable Instruments CVPal

Post by RenderDender » Thu Jan 30, 2020 1:54 am

@mskala Cool, thank you!

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