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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Tue Apr 23, 2013 3:52 pm Post subject:
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Dave Kendall wrote: | axg20202 If its output is hardwired to the next stage, you can omit this resistor - it's only there as protection for the opamp when patching. |
...by this do you mean it should be jumpered on the board or just not installed? |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Wed Apr 24, 2013 1:35 am Post subject:
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axg20202 wrote: | The tough part of the design will be the volume control - there is no simple solution for this. It's a shame the guy that posted his coloured film button design only stopped by to post that one comment and photo but no details. |
I use breath control for volume on these instrument types, but of course that's not going to be common or easy to set up.
I actually liked the simplicity of the volume control on Wendy Carlos's Circon used in "The Shinning"... a simple pot with a lever on it that used a rubber band to return. I was thinking of putting that together and stumbled upon the idea that a device might already be out there (and in abundance) that was designed for this kind of thing. Sort of.
And so I found a reason to actually buy a Guitar Hero controller ($5 at a 2nd hand shop) and wired up the whammy bar's pot to my Moogerfooger CP-250. It worked nicely, as is.
I was surprised how well this controls synths with direct CV modulation...
It seems the orginal volume button on the Martenot was exceptionally responsive, and I don't know how close this comes. It's also no where near as nice as a breath controller. But it was musically effective and smooth, even with very wide modulation (though not shown in the vid).
I think this could well modulate volume/brightness for a Martenot controller.
Here's the short demo vid. I was kind of surprised this works so well.
http://www.youtube.com/watch?v=aqPcIm3v8O8&feature=youtu.be
and some pictures...
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Wed Apr 24, 2013 3:00 am Post subject:
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Brilliant!
Edit: ...and so much more fluid than the rack and pinion method I was thinking about..... Last edited by axg20202 on Wed Apr 24, 2013 5:25 am; edited 1 time in total |
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Dave Kendall
Joined: May 26, 2007 Posts: 421 Location: England
Audio files: 3
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Posted: Wed Apr 24, 2013 4:04 am Post subject:
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@axg20202
Jumpered.
cheers,
Dave _________________ "Everything in moderation, including moderation" |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Wed Apr 24, 2013 4:38 am Post subject:
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OK, thought so, but thanks for confirming. |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Mon Apr 29, 2013 5:08 am Post subject:
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Would anyone be so kind as to check my layout for a dual offset circuit?
By the way, the socket is for Eurorack/Doepfer-style power. From the left, the vertical pairs are -12v, ground, ground, ground, +12v, not connected (+5v), not connected (CV), not connected (gate). |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Thu May 02, 2013 3:57 am Post subject:
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Well, OK then - asking too much there I think
I'll be making this little PCB over the weekend. If it works as expected, I'll post the PCB image so that folks can make their own if they want. |
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tojpeters
Joined: Feb 04, 2013 Posts: 22 Location: cali (far north)
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Posted: Fri May 03, 2013 11:36 am Post subject:
here's mine |
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this it what I'm working on. just a rough draft, I'm making a couple changes.
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Sat May 04, 2013 6:30 pm Post subject:
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tojpeters , this is looking so cool. Check out those tubes... can't wait to hear this instrument! |
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tojpeters
Joined: Feb 04, 2013 Posts: 22 Location: cali (far north)
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Posted: Sun May 05, 2013 7:04 am Post subject:
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The design for the tube synth is by Eric Barbour from the CGS site with some minor changes. Just a rough first try to check concept and gearing. I now need more parts. I was going to use 1 pot to control the anode voltage on the vco tube and the other to sweep the filter in a pitch tracking way. But the filter sweep needs to be 60% of the range of the frequency pot,and I can get more range by using the second pot to control grid voltage. The keys send cv to the grid also.When using the ribbon I unpatch the cv from the keys to the vco and just use the keys to send gate signal.The freq pitch control will be handled by a third pot/pulley to get the gearing closer. This works great so far. Still experimenting before I decide on final design. I was going to mount a FSR408 touch sensitive resistor in front of ribbon for modulation/gate but now I'm not sure it is necessary. next I need to hook up my tuner and mark out all the c notes and see if they are consistent sweeping both up and down. |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Sun May 05, 2013 1:02 pm Post subject:
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OK, this is the final verified PCB that I have made and tested. Its free for anyone to use for personal use. The image should be printed onto transfer blue and applied to copper clad board for etching. Parts placement is a few posts back.
Now that I have the offset working (with a multiturn 100K pot) using this circuit, I'll move on to building the pulley and ring setup. |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Mon May 06, 2013 10:22 am Post subject:
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Infrablue wrote: | I found a reason to actually buy a Guitar Hero controller ($5 at a 2nd hand shop) and wired up the whammy bar's pot to my Moogerfooger CP-250. I think this could well modulate volume/brightness for a Martenot controller. |
Could you shed some light on how this was wired up? Was it literally wired as a volume control on the audio signal or did you have it rigged up to actually control CV for, perhaps, a VCA? I'd like to implement the latter and thinking about how this pot/lever arrangement could do it without having to send the audio from the synth to the controller and back again. |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Mon May 06, 2013 10:41 pm Post subject:
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axg20202 wrote: | Infrablue wrote: | I found a reason to actually buy a Guitar Hero controller ($5 at a 2nd hand shop) and wired up the whammy bar's pot to my Moogerfooger CP-250. I think this could well modulate volume/brightness for a Martenot controller. |
Could you shed some light on how this was wired up? Was it literally wired as a volume control on the audio signal or did you have it rigged up to actually control CV for, perhaps, a VCA? I'd like to implement the latter and thinking about how this pot/lever arrangement could do it without having to send the audio from the synth to the controller and back again. |
I hooked it up by sending the three leads of the Guitar Hero pot through a TRS quarter inch jack - ended cable to one of the powered CV inputs of a Moogerfooger CP-251. This powers it and let's it be output as a CV out basically. Another way of looking at this is... it fully takes the place of Moog's EP-2 Expression Pedal. So any input that uses that sort of standard pedal will use this as a control source.
You could also send it to replace various pots in a modular module and that would translate to VCA or a simple CV etc.
I plugged it right into the expression pedal input of my A6 Andromeda and it worked right there as well.
I was surprised how nicely it worked as is with the pot it came with. |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Mon May 06, 2013 10:50 pm Post subject:
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I just finished my breath controlled Martenot instrument- finally - and put together a demo video. I'm pretty excited to get to this point on it!
I've called it the Artemis (as the exposed loop reminds me of a bow, and Artemis was a Greek Huntress Goddess with a bow).
Thanks so much for all the incredible help here on this project!
I gave it it's own topic in DIY... but wanted to give the heads up here too...
here's the YouTube Video....
http://www.youtube.com/watch?v=fRdTDTK3QTQ
Last edited by Infrablue on Tue May 07, 2013 9:37 am; edited 1 time in total |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Tue May 07, 2013 1:51 am Post subject:
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Infrablue wrote: |
I hooked it up by sending the three leads of the Guitar Hero pot through a TRS quarter inch jack - ended cable to one of the powered CV inputs of a Moogerfooger CP-251. This powers it and let's it be output as a CV out basically. Another way of looking at this is... it fully takes the place of Moog's EP-2 Expression Pedal. So any input that uses that sort of standard pedal will use this as a control source. |
Ah, OK, thanks. In that setup, the pot is varying a voltage that is provided by the input of the CP-251 itself. I guess I will have to create something that generates the voltage for control by the pot, which then passes the varying voltage to the CV input of the VCA. I will probably combine this function with the offset board I've made and build a single 'Ondes' module for my modular synth that will handle the pitch and volume CVs. I will probably use a DIN connector or something so that the Ondes board is connected to it via a single cable. |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Tue May 07, 2013 8:18 am Post subject:
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axg20202 wrote: | Infrablue wrote: |
I hooked it up by sending the three leads of the Guitar Hero pot through a TRS quarter inch jack - ended cable to one of the powered CV inputs of a Moogerfooger CP-251. This powers it and let's it be output as a CV out basically. Another way of looking at this is... it fully takes the place of Moog's EP-2 Expression Pedal. So any input that uses that sort of standard pedal will use this as a control source. |
Ah, OK, thanks. In that setup, the pot is varying a voltage that is provided by the input of the CP-251 itself. I guess I will have to create something that generates the voltage for control by the pot, which then passes the varying voltage to the CV input of the VCA. I will probably combine this function with the offset board I've made and build a single 'Ondes' module for my modular synth that will handle the pitch and volume CVs. I will probably use a DIN connector or something so that the Ondes board is connected to it via a single cable. |
I would also suggest sending CV to a filter, so that louder gets brighter as well. Something really nice in expression, even if just in small amounts. |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Tue May 07, 2013 8:29 am Post subject:
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Good idea.
In terms of generating the CV for volume/filter cutoff, I'm thinking the same offset circuit above might be useful here assuming it can be rigged to output a voltage with no signal input |
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tojpeters
Joined: Feb 04, 2013 Posts: 22 Location: cali (far north)
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Posted: Tue May 07, 2013 9:23 am Post subject:
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really like the trill. really nice work. |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Tue May 07, 2013 9:30 am Post subject:
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tojpeters wrote: | really like the trill. really nice work. | Thanks so much! It sure takes some getting used to but does bring something new to the performance... mixing that with some sort of continual pitch controller.... |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Tue May 07, 2013 9:34 am Post subject:
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axg20202 wrote: | Good idea.
In terms of generating the CV for volume/filter cutoff, I'm thinking the same offset circuit above might be useful here assuming it can be rigged to output a voltage with no signal input |
This is sure the ideal... having it generate a voltage with no input.
I actually think sending the dynamic articulation to just a VCF is all that is needed. A totally resonant free VCF is still close enough to a VCA... and even that kind of filter emulates well the brightness response in acoustic instruments.
But then, if it just sends CV, having it mult'ed and hitting all sorts of things on a modular can get fun too. |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Wed May 08, 2013 5:39 am Post subject:
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Well, the circuit does output voltage with no external CV input, which is obvious really given how the supply voltage is fed into the circuit. It looks as though I will have to redesign my PCB above to include 3 offset circuits: first one provides the pitch variation controlled by the pulley system, the second takes the output of that and allows overall tuning, and the third is a separate offset dedicated to VCA/VCF control CV generation to add dynamics via another performance control e.g. the sprung lever and pot suggestion above.
I now see how useful this simple circuit is. It can be used for pretty much any form of control modulation, particularly from external physical controllers. All that is needed is some imagination as to how to vary the resistance to generate the modulation: pots, LDRs, vactrol, pressure sensitive pads, etc etc.
My pulleys are in the mail...... |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
Audio files: 212
G2 patch files: 60
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Posted: Sun May 12, 2013 10:59 am Post subject:
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Infrablue wrote: | I just finished my breath controlled Martenot instrument- |
Brilliant. I like the trill gizmo very much and the breath controller adds a great deal of expressiveness.
_________________ --Howard
my music and other stuff |
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axg20202
Joined: Mar 11, 2013 Posts: 20 Location: London
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Posted: Tue May 14, 2013 7:06 am Post subject:
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Infrablue wrote: | tojpeters wrote: | really like the trill. really nice work. | Thanks so much! It sure takes some getting used to but does bring something new to the performance... mixing that with some sort of continual pitch controller.... |
Sorry if I missed the detail earlier in this large thread, but can you provide more details on the trill setup? What are the switches you used? I assume these are momentary switches that add a resistor in series/parallel to the pitch control, but can you provide more technical details on how this was implemented? How did you select values for the various intervals you have available? |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Tue May 14, 2013 9:02 am Post subject:
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axg20202 wrote: | Infrablue wrote: | tojpeters wrote: | really like the trill. really nice work. | Thanks so much! It sure takes some getting used to but does bring something new to the performance... mixing that with some sort of continual pitch controller.... |
Sorry if I missed the detail earlier in this large thread, but can you provide more details on the trill setup? What are the switches you used? I assume these are momentary switches that add a resistor in series/parallel to the pitch control, but can you provide more technical details on how this was implemented? How did you select values for the various intervals you have available? |
Here is where I owe so much to Nyle Steiner and his Electronic Valve Instrument... it's a synth you play like a trumpet. I play that instrument, and my Artemis is wired into one of those, including it's "valves". So my top three "trill keys" are trill keys on an EVI, which raise pitch various steps. Next row down are the more standard EVI fingerings, which take pitch down at the same intervals a trumpet does. Then I added 2 posts with keys that trill up an octave and down a fifth. The fifth down is also a pretty hidden key on the EVI which is like lipping a trumpet down to the lower half of a given octave. On the EVI these are microprocessed to then put out voltages or resistances to the CV controlled oscillator.
So I could just do that because I have an EVI and wired into it. I'm just really not skilled or educated in electronics.
I have thought over how I'd do this if I didn't have an EVI. Firstly, that's really more keys than needed. If I ever get a company to make this controller, I would recommend 3 main trill keys (to raise a 3rd, step, and half step) and for sure throw in the octave trill... maybe the best one to have to use with a martenot or even a ribbon...
To do that, what I would have to do is get, for instance, the doepfer module that adds discrete CV voltages and then tune them for the job and set up trigger switches.
Or... and I've tried this out... use a normal keyboard (could be a small usb type) and have them ultimately send key values. It would be a little overkill for a trill type thing but works. The original Ondes Martenot had a keyboard as well but I have never seen it played at the same time as the ring/loop, so I don't know if that was ever seen as a good approach or use. But I have tried this with ribbon and with the Martenot style and it can be used to great effect. It's more a matter of focusing the music more on the continuous controller and just accent with keys.
Still, rather than keys, I'd prefer 3 trill keys and a 4th post or other key for octaves. My next demo will have some passages with the octave just trilling along through a slow melody and it's a really nice sound. 3 or 4 is great... I added more just because it was easy having an EVI and because I'm pretty practiced at EVI and so I sort of built one into my marteno. I can even just play it like an EVI and use the loop not at all or just for vibrato. But it's still better just use the EVI controller if that's what I'm up to.
Especially with a standard approach not using breath, one would better use three or four keys reachable above an expression button, perhaps an expression button for the palm of the hand to press with fingers comfortably reaching above to trills.
Also... Silent Way or Volta controlled by any sort of small midi pad/switch/OSC on an iPhone etc would do this well.
But that's how I would have to... many of you here could wire this up fine. CV switches to alter pitch pretty much, as you said from the start. |
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Infrablue
Joined: Dec 29, 2011 Posts: 131 Location: Utah
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Posted: Tue May 14, 2013 9:15 am Post subject:
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... This video has some examples of ribbon playing, accented a little with keys on the left hand. And then also some EVI playing. A funny secret on that part is the EVI that day happened to malfunction and the 3rd valve wasn't working.... so I had to play stuff that just used the first two valves... which worked ok using less western style scales. The music in the opening credits is also EVI on the melody.
Here's that youtube video...
http://www.youtube.com/watch?v=eh1-A_dYY6Y |
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