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trav
Joined: Sep 11, 2012 Posts: 108 Location: Auckland
Audio files: 16
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Posted: Mon Oct 27, 2014 9:03 pm Post subject:
CV for Lunetta |
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So I am planning a new modular and thinking about CVs. For Lunetta purposes, would it be useful to buffer distributed CVs? Also, could your usual transistor LED driver be adapted as a visual indicator of control voltage? Applications are stepped voltage into a 4046 VCO or the 4066 "VCA of sorts" or such like, but I was thinking of making a general purpose CV router module. |
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DUBmatze
Joined: Feb 18, 2013 Posts: 150 Location: south Germaica (schwabilon)
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Posted: Tue Oct 28, 2014 2:08 am Post subject:
Re: CV for Lunetta |
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trav wrote: | Also, could your usual transistor LED driver be adapted as a visual indicator of control voltage? | i have seen Eurorack modules for CV indication... so why not.
i use a analog 15v VU meter for that
But why transistors? you can use a Driver IC like 3914/3915 and a LED bar == 2 parts
maybe you can use the driver with some inverters to get some new digital Outs for your Lunetta |
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piedwagtail
Joined: Apr 15, 2006 Posts: 297 Location: shoreditch
Audio files: 3
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Posted: Tue Oct 28, 2014 3:49 am Post subject:
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Ray at MFOS has a Multi-function module that might be the ticket:
https://www.youtube.com/watch?v=7l6JGudok4Y
Features
1. LED Voltage Level Meter Totally cool looking.
2. Two 3 input DC voltage mixers with offset adjust and normal and inverted outputs.
3. Linear Lag Processor (long and short time select).
4. RC Lag Processor (long and short time select).
Quote: | A great assortment of functions in one module. Two 3 input DC voltage mixers with normal and inverted output, a linear lag processor, an RC lag processor and a LED voltage level meter. The voltage meter looks cool and lets you have a graphical idea of where that voltage level you like to use to modulate your filter or vca is so that later repeating it will be easier.
Although simple in nature the voltmeter is useful and has several input ranges (+/-1V, +/-5V and +/-10V). Whereas an analog or even a digital meter takes time to find the level this circuit lights the LED immediately giving you a rough idea of the voltage level you're looking at even when it is changing rapidly. The DC mixers let you mix LFO outputs or any voltage sources. The lag processors both give plenty of range to go from almost immediate voltage following to delays lasting many seconds before the output voltage arrives at the level fed into the input. |
( I have one populated but unfinished!)
Robert |
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trav
Joined: Sep 11, 2012 Posts: 108 Location: Auckland
Audio files: 16
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Posted: Thu Oct 30, 2014 7:57 pm Post subject:
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Thanks, guys. Probably the simple LED driver will do for the indication. MFOS also does this:
http://www.musicfromouterspace.com/analogsynth_new/CVANDGATEDIST/CVANDGATEDIST.html
I guess the other part of my question is about the sort of CVs a lunetta generates. From what I have seen and experimented with, these are mostly resistor ladders, so the CV range is from 0 to just under supply voltage, depending on how many bits there are. From looking quickly at the LM3914 the range should only go as high as about 1.5V below supply, so I guess I will need to attenuate that (correct me if I'm wrong). Also, is buffering required? what would be the detriment of a passive multiple? |
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elektrouwe
Joined: May 27, 2012 Posts: 143 Location: Germany
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Posted: Fri Oct 31, 2014 1:55 am Post subject:
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trav wrote: | ... LM3914 t... |
not really a Lunetta style chip. Also not CMOS Lunetta but maybe a bit closer:
I suggested a LM324 solution here :
http://www.sequencer.de/synthesizer/viewtopic.php?f=13&t=89665
you can use GND instead of V- for unipolar use and expand the resolution with a wlonger resistor ladder and more opamps if required |
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