I’m looking at building LMNC’s 1v/octave VCO as my first project. Does anyone know approximately how much current this could draw? Ref:
I scanned through the forum for keywords like milliamps, current etc but couldn’t find an answer.
I scanned through the forum for keywords like milliamps, current etc but couldn’t find an answer.
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not sure anyone’s posted this number . but I would guess under 50ma there’s not much to it . but thats not a scientific answer . sorry I don’t have one for you , not my thing .
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Don’t know, but the Kassutronics VCO 3340 is said to draw 15 mA +12 V and 15 mA -12V. It looks to me like a fairly similar circuit to the LMNC. There are other 3340 VCOs with much higher current specs, circa 60 mA per rail or more (e.g. the VCO Maximus) but maybe because of extra components.
If I had one of these VCOs I’d use my new current tester on it, but I don’t…
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Thanks.
I ask because, before I spend time on a proper power supply, I’m thinking a board-mounted dual-output DC-DC converter module might serve my purpose of playing with low current projects like this.
For example, if 83mA per rail is enough for this VCO, I’m wondering if I can use this:
Isolated Module DC DC Converter 2 Output 12V -12V 83mA, 83mA 10.8V - 13.2V Input https://www.digikey.com/product-detail/en/CUI+Inc./PCN2-S12-D12-S/102-3937-ND/6181032
Curious to know whether this could work, or if there’s something I’m not realizing. I do understand that this wouldn’t leave much room to expand…
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Sure, assuming you have a regular wall wart to power it. I’d be surprised if it couldn’t drive a single module.
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Right on, I was hoping that was the case. If I get hooked on this stuff, I will obviously have to accommodate more current. Although, it feels like I’m already hooked 
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Bad news. If you write like this, you’ve already got it, so my tip (I’m also a beginner), buy a 12v AC wallwart for € 8 on ebay and the frequency central PSU board for € 8 and you’re on the safe side Side and have rest for now. If you have gained some experience, you can build a second PSU board yourself with this layout.
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As soon as I graduate from the breadboard to the molten lead thingy, I promise I will try to build this.
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this is what I have been using on my work bench the power board PCB is from from frequency central
https://frequencycentral.co.uk/product/fc-power/
the wall wart is from a surplus place you can pick them up all over the net .
and I built the the hook up board from strip board to accommodate the different power configurations I my need to plug in . the led’s on the power supply board are nice , if you plug something in that has a short you know right away because they will dim .
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With the combination of devicex you are definitely on the safe side !
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Datasheets say <10 mA for the 3340, 2×2.5 mA + output load for the TL072s. Seems 20 mA or so should be enough.
EDIT: Here’s a similar DC/DC converter driving a similar 3340 build. I’ll see if I can find the time to measure the current (may take a few days).
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