Having a little youtube dive for something to build and this pops up…
A VU meter that is a battery checker also. Would look better than just a blank, and im sure it wont take much to make it ‘useful’ for our needs.
My first thought is the simple mixer with passive thru’s on the inputs and a jack on the front of the VU panel.
And it may as well be a battery checker… because why the flip not eh!
What do you think? safe? not safe? will the E caps turn into micro fireworks XD
It looks like a nice and simple build, plus it makes it easier to see whats active if you stick them next to ur VCO VCA etc
I wonder whatever became of all those pretty little analogue vu-meters that used to festoon consumer hi-fi in the seventies. Replaced by LEDs, I suppose. I think my NAD component gear had all LEDs, which to their credit occupied much less space and were much easier to read.
I think they were probably useful on a mixing desk, but those things they used to put on everything from a radio tuner to a cassette deck were just there to look cool.
The LED level meter on my NAD cassette deck was all I needed. If the red LED flashed while I was checking the level before recording I knew the incoming signal was too fresh.
This works because its a voltage divider. The caps are to smooth it out. Diodes are to keep it one directional. Never built one, but should be safe, ive seen this design before. Sometimes you see an opamp for current regulation.
Thanks for the explanation! I wonder if this will handle -V and bipolar LEDs? Thinking if this can take inputs directly from an LFO to ‘VU’ Level then to mixer. Or, if it will only read V from the mixer safely.
I like the idea of it just being a passive unit built from spare bits. rather than having something all fancy pants and buffered.
its not like its a Nano, WS28… party mode thing, just a simple ‘Blank’ space filler that for some reason is also a battery tester lol
To be clear, I’m not saying it will work, just pointing out two issues that would need to be addressed. You can get bipolar electrolytic caps. Bipolar LEDs should be the kind with two leads.
Assuming you select resistors to get only 5mA thru each LED, that thing will still (try to) suck up to 50mA of your, usually, 1K impedence output… not sure that will work.
I used to use this one a lot. There is a linear and a log version. You can chain them together for more LEDs or you can multiplex one for a 10 x 10 display. https://www.ti.com/lit/ds/symlink/lm3914.pdf
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