The second I saw these VU meter kits available online I hoked out one with included dial meters out and bought it, less than a tenner too.
A couple of weeks later I had a decent looking board and had grabbed a 12vac power supply that should have been 9v but all the other boards of the same design were listed for 12v input so yeah, 12v is likely a good bet. Be sure to get an AC power supply, which can be tricky due to the joys of searches and titling.
With some beers on a Friday night I soldered all the leads for attaching to the board, having RCA female sockets about was handy, they’re cheap and easily acquired – just search panel mount RCA plug.
I chopped USB cables since each thing needs four conductors and nothing’s high current. For the VU dials themselves there was no documentation and nothing in English in the instructions, with some digging I got the answer. They’re marked up in the photo, since I didn’t know which pins were which without some checking to be sure.
The input and output don’t actually need full wires, you can jumper them together and just take one set of wires to the board. I did it this was as I didn’t have a case in mind until later on but I want to see these working.
Apart from the VU meters everything else is easy to understand and the board includes labeling for the various screw down connectors.
Calibration is easy, initially these won’t move at all on a line level source, maybe yours will but these were set up for a powered input I expect, turning the screws on top of the adjustment pots will get you where you needed to be, I’d suggest playing music until they’re swinging about in the range then play a tone at your expected max volume and dial them in to that to get an even response.
In terms of calibrating to specific level outputs, it’s possible but if there’s a computer involved you probably have multiple volume controls in a chain to make things more entertaining. I set these to a rough line level of the computer because they’re mainly for my entertainment.
I’d recommend these as a fun thing to make for your audio setup, beyond coarse metering of peaks these aren’t much use to a sound engineer. Unless it’s just adding some extra dials for the DFA factor.
The cigar box
I looked around for something I wanted these to live in for a while and didn’t really settle on anything, eventually I just wanted it done and grabbed a cigar box off the shit we like looking at shelves and started attacking it with a hole saw.
I like the cigar box, it works with my beat up wharfedales and my ratty Rotel, the meters look well in it but something was missing.
A totally unnecessary and vastly overrated chunky switch completes this, especially because the dials swing up nicely with an inrush spike when you flick it on.
Are they worth it
Absolutely, I had fun building this and I love the dials, along with the cigar box look. The backlighting is very dim and so warm it’s almost pinkish rather than amber but the cost is miniscule for a very cool audio accessory and project.