Volume Meter Build

[blearyeyes]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=231447448719

A bunch of 5 LED kits for 8 bucks...

[AntKnee]

I ordered one, too.
Let me know how your build goes. I am wondering how to split the signal properly.

[blearyeyes]

I received a couple of 10 LED meter kits from China. I'll post how they turn out...

[Guybrush]

Just built one of these up - https://www.tindie.com/products/kuzyatech/lm3916-led-bargraph-vu-meter-breakout-green/

I hooked it up to a 9vt power supply and to my guitar via a mono jack. As expected the output of the guitar is too low for the circuit to register properly. Even with the trim pot on the circuit board fully cranked I can only get the first LED to light.

Does anyone have any suggestions to increase the guitar output and so make the LED readout useable?

Thanks in advance.

[micromegas]

Schematic and instructions can be find here:
http://kuzyatech.com/lm3916-led-bargraph-vu-meter

You can check  valvewizard's vumeter that uses the same chip, and adjust the kit to it (schematic on page 9):
http://www.valvewizard.co.uk/glassblower.pdf

He seems to be using a level detector and a buffer but I only took a quick look. Here you have his notes about the vumeter:

My prototype GlassBlower turned out to be so useful as a general purpose preamp that I decided it would be nice to have some sort of metering, especially when driving other pedals since I don't really want to slam them with an excess of 9Vp-p.
The VU meter is done in the usual way by sending the audio to a peak level detector and then to an LM3916 audio-taper LED driver. Although this chip is designed to drive 10 LEDs, it is not easy to get the full scale out of it with only 9V available, so I used six LEDs. In any case, with six I managed to fit the whole thing into a standard small enclosure (Hammond 1590B equivalent). The lowest LED lights at about 60mVp-p, and the highest at 9.5Vp-p. Since I use electronic bypass the metering continues to work even in bypass mode- you don't get that with true bypass! This gives a really visual idea of how big raw guitar signals are (not very big!)
Current consumption = 15mA when active.

[AntKnee]

I just received my kit from china. Looks fairly simple to build. I don't yet know if I will need to look into some sort of amp for this, too. I'll post back up as soon as I build it.

[AntKnee]

Got mine built up, but it doesn't register anything from my pedal board. It will need some sort of amp, I assume. I have no idea how much signal it needs to hit the red.

I didn't use the supplied LEDs. I think the way I have it set up will be easier to mount in an enclosure. I have to drill a really straight line of holes, though.

[davent]

If you have or have access to a drill press, clamp a fence or straight edge to the press table so you can slide the enclosure against it as you move from hole to hole and you'll achieve your nice straight line. Precise layout and center punching goes a long as well.
dave