Topic: DIY VU meters for any source ...

[twatts (pants are so over-rated...)]

would using the line out on the nomad drain the battery of the nomad faster?

from what i remember it's always "active" even if you're not using it.

Not sure here, but I think you can turn them off, or turn one or both on...  I remember trying to go line-out inot my stereo and pulling my hair out while not getting signal...  Finally I did some scrolling around and found the line-out on/off...

T

[mattb]

I think that's right. I haven't looked into it much yet. I could sacrafice a little battery time for good meters. I usually still have 3/4 of a charge left after a typical show anyway.

[mattb]

Here's a question: Does anyone know or have a feeling about putting a meter on the INPUT on my AD-20? I could pretty easily tap that and basically make a Y connection so that signal still goes to the AD-20 Pre AND to the little meter. My concern is this could degrade the signal going into the AD-20 and I don't want to do that. But if it wouldn't matter it sure would be a cool AD-20 mod, no?
The inputs in an AD-20 go in via a ribbon cable. I was thinking I'd just make a small ribbon cable piece with a female jack that I could plug the original input cable into and split it without actually modifying the AD-20. I could undo it by unplugging my mod.
What do you guys think?

[mattb]

Wait a sec. I don't want to do that because I want levels AFTER the gain stage, so scrap that idea. I'll just put it on the line out of my jb3...

[mirth]

Hey Nick - I suck at soldering. How much would you charge to build something like these?

[BJ]

yaya...i need one too...how much do to sling your way?  except..I want one with more lights...cuase my skillz sux...I can't keep steady meters until at least the second song..doh!

[caymanreview]

you can buy those meters allready assembled and just plug and play with a 1/8" mini

i had a link and was gonna do this before i sold my ua5 and jb3, but dont have it anymore

[ChrisV]

I've seen a few units but they've costed ~100$.   If anyone finds a relatively cheap one or an easy one to create I'd definately be interested.  I too would like one with a few more lights, something like 10 would be ideal.   I've seen a few possible DIY ones but they are all like 10V+.  If anyone sees a 9V one so you could run off a standard 9V battery that would be awesome.

[caymanreview]

the one i saw was like 40 and was all put together ready to attach a input of your choice (ie miniplug or rca) and ran off 9v. it was 40 bucks or less as i recall... wish i still had the link

[BobW]

Does this thing care about the voltage input ?
Adding a regulation circuit might be needed to keep it accurate.
Test with full charge and again after a few hour's use. Use the same input level and see if meter leds read the same level.

Nick, which way to mount LEDs? Red or Green toward the Cal Pots ?

[BJ]

Ok...here is what i came up with so far....

for the leds...a ten led (2 board) VU meter ..measuring approx 2.7in x 1.5in
it comes assembled for $40..Requires a 10-15vdc power supply at 250mA.
http://www.hobbytron.net/vk4305.html

If i could get 3 others to go in on this($6.5 ea.)  these look to be very sturdy..and exaclty the right size...they are clear plastic.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3184114144&category=36553

so it looks to be about a $50 project...
when they "assemble" to they calibrate for you also?  It's just "ready" to plug in power and inputs(rca or mini)??  cuase this seems very easy....if it is...

thanx.

[BobW]

10 led boards are 12v @ 250 ma, almost as much power as the UA-5 itself.

I think that calibration should be done to the individual unit, as output will vary.  Someone should test this thing will fully charged and near-spent cells.


At the other end of the Outboard monitor spectrum, I guess, would be the Neutrik ML-1.
Meters, spectrum analysis, mini-O-Scope.
Very cool toy.

Anyone playing with one ?

[ChrisV]

Yeah, hobbytron has quite a few listed here:
http://www.hobbytron.net/audiosub.html

Not quite sure which one would work out the best for what I want.   Possibly this one(although it wouldn't be for both channels, but not really that big of a deal for me) which could run off 9V:
http://www.hobbytron.net/CK134.html

But other ones look nicer and have a that black cover, wonder if they are better calibrated too?  Not all the technical of a person myself so I don't know for example what they mean by "INDICATION RANGE: 0dB = 0.775mVrms" and other terms listed there.

Money could be saved on buying the kits and assembling them yourself(not sure how hard they would be).   Looks like on some of them there is a much bigger price difference to do it $23.96 compared to $40.95 assembled whereas the other one is only $15.95 compared to $19.95 assembled.   If I went would that one definately just buy it assembled since it is only 4 bucks more.

[BobW]

Not all the technical of a person myself so I don't know for example what they mean by "INDICATION RANGE: 0dB = 0.775mVrms" and other terms listed there.

My first thought is, "That's just plain wrong."
0.775mVrms is +20DB, isn't it ?

So I checked, and it's correct. 0.775mVrms = 0db

Click Here for Details

Geeky, yes, but it is fact. dbU or decibel units are actually a voltage measurement, just as you might measure 120 Volts at a wall outlet, but much, much lower.  

Deep geek note:
RMS means Root Mean Squared, a math term for the effective potential which an AC signal has.  This is a sort of "average" of the Peaks and Valleys of the Alternating Current waveform that accounts for the sine waveshape.

Take a short course on Decibels from the University of South Wales Here

[mattb]

I bought the CanaKit meter Nick originally posted about. My problem is, the output of the JB3 only barely makes the first light or two light up. I can't redline it with the calibration turned all the way up. So that one is no good for the JB3, but may be fine for something else that can give a little more juice on the output. Anyone want to buy mine to give it a go with another device? LMK. It's just collecting dust now.
If anyone finds a good one that takes the JB3's output range well I'd love to hear about it!