noob multimeter question

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: Joe., luketeaford, lisa, Kent

Post Reply
User avatar
phase ghost
Super Deluxe Wiggler
Posts: 1376
Joined: Thu Jan 21, 2010 11:44 am
Location: WV, USA

noob multimeter question

Post by phase ghost » Wed Mar 10, 2010 1:05 pm

I need to buy a multimeter, but I've never used one and I'm confused on a few things.

How do I measure voltage coming from a module? Do I get an adapter for a patch cable to plug into? Do I have to take it apart so I'm touching bare wire? I wouldn't plug it right into the jack would I?

I want to see what kind of voltage my existing modules are sending so I have an idea what to do with my own designs.

thanks!

modularland
Veteran Wiggler
Posts: 654
Joined: Tue Nov 17, 2009 5:19 pm
Location: New York Metro

Post by modularland » Wed Mar 10, 2010 1:20 pm

Take a spare cable, cut it, and attach alligator clips to the ground and hot parts of the wire, and clip them onto the clips of the multimeter.

Note that you wont see anything very interesting unless you are testing an on/off type function, because the voltage that comes from a modular synth is always in a state of flux.

A much more interesting tool is an oscilloscope, where you can see the voltage represented over time- this way you can see the shapes of waveforms- not only the VCO but also the ADSR, gates, etc...

A multimeter really wont be so useful for measuring anything but on / off signals like a pushbutton...

An oscilloscope is like a multimeter but displays the voltage over an adjustable amount of time... I especially like to visualize ADSRs so I can see exactly how the knobs are behaving.

Make sense?

Note you can get VST plugins taht emulate oscilloscopes, making the need for another piece of gear obsolete.

http://www.bluecataudio.com/Products/Pr ... eqAnalyst/
Steve L

User avatar
valis
aliens killed bigfoot
Posts: 2133
Joined: Tue Sep 30, 2008 3:53 pm
Location: on the palouse, usa

Re: noob multimeter question

Post by valis » Wed Mar 10, 2010 1:47 pm

phase ghost wrote:How do I measure voltage coming from a module
Red/Positive from the multimeter on the contact where the power enters the module.

Black/Ground on the ground.

The Greenlee DM-20 was my first decent DMM and I used the hell out of it and it always served me well. Now I have a nice Fluke DMM which allows me to measure AC, DC, Hz, etc. which may be more of what you're asking..

User avatar
phase ghost
Super Deluxe Wiggler
Posts: 1376
Joined: Thu Jan 21, 2010 11:44 am
Location: WV, USA

Post by phase ghost » Wed Mar 10, 2010 2:07 pm

Modularland - So you're saying I won't be able to tell if 2v or 5v or whatever is coming from a module with a multimeter? I was under the impression that's what they were used for.

User avatar
sduck
experimental use of gravity
Posts: 13858
Joined: Wed Feb 18, 2009 6:03 pm
Location: Vortepexaion, TN, USA

Post by sduck » Wed Mar 10, 2010 10:56 pm

Depends what you're measuring. Remember that vco's put out both positive and negative voltages, hopefully at equal amounts, so at audio rates it'll look like 0 volts to your dmm. Slow it down to lfo rates and you'll start to see the voltages change. But Modularland is right - for many things a scope is the way to go. But you can get started and do a lot of basic stuff with just a dmm, and the best way is to just go get a cheap one from rat shack or whatever and experiment - you'll get the hang of it pretty quickly.
flickr cloud of sound touyube NOT A MODERATOR ANYMORE

User avatar
wetterberg
Super Deluxe Wiggler
Posts: 7673
Joined: Thu Jul 24, 2008 5:31 pm
Location: Copenhagen, Denmark.

Post by wetterberg » Fri Mar 12, 2010 11:39 am

modularland wrote:Note you can get VST plugins taht emulate oscilloscopes, making the need for another piece of gear obsolete.
actually that is unfortunately not the case, as far as I can tell; I don't know of any audio interface that accepts DC signals, so visualising an ADSR is going to be dc blocked on the input. You might see a little peak, but it'll return to 0v on its own, even with static DC coming in.

Post Reply

Return to “Music Tech DIY”