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Testing the noise section voltage.
Posted: Jun 11th, '14, 21:38
by JakeE
Im not quite sure about measuring this
am I using the right setting? Does my multimeter have enough decimal places.
Thanks

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Re: Testing the noise section voltage.
Posted: Jun 12th, '14, 17:13
by ebbflo
you appear to have it set correctly but that dmm may not have the resolution you need. did you try it on dc m200? see what that does
Re: Testing the noise section voltage.
Posted: Jun 12th, '14, 21:34
by JakeE
I dont get anything on the 200m but on the next one up (2) I get about .253 with the trimmer turned fully clockwise.
Tried to up load image but was having trouble with it.
Re: Testing the noise section voltage.
Posted: Jun 13th, '14, 02:18
by zmb
JakeE wrote:I dont get anything on the 200m but on the next one up (2) I get about .253 with the trimmer turned fully clockwise.
Tried to up load image but was having trouble with it.
I have a similar DMM, the AC voltmeter only goes down to 200V. I got it to 0.1 and then adjusted by ear. But for more precision the soundcard oscilloscope may help but I'm not sure, I'm going to try that out soon too.
http://www.zeitnitz.de/Christian/scope_en
Re: Testing the noise section voltage.
Posted: Jun 13th, '14, 10:19
by JakeE
Okay thanks how do you trim it by ear? do you have to wait till its built or are there some points you can use a audio probe thing.
Don't think be able to use a soundcard oscilloscope as Im having trouble finding a free or cheap one for mac.
Re: Testing the noise section voltage.
Posted: Jun 13th, '14, 15:42
by ebbflo
That's the trimmer that you may need to replace a resistor in order to get it down to the correct setting.
I have a multi meter like yours too but my yocto is already cased and its kind of a pain to get to now
you may want to invest in a slightly better dmm, its worth having a couple. I bought an extech 430 for this project and it is fairly priced.
Re: Testing the noise section voltage.
Posted: Jun 13th, '14, 18:52
by lfo2vco
JakeE wrote:Okay thanks how do you trim it by ear? do you have to wait till its built or are there some points you can use a audio probe thing.
Don't think be able to use a soundcard oscilloscope as Im having trouble finding a free or cheap one for mac.
Here you go Jake:
http://www.arizona-software.ch/audioxplorer/
Works fine for me on OS X 10.9, 10.8 & 10.7 (I have been using it a while).

Re: Testing the noise section voltage.
Posted: Jun 13th, '14, 22:33
by zmb
JakeE wrote:Okay thanks how do you trim it by ear? do you have to wait till its built or are there some points you can use a audio probe thing.
Don't think be able to use a soundcard oscilloscope as Im having trouble finding a free or cheap one for mac.
Well what I mean is I adjust until the snare drum / handclap/ toms etc. sound right to me. I don't know if it's 130.0mVAC but if it sounds good then whatever.
Re: Testing the noise section voltage.
Posted: Jun 14th, '14, 00:28
by JakeE
@lfo2vco Great thanks for that I obviously didn't google hard enough.
Cant really afford another dmm I've got other music gear to buy haha thanks anyway
I will try the oscilloscope and if it doesn't work I will go by ear
cheers
Re: Testing the noise section voltage.
Posted: Jun 16th, '14, 20:55
by ElSchtroumpf
I had the same problem with my cheapo DMM, so today I ordered this one :
http://www.conrad.com/ce/en/product/109 ... V?ref=list
It measures AC voltage down to 0,1mV and costs 30€, for the people in Europe.