Using a Multi-Meter to calibrate DA

[Kyle Ashley]

If I'm using my DMM to calibrate my DA, would I set the function switch to AC voltage or DC voltage?

[zmix]

If you want to measure the signal coming out of the D/A converter use the AC volts function of your meter. If you are using a standard "+4dBu" level, send a 1khz tone out of the converter, with the send level set to your reference (-18, -20, -14, whatever you decide to use) and calibrate the converter output so that it produces 1.23Vac

[Kyle Ashley]

Thanks zmix!

[gyraf]

..that is, if your voltmeter is accurate at that frequency. Many aren't. Probably you'd be better off using 200Hz or so as testtone..

Jakob E.

[zmix]

Originally Posted by gyraf

..that is, if your voltmeter is accurate at that frequency. Many aren't. Probably you'd be better off using 200Hz or so as testtone..

Jakob E.

This is nonsense. Look at the specification sheet packed with the meter. Even the cheapest DVM has accuracy greater than 5% accross the audio spectrum and it's best to measure in the center of the desired spectrum. You can additionally check the readings at 20 and 20K hz if you like, but 1K is a standard refernce for a reason.

[Jim Williams]

If you want an accurate reading you will need an RMS detector DVM. Fluke makes great ones and some have ac to db ranging on them for audio level measurements.

Jim Williams
Audio Upgrades

[tINY]

For a hand-held meter, check the spec. A lot of the true-RMS handhelds are only accurate to around 200 or 500 Hz. That's plenty for troubleshooting any power system and that's what most of them get used for.



-tINY

[zmix]

Kyle, why not tell us exactly what model DVM you have, so we can all rest knowing that your accuracy at some arbitrary frequency is assured????

[Jim Williams]

Fluke 8060A. King of the hand helds.

Jim Williams
Audio Upgrades

[zmix]

Not your meter, Jim! I meant that rather than all these senseless assertions that the original poster's meter is NOT accurate, why don't we determine what he's using and obviate all the speculation???

-CZ

[Kyle Ashley]

I must admit, I have a Leviton model that cost about $40. I have been considering getting one of the Fluke models however. Thanks for the recommendation Jim

[Kev]

Originally Posted by zmix

This is nonsense. Look at the specification sheet packed with the meter. Even the cheapest DVM has accuracy greater than 5% accross the audio spectrum ...
... all these senseless assertions that the original poster's meter is NOT accurate, ...

nonsense ... senseless

I have a few DVM's of different brands AND two of the same brand.
I don't think any of them give the same results at 1K
... that is when using the DAW's test signal generator.

can't be bothered giving the meter brands and model numbers as we have already done this a couple of times on a few tech forums.

[zmix]

Originally Posted by Kev

can't be bothered giving the meter brands and model numbers as we have already done this a couple of times on a few tech forums.

We are trying to be helpful here.
can you bother yourself to read the posts here before copping such a dismissive attitude?

Here are the cliff notes:

The question was about D/A calibration using a DVM.
The procedure was given.
Internet forum noise was generated about meter accuracy.
Alternate, non standard procedures were suggested.
More supposition about meter accuracy.
A suggestion to the original poster was made asking him for the model number of his meter in the hope that it could determined whether or not his actual meter would be accurate enough for the procedure.

More forum noise...

[zmix]

Kyle,
I cannot find any data for a Leviton Multimeter. I would highly reccommend that you purchase the Fluke meter that Jim uses. A decent meter is a standard piece of studio gear.


http://www.fluke.com/

[Ziggy!!]

As opposed to your dismissive attitude displayed in your original post to Jakob??

[Kyle Ashley]

One Fluke 8060A has been purchased. Thank you!

[Kev]

Originally Posted by Ziggy!!

As opposed to your dismissive attitude displayed in your original post to Jakob??

thanks Ziggy , that was my point

zmix gave a spot on answer to the original post.
Jakob just wanted to add a little note about accuracy and the faults that can occur. We did have confusion at Tech Talk on this very subject.
He could have also added a note about the effects of termination but chose to keep it simple.
... then this is all just forum noise anyway.

When it comes to DIY and helping people interface equipment in there studios,
I think Jakob and I have a very long track record.

I have posted pictures and model numbers of enough occasions and a search of the net may even find them.

The Meta threads at the LAB have a wealth of information and the guys that post there have carried on the great tradition started at Tech Talk and Group DIY.
Sure the old Group DIY pages are being removed, but in time, will find their way back up on the net and will be given an update.
Much has changed in many aspects of Recording and DIY in the past 5 to 6 years and things like cheap DVM's have got much better and much cheaper.

The Fluke is great, but not every one has the money or access to such items. Jakob was answering the direct question here BUT also answering a wider question for ALL readers of this forum.
It was good advice.

It also should be noted that many people reading and posting on this forum and many like it, use English as best they can. English could be their second language.

For more info on interfacing and specs try
Rane
http://www.rane.com/
http://www.rane.com/library.html
http://www.rane.com/digi-dic.html

but do check out the tech notes and white papers
"Understanding Headphone Power Requirements"
and the Dynamics section is a good read.

Analog Devices dB calculator
http://www.analog.com/Analog_Root/st...dbconvert.html
remember to change the Z to 600



The accuracy of the sine wave can have a bearing on the results given by the DVM.

A decent meter is a standard piece of studio gear.

As zmix suggests, a DVM is a handy studio tool and for some might be " a standard piece of studio gear".
It can test 9 volt stomp batteries too.
I tend to rely on an oscilloscope for these things but I don't expect an operator to want one near by while recording or think they should ... but a tech might.

and I think that every studio should have a couple of simple handheld VU meters
with multi levels and terminations ... again do a search


but then, I guess this is all just .... " More forum noise..."