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I have compaired my dats vs a B and K lcr and they measured the same. You may want to check what frequency you are measuring at and make sure there is no metal close by.
I have 5 Hz - 20kHz showing in DATS
Try calibrating it first.
Did that before taking the measurement.
1k is the most common.
Is that the only coil measuring off?
I just measured a Solen 0.51mH, 16awg and got 0.5864 mH
Erse steel core 4.0 mH got 4.7 mH
Does your version use an external resistor for calibration?
yes, 10000 ohm
Make sure the device is set to 44.1kHz in Windows.
https://www.parts-express.com/pedocs/manuals/DATS V3 Quick Start.pdf
All that checks out fine.
You mean 1000, right?
Interesting issue, do you have a DMM you can check the resistor against?
I find a LOT of coils are about +0.5mH high from manufacturers, but it's well within tolerance.
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My old WT3 used a 1kOhm resistor, but regardless I don't think that's the issue as the DCR appears accurate. If it were a 1k resistor calibrated at 10K, you'd expect abnormally low DCR, and I would think abnormally low inductor values as well. The key is to make sure that the DATS draws a perfect straight line at 10kOhms when you run the calibration, as well the short circuit calibration should draw a perfect straight line at 0 Ohms. Any wiggles or curves is a calibration failure.
Well within tolerance? 3.0 vs 3.5mH is 16.7% off, where Solen specifies a tolerance of only 1%. Now 1% might be a tad optimistic, I wouldn't expect a 20% tolerance level on Solen inductors. Either way, it's always good to keep at least one "known good" part on hand so if there's any question of the accuracy of the test gear you have that known good frame of reference to check against.
0.5mH deviation from advertised on any coil under 10mH is not within tolerance on coils sold for audio. Perhaps 0.05mH. For a .20mH coil, 0.5 would be 25% off-spec. I would accept .205, but no higher.
Leon, if we were closer, I could throw them on my Der EE meter. It is more accurate than the WT3/DATS/LIMP method. I suspect it is a wonky lead or a resistor that has drifted for whatever reason.
I find a lot of Erse that are so far off I think they could be mislabeled. I have yet to find a manufactured coil that measured low.
I got a decent 3.5 digit LCR MM for about $40 from Aliexpress. When you need it, you need it!
Now Im curious - when I get home I'll pull some Erse coils and measure. I don't seem to remember having issues in the past, though.
Grr... being 1400 miles from home is frustrating at times.
I sent Chris at Solen an email to measure one of their 3.0 mH coils.
I had a similar episode a couple of weeks ago. I use a Praxis script to do LCR measurements and was scavenging some surplus crossover boards. All of my inductor values were 20-30% high. I took out some known (or highly suspected) good inductors and they also measured equally high. I then suspected a setting issue, as I had been doing frequency, impedance, and LCR measurements during the same session. After restarting Praxis and rerunning the script, my measurements were normal. It would be helpful if I had actually figured out what the setting issue was, but I at least confirmed that was the issue. Your situation seems familiar, so I still suspect something got jacked up with a setting. I'm not sure what it will take to make DATS happy (reinstall software, uninstall/reinstall drivers, etc.).
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I measured some resistors that come very close to the stated value.
Then I suspect Solen has a winder or meter out of whack. Sanity checks are important in trouble shooting.
Chris said to make sure I measure them at 1KHz.
Solen uses a very accurate Stanford Research SR720 to measure them
They may only be measuring 1 out of every hundred.
Sorry- mistyped there. I do mean 0.05mH for the smaller coils. Some of the larger valued P-cores have been more than that off, but always higher. I don't use them much anymore so that eliminates some of the problems.
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I have never measured a coil that was less than it was supposed be. Generally they are a lttle larger (1-3% IME).
Not sure what to do at this point. I have some coils to measure but don't know what to trust. Why would DATS have that option if it doesn't work or am I missing something?
I have had some Erse coils be under value as well.
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