40000 counts or 4 3/4 multimeter for calibration audio gear. - Page 1
Forum section: electronics / testgear

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 01:34:26 am
content: Hey!So i know this is similar to the old bad "hey what should i buy" but i'm asking anyways because i think my case is a bit different, maybe not.. you tell me..Basicly i need a multimeter with at least 40000 counts or 4 3/4 for calibration of audio gear equipment.I looked at a lot of them but i'm sure i missed some.It's kinda hard to find using the search, it just shows posts from almost 3 years old...Is there a list of multimeter with at least 40000 counts somewhere?I found in this jungle of chinese copies and legit brands, some that might be good for me.I'm not a professional in this domain, but i don't want to pay for something that will fail or display the wrong values.So i guess below 300usd would be perfect...I ended up with this list:- Fluke 287- Extech EX530- Brymen BM869S- UNI-T UNIT UT71D- Amprobe Am-140-A- Voltcraft VC870If that UT71D didn't look so sketchy i would have bought it right away... also the youtube teardowns didn't helped...I have to say i'm not going to use high voltage or anything like that, it's more for calibration of precise audio gear, most often under 20v, 12v most of the time max.Sorry if this has been asked but usualy this kind of post is everytime related to the basic 4000-6000 counts, i just can't get this, it's not enough.Thanks

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 01:55:05 am
content: Quote from: blueskull on October 31, 2016, 01:40:59 amBecause it's kinda 100$ more than the 287, at least from what i can find online right now... :S

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 02:05:38 am
content: Quote from: blueskull on October 31, 2016, 02:01:38 amWait for powering it up is fine for me, no stress here heheheBut the continuity test should beep fast...It's way over my budget... what is the best altertative to theses nice high resolution multimeters?I don't care about being safe in extreme environement, i will only use it for low voltage under 20v and always inside my comfy lab. lol

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 02:14:28 am
content: Added the Amprobe Am-140-A to that list.. seems like a good one and cheaper right?

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 02:20:55 am
content: Quote from: Nrkb on October 31, 2016, 02:14:28 amyeah but the continuity test on this one is really slow :S

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 02:25:15 am
content: Quote from: blueskull on October 31, 2016, 02:21:28 amoh really they are the same?The Amprobe AM-140A is 100$ CAD cheaper than the brymen 857

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 03:39:42 am
content: Hm i just see on a youtube video you can get 500 000 counts on the Amprobe AM-140-A with a button top right.Wtf is it? Magic button? I guess there's some drawbacks?

author: singapol
author_rank: Frequent Contributor
timestamp: October 31, 2016, 03:46:16 am
content: Nrkb,By calibrating audio gear equipment you really mean adjusting bias pots of power amps? Actually IMO a 40000 count DMM may be overkill although it's nice to have as an hobbyist there can never be too many meters.QuoteLet me illustrate by my own experience...I have UT139C 6000 count (fast beeper and more) ,UT61E 20K count and an old fluke77 3000 count. Just for fun I upgraded fluke77 with better voltage reference and change some resistors to 0.1%.I thought that will do it (give me more accurate reading but now after having compared and measured the same circuit like wall ACv and Dcv they have different readings (I'm not expecting identical digit for digit reading at least for for 1st. 3 digits I even use UT61 to adjust reference pot of 77) of course many will chime ah.. there are tolerances of components so now I'm not sure which meter is closer to the truth.now I think I will hook up a voltage reference and maybe buy a used 4 1/2 20000 count or 5 1/5 digit (300k count) and play with them to cross reference.The moral of the story as someone pointed out is although you may have more resolution (more digits) but that does not equate to accuracy unless your meter is calibrated/compared relatively to some standard or another more accurate meter. So he goes on to say with respect to specs. a 6.5 digit DMM is comparable to a 4.5 digit one in terms of % accuracy.Now I don't want to go into voltnut territory where it will drive you nuts pun intended.What I want to emphasize is voltage standards are spec. to temperature, air pressure and otherphysical properties that in essence there is no absolute accuracy as such and the experts have coined the term"uncertainy error" to take into account of errors relative to the meter reading. I learned a little because of this episode. Anyway it's likely your amp's adjust pot is only 1 turn vs 10 turn or more types. After you adjusted to the best accuracy then it will drift as soon as your screw driver is lifted from it.If you want bang for $buck get a UT139C 6000 count and UT71e or if you prefer a little luxury BM857 and you still have some change left over for other things. Again have at least 2 meters for sanity check.

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 03:58:30 am
content: Yeah i know it's a lot but it need that resolution and good accuracy. Mainly for some oscillators tuning / precise control voltage outputs, maybe something else in the near future.

author: singapol
author_rank: Frequent Contributor
timestamp: October 31, 2016, 04:12:06 am
content: Quote from: Nrkb on October 31, 2016, 03:58:30 amFor oscillators..how do you know they are bang on target frequency without a frequency counter percentage wise ( time nut territory.) For DC adjustments you need to know the equipments specs. Then forPS please do some reading of relevant subjects for better appreciation and understanding for sanity.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: October 31, 2016, 04:18:14 am
content: You would be happy with a keithley 2015. 6.5 digits, true rms, frequency counter, plus internal dds. $350.it's bench-top, but will do everything audio.http://www.partsconnexion.com/78916a.html

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 04:20:20 am
content: Quote from: singapol on October 31, 2016, 04:12:06 amDude lol... its modules that need to be calibrated to output cv into oscillators that must be in tune with each other... thanks for your awesome comment

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 04:21:51 am
content: Quote from: RandallMcRee on October 31, 2016, 04:18:14 amNice thanks for the suggestion, a bit more than i want idealy to spend but it looks really nice.I'm leaning to the Amprobe Am-140-A right now... i just seen a youtube review in 4 parts, it looks like its really accurate, responsive and has the resolution i'm after.

author: Lightages
author_rank: Unknown
timestamp: October 31, 2016, 06:01:04 am
content: The UT71E is not a more modern model of the UT71D. They are from the same line of models, UT71X, and they have different intended use and capabilities.The UT71D has more internal memory recording space. The UT71E was made for making power measurements. Neither are designed nor built to their CAT ratings and should never be used outside of CATII IMHO. Of the two, the UT71D is what would be preferred.IMHO the AM-140-A, Extech MM560 and BM857S should all be considered the same. They are, basically.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: October 31, 2016, 06:13:25 am
content: Quote from: Nrkb on October 31, 2016, 04:21:51 amIMO the 2015 (or another benchtop model if you find a deal) is absolutely the right way to go here. Bench DMMs are simply in a completely different class from these handheld things. In particular the audio measurements of the 2015 (THD etc) make it an excellent match for your use case. You won't find those measurements on a handheld meter!In general I think people who turn to handheld meters for precision are barking up the wrong tree. I used to suffer from a similar delusion and lusted after a Fluke 289 (after having one at a previous job)... then I came to my senses and lusted after a HPAgisight 34465A(still the best value in high end DMMs but far outside your budget). Then at work there was a budget closeout and a 34465A appeared (worth every penny so far, we really should have spent the money sooner; I don't know how we got along without one before). Now I have correspondingly set my sights a bit higher and am angling for a N9020B or equivalent RTSA, but that's neither here nor there....

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 06:31:08 am
content: Quote from: exmadscientist on October 31, 2016, 06:13:25 amHey i'm still open to suggestions, by reading this thread, could you recommend one under 300$ ?

author: Alex Nikitin
author_rank: Super Contributor
timestamp: October 31, 2016, 10:18:52 am
content: Quote from: Nrkb on October 31, 2016, 04:21:51 amIf you are OK with a bench meter, than the Keithley 2015 is an absolute bargain, as the original price for a new one was what - $9K ? You'll get a very accurate 6 1/2 digits meter , a distortion analyser and an audio generator in one unit which can also be remotely controlled from a PC.CheersAlex

author: RoGeorge
author_rank: Super Contributor
timestamp: October 31, 2016, 10:23:13 am
content: Metrix mtx3283 - 100 000 counts

author: Mark Hennessy
author_rank: Frequent Contributor
timestamp: October 31, 2016, 03:36:06 pm
content: If you're OK with a bench meter, but can't afford the 2015THD, look for the Fluke 45.It's 100,000 count, and has dB and power modes, which are useful for audio work. The dual-display mode is occasionally handy. Mine was less than £100, but that was before Dave's teardown:

author: nanofrog
author_rank: Super Contributor
timestamp: October 31, 2016, 03:58:34 pm
content: FWIW, the least expensive source to get Brymen is from TME.eu (located in Poland). Shipping is quite reasonable, and quick as well.So if you're after a handheld, I'd say go with theBM869S(~$250 shipped). As per the 500,000 count mode, that's just an increase in resolution, not accuracy.Otherwise, a used bench meter would be a better value.

author: janoc
author_rank: Super Contributor
timestamp: October 31, 2016, 06:17:14 pm
content: Quote from: nanofrog on October 31, 2016, 03:58:34 pmI have got my BM869 from TME.eu, good meter and no problem service from TME, so certainly do consider the option. It compares pretty well to the Fluke 87V.

author: Nrkb
author_rank: Contributor
timestamp: October 31, 2016, 11:56:07 pm
content: TME is really nice but i'm in canada so theres a lot of fees from them using UPS or DHL or whatever.Anyway thanks for all the suggestions, i got the Amprobe on amazon from the 4part youtube review i saw it's really good and accurate withing my budget, not like some of the 1000$+ suggestions some said haha just kiddingi wish i could afford that

author: 2N3055
author_rank: Super Contributor
timestamp: November 01, 2016, 12:02:17 am
content: Quote from: Nrkb on October 31, 2016, 11:56:07 pmTheir shipping to Canada is 17.80€ per web site, DHL or UPS... I don't know about customs on your side..

author: retiredcaps
author_rank: Super Contributor
timestamp: November 01, 2016, 12:13:53 am
content: Quote from: Nrkb on October 31, 2016, 11:56:07 pmIf UPS, be prepared to get dinged at least $35 or $40 CDN for customs paper works alone plus Canada Customs GST and PST and duties/taxes. It could easily come out to $60 CDN alone.In addition, if the meter is faulty, sending it back to TME could cost the same amount when you price out a tracking number option.

author: nctnico
author_rank: Super Contributor
timestamp: November 01, 2016, 12:41:02 am
content: AFAIK most handhelds are optimised for measuring 50Hz AC and their accuracy isn't that good either so they are likely not very useful for calibration audio. AFAIK the cheapest option with a reasonable bandwidth (20kHz) and good accuracy is the Vici VC8145 bench model (around $160 on Ebay). The VC8145 has a dB mode for various reference impedances. You have to be careful with the input level though because that affects the accuracy due to the level range limit of the true-rms converters. That is the tradeoff in cheap DMMs: either a limited frequency range or a limited level range for true RMS AC measurements.Oh, and continuity is instant on the VC8145.

author: singapol
author_rank: Frequent Contributor
timestamp: November 01, 2016, 03:45:05 am
content: Quote from: blueskull on October 31, 2016, 02:21:28 amOP is smart to understand the amprobe is same as brymen 857s so I congratulate his wise selection.That said meter is only assured to be in spec. for 1 year only , after that OP is on his own.It's either think philosophically or logically or be a voltnut.