Amprobe AM-140-A DMM imprecise? - Page 1
Forum section: electronics / general

author: Termo
author_rank: Newbie
timestamp: March 25, 2012, 12:05:58 am
content: Hey guys,I'm looking to buy a half-decent DMM, and I require it to be pretty accurate when it comes to VDC.I find it extremely difficult to wrap my head around the concept of the AM-140-A outperforming all the handheld Fluke DMMs, the 87 V included, when it comes to accuracy, as stated in the respective data sheets.I mean... really?TheAM-140-A is dirt-cheap(and not even Amprobe's flagship DMM) in comparison to even the Fluke 175, while the former crushes the latter in the features department, overwhelmingly.So, I ask:1. Does the Amprobe AM-140-A really live up to its accuracy specifications(especially the 0.03% + 2 LSD on VDC)?2. If any of you guys own the Amprobe AM-140-A DMM and have done some comparisons of known parameters and the respective AM-140-A measurement readouts, please do share your findings with all of the folks reading this thread.3. When it comes to Fluke DMMs, does one only pay for the brand name, warranty, and abuse tolerance, or is there some more value to them than that (apart from the wow factor and bragging rights, of course)?4. Where is the catch with the Amprobe AM-140-A, if there is one?Thank you for any and all of your input.Yours faithfullyTermo

author: Spawn
author_rank: Frequent Contributor
timestamp: March 25, 2012, 12:25:21 am
content: Hi Termo, first of all welcome to the forumsQuote from: Termo on March 25, 2012, 12:05:58 amFor your third question watch this and see how Dave try his best to destroy a Fluke and you would understand why we want a Fluke, we definitely don’t pay for the brand name, as prof electrics engineer I can tell you I used a lot different brands, there are not much mms out there which can beat Flukes durability.I got couple Flukes and one Gossen and they are really worth their money, some of them are really old ones.See this:Check Dave’s vids, he got couple blogs explaining what you get for your money.

author: Termo
author_rank: Newbie
timestamp: March 25, 2012, 12:39:05 am
content: Quote from: Spawn on March 25, 2012, 12:25:21 amThank you and will do! How does your Gossen stack up to the Flukes? What model is it? Going to watch the video you linked, now. Thanks again!

author: IanB
author_rank: Super Contributor
timestamp: March 25, 2012, 12:44:57 am
content: I haven't tested one, but it isn't "hard" to get good DC accuracy in a meter. So it probably does live up to its specs when new.But what about temperature stability? Accuracy retention over time?Compared to a Fluke, what about physical robustness? Overload protection? Safety when overloaded? Warranty? Ease of calibration and availability of a calibration certificate?Anyone can ask for an "accurate" meter, but high accuracy is not top of the list for most purchasers.

author: FenderBender
author_rank: Super Contributor
timestamp: March 25, 2012, 12:48:28 am
content: I have an AM-270 which is actually quite similar hardware wise. I think the 140 may have some upgraded ADC chips/software etc. Really good meter. Very high quality and yes the accuracy is good. Can't tell you if mine is spot-on since I don't have super precise equipment, but it seems to be in spec from my view.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 25, 2012, 12:55:41 am
content: Quote from: Termo on March 25, 2012, 12:39:05 amA side note, actually a important one I think, Amprobe is owned by Fluke (same owner) So mentioned specs should be accurate.I don’t own any Amprobe when it comes to decent size one, but I own a pocket size Amprobe DM78C and to be honest it’s continuity test is getting me crazy, it takes a good second to beep it’s not instant as one of my 5 dollar pocket mm, and that’s not such a good thing because while you are on field and want to test continuity, you don’t want to go to grab your bigger mm and just use your pocket mm.I got a Gossen Metrawatt – Metra Hit 23S, and compared to a Fluke there are not much differences and if I must be honest my Fluke 77 IV feels more decent went it comes to durability.But Gossen is still saver because of it is mechanical lead protections, you get a warning beep in a Fluke but in a noisy environment you just don’t hear that.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 25, 2012, 01:13:19 am
content: Oh! when you finish watching that video also take a look at Dave’s 100 dollar range multimeter video.He compares 6 multimeters there, while you start watching grab some beer and something to eat because it’s in two parts and 100 minutes in totalI enjoyed watching this while back when it was posted

author: Termo
author_rank: Newbie
timestamp: March 25, 2012, 01:29:25 am
content: Quote from: IanB on March 25, 2012, 12:44:57 amI didn't get the feeling (I could be wrong, of course) that the AM-140-A was a sub-par product (likes ofor)Its CAT rating seems to be pretty decent (IV/600V + III/1000V; haven't seen or heard of better on a handheld, myself), to, if nothing else, cover the safety concerns you pointed out.So, please do share your opinion on the Amprobe brand, in general, and the AM-140-A model, specifically, if you have one to express.Thank you.

author: Termo
author_rank: Newbie
timestamp: March 25, 2012, 01:34:09 am
content: Quote from: Spawn on March 25, 2012, 12:55:41 amDo you think ownership matters that much, when it comes to these things?I guess there's a reason why Amprobe products form a separate brand from Fluke.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 25, 2012, 01:47:59 am
content: Well let me put it this way, of course it does little bit matter (in my opinion). I think such a company as Fluke don’t want a company making crap meter under their flags, I don’t want to brake a forum war with start calling other brands which can do better compared to a Amprobe in that price range.I don’t want you to think I am a Fluke fan or something, I also own two Voltcraft dmm’s because I needed a couple futures which where to expensive on a Fluke.OT: Lol, while I was writing Voltcraft I accidently typed Voltcrap, I don’t know if it was a sign from above but I sure like the Volcraft’s for measurements I use.

author: IanB
author_rank: Super Contributor
timestamp: March 25, 2012, 03:03:59 am
content: Quote from: Termo on March 25, 2012, 01:29:25 amFeelings are a really objective way of judging things of course.QuoteA CAT rating is only what is printed on the meter. It says nothing about how that rating stands up to rigorous testing.QuoteSo you're just being tiresome and silly?Opinion #1: The Amprobe is every bit as good as a Fluke. Don't waste your money on the expensive brand image.Opinion #2: The Ambrobe costs much less than the Fluke because it it is less good in several ways. You should choose your requirements carefully and pick the appropriate tool for your needs.There, pick the opinion you prefer.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 25, 2012, 04:05:05 am
content: Quote from: Termo on March 25, 2012, 12:05:58 amIf you require accurate VDC measurements, have you considered a bench multimeter assuming you don't need the mobility of a handheld?

author: Termo
author_rank: Newbie
timestamp: March 25, 2012, 04:21:35 am
content: Quote from: retiredcaps on March 25, 2012, 04:05:05 amYes, I have.Do you have any particular brand/model in mind one can put their confidence in to be accurate, reliable (keeping its spec, over the long haul), and not totally break the bank?Thank you very much.

author: Termo
author_rank: Newbie
timestamp: March 25, 2012, 04:28:31 am
content: Quote from: IanB on March 25, 2012, 03:03:59 amQuoteNo need to be patronizingly sarcastic, is there? I used the expression as a figure of speech. I have to start somewhere when deciding on anything. One could say that Amprobe is a house brand, recognized, even Dave considers it a "big brand name", its specs are up there, and it's relatively pricey, too, which together with the aforementioned makes me lean towards my "feeling" that the unit shouldn't be sub-par.QuoteI'm pretty sure that the IEC standards count for SOMETHING, and one can't just print out any horse manure on the DMM, otherwise every meter would have had CAT IV 1000V/600V on it.QuoteThe thing is, right, the Fluke brand has such amplifying resonance attached to it that one just can't argue its "gold standard" status that's recognized industry-wide by a plethora of professionals. I am aware that the default scientific stance should be skepticism, but sometimes, theories have axioms; this seems to be at work here, as well.If my life depended on it (funny expression, when it comes to DMMs), then... uhm... nevermind, scratch that.Right, whenever I "solemnly decide" to buy a Fluke, I can't help myself to not be upsold by them,every time,because even though the "entry price line" is high, subsequent price-performance incremental trade-offs make me think that a psychologist designed their pricing policy.Ultimately, I find myself reviewing the 87 V manual and data sheet (time and time again), only to realize that the price got inflated, incredibly, from the reference Amprobe model(s).What usually follows is the selection process restart, all the way from the beginning.Summa summarum, I'm grateful for your valued input, IanB.Thanks!

author: IanB
author_rank: Super Contributor
timestamp: March 25, 2012, 04:39:49 am
content: Here's the thing. I don't own a Fluke. They are too expensive for what I need.I am, however, a bit tempted by the Amprobe AM-140-A now you have brought it to my attention. It is a nice looking meter that I was not aware of before.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 25, 2012, 05:42:55 am
content: Quote from: Termo on March 25, 2012, 04:21:35 amI have done a lot of research into handheld multimeters and I NEVER thought I would end up buying 6 Flukes when I probably NEED 2 multimeters from any reputable maker, but they are all used and I got them at really good prices (it required a lot of patience).I have NOT done any research into bench multimeters and if you do not mind buying used, here might be a representative type of deal you can get for about $200 USD. BTW, I have no afflilation with the seller, but I know someone who bought a Fluke 87V from him and was quite pleased with the purchase. This is just a quick sample.http://www.ebay.com/itm/120884000308Someone more qualified may be able to tell you if the above is a good deal or not. I'm sure Agilent/HP make comparable models that you can get in the used market for about $200 USD.Page 1-2 shows the VDC specs athttp://assets.fluke.com/manuals/8840A___imeng0300.pdfAFAIK, no handheld multimeter even comes close to those specs.Obviously with used equipment, there are no guarantees that it has held calibration or was even calibrately annually so caveat emptor. Buying new, however, does not guarantee that the multimeter is properly calibrated as there have been a couple of reports from people on this forum that brand new handheld multimeters (Uni-T and Klien Tools) were not calibrated properly from the assembly line/factory.

author: G7PSK
author_rank: Super Contributor
timestamp: March 25, 2012, 09:42:05 am
content: I have an Amprobe AM240, had it since January this year and it has proved so far to be fairly good, well its not broken or given an incorrect reading and has stood up to some rough use being exposed to things like diesel fuel and grinding dust, welding sparks etc, I dont expect that it will last as long as the AVO Panclimatic I also use that has had over 30 years of service in such conditions I would not expect that a fluke would survive either, For the time being I use both together. The only reason I did not buy the Fluke, You pick up a nice bright yellow plastic object with hands covered in a mixture of diesel and engine oil, Its ruined for ever.

author: T4P
author_rank: Super Contributor
timestamp: March 25, 2012, 10:20:35 am
content: It's just ... How my Wavetek DM5XL had such a big history , of turning into the XP series then being merged to Amprobe by fluke .

author: retiredcaps
author_rank: Super Contributor
timestamp: March 26, 2012, 04:40:20 am
content: Another possible decent deal on bench meter?http://www.teknetelectronics.com/DataSheet/FLUKE/FLUKE_8860a44722.pdfhttp://www.ebay.com/itm/330708343750Seller seems to deal with a lot of name brand test and measurement equipment too.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 26, 2012, 04:48:59 am
content: I cant see the other equipments, because he doesnt ship to The Netherlands.I just dont hope it is same list as this one here:https://www.eevblog.com/forum/buysellwanted/equipment-for-sale/

author: saturation
author_rank: Super Contributor
timestamp: March 26, 2012, 09:11:04 pm
content: Reputable manufacturers tend to report the accuracy of their T&M gear as worse case scenario specs.There is no standard, or guideline, requiring specs to be reported in a consistent comparable way and consequences if the spec sheet is misrepresented. So its important to be able to do a performance test on the DMM, to check it lives up to specs and be able to return it to the seller if it doesn't.One test I did was to put the Fluke 87V in the freezer and hot sun for an hour. I found it held room temp accuracy even at those extremes, from 1-30VDC. The specs have a derating curve for accuracy based on ambient temperature, but I found it barely needed the correction.However, if you're looking mostly to do VDC in a lab situation, and you know what your accuracy % need be, maybe this Amprobe is what you need and the toughness associated with the Fluke isn't what you need to pay for. Even on average, a particular meter may win out against others, you maybe concerned with one function more than others.In this cumulative graph in the eevblog archives, you can see the 50,000 count Agilent 1252a is the best overall accuracy DMM, but it has specific weakness compared to the 87V, in resistance and frequency. The bars are percentage deviation from a standard value, compared against a calibrated HP 3456a 6.5 digit DVM. Shorter is better.

author: FenderBender
author_rank: Super Contributor
timestamp: March 28, 2012, 01:17:38 am
content: Here guys. I almost forgot about this. I made a thread when I was buying my AM-270 looking for teardowns/reviews of it. Lanman was kind enough to shoot some pics of hisAM-140.https://www.eevblog.com/forum/general-chat/anybody-have-teardowns-of-newer-amprobe-dmms/It's pretty good inside, especially for the price.And then here's my review/teardown of the AM-270 which is similar in form and function:https://www.eevblog.com/forum/product-reviews-photos-and-discussion/teardown-amprobe-am-270-digital-multimeter/