3 DMMs - spot the difference ;) - Page 1
Forum section: electronics / general

author: patb
author_rank: Regular Contributor
timestamp: July 21, 2011, 07:35:44 pm
content: Hi guys,I am not an expert in DMMs, but I spotted very similar DMMs from different manufaturers (see attached images). Am I correct that all 3 below multimeters are actually the same construction inside?Extech MM-560 (http://www.extech.com/instruments/product.asp?catid=48&prodid=283)Amprobe AM-140 TRMS (http://amprobe.com/cgi-bin/pdc/viewprod.cgi?pid=1913&tid=1&type=elec)Brymen BM-857a (http://brymen.com/product-html/cata850a/Bm850as.htm)Amprobe has a little bit different specs, but... I don't know. It looks the same. I didn't check prices, but I know that Brymen is cheaper than for instance Extech (in Poland at least).EDIT: It seems that Amprobe AM-140 TRMS is obsolete now. Current version is AM-140-A, which looks very similar but is black/red.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 21, 2011, 07:51:49 pm
content: Welcome to the wonderful world of rebranding, also known as badge-engineering, also known as OEM, ODM, VAR.

author: ivan747
author_rank: Super Contributor
timestamp: July 21, 2011, 08:00:26 pm
content: The Extech image seems to be retouched

author: patb
author_rank: Regular Contributor
timestamp: July 21, 2011, 08:40:59 pm
content: Quote from: BoredAtWork on July 21, 2011, 07:51:49 pmYay!

author: IanB
author_rank: Super Contributor
timestamp: July 22, 2011, 01:13:06 am
content: It might be that they use the same core DMM chip inside, hence the similar buttons and range switches, but it is still possible that they have different mechanical and electrical construction inside the case. Only by taking them apart and examining the circuit boards could you tell.Since such a meter is more likely to be used as a "lab" meter than an "industrial" meter, the ruggedness and input protection might not matter so much as the accuracy, repeatability and stability over time. Which you still can't tell from looking at them...

author: EEVblog
author_rank: Unknown
timestamp: July 22, 2011, 12:11:09 pm
content: Add the Greenlee to that list by the looks of it:https://www.eevblog.com/forum/index.php?topic=4233.0DM-860Aand the DM-860CDave.

author: firewalker
author_rank: Super Contributor
timestamp: July 22, 2011, 02:15:34 pm
content: Quote from: EEVblog on July 22, 2011, 12:11:09 pmI would like to see a review of those ones. The ExTech one for sure.I have seen such DMMs again. It is not bad that they are using the same mcu. The "secret" is the construction quality and the design effort.Alexander.

author: patb
author_rank: Regular Contributor
timestamp: July 22, 2011, 02:39:53 pm
content: Quote from: EEVblog on July 22, 2011, 12:11:09 pmYeah, probably DM-860C is like Extech MM-570 and Brymen BM-859CFa and Amprobe AM-160 TRMS (note the temperature measurement mode). Crazy!But the good thing is, assuming these are nearly identical, that the prices are different and we may choose.Patryk.

author: ejeffrey
author_rank: Super Contributor
timestamp: July 22, 2011, 03:52:37 pm
content: Quote from: firewalker on July 22, 2011, 02:15:34 pmI don't think these are using the same MCU, I think they are using the same PCB. The enclosure and the display are different for some of them, but the PCBs are at least based off the same original design. That is the only way you would get the range switch and buttons being in exactly the same order. The mechanical design and ruggedness may be somewhat different from one to the next, and that is certainly important, but the internal quality is likely to be the same.It is also common to find lots of meters with almost identical specs that are essentially a copy of the reference schematic from the DMM chip manufacturer, but these are more likely to have layout differences in the buttons, input jacks, and range switch.

author: Extech
author_rank: Contributor
timestamp: July 22, 2011, 05:16:22 pm
content: Sweltering hot greetings from the Extech office in Waltham, Massachusetts. (98°F, 37°C!)Thanks, Patryk for bringing up this question about the similar multimeters. I know that with a market filled with a dizzying array of specs and models, this type of similarity can be confusing. I can speak on behalf of the Extech part of the question with no sugar-coating:The Extech MultiMaster MM560A and MM570A (which also measures temperature and Delta-T) are made through a partnership with Brymen Technology Corporation, one of the brands pictured. We worked with them specifically to introduce the Extech MultiMaster (and more basic MultiPro) models several years ago. Brymen has proven to be a trusted manufacturing partner for quality test instruments that meet Extech standards.We have introduced several new DMM's since then and the MultiMaster models continue to be popular for several reasons: remarkably high accuracy (down to 0.02% on MM570A); tremendous resolution for a handheld meter (500,000 counts), CAT-IV safety rating (!), a rugged design, and a set of functions that are hard to match.Not only are they sensitive enough to work on benchtop electronics testing applications, they are also suitable for measuring a 680 V bus on a distribution panel for example. I would say it is a testament to their quality and manufacturing if Brymen has been enlisted by other DMM brands since our MultiMaster was introduced.I've tried to do a quick apples-to-apples comparison of the models posted here and I would say this first:I can't speak on behalf of other companies to say with authority that they are physically identical or from the same source.But model to model, looking at publicly available specs, if you match the tiers, most of the specs appear very similar or identical.Keep in mind, you're conceivably looking at afamilyof meters--not one meter. For example, Extech offers several models with varying tiers of incrementally more features. Others may do the same. If you include our MM570Ahttp://www.extech.com/mm570a, you're looking at higher specs than some of the models listed in the thread.Other important things to keep in mind that often don't make the apples-to-apples spec checklist have more to do with the company whose name is on the meter:What kind oftech supportis available? Where is it based?How responsive iscustomer support? Where is it located and is it focused on quick and efficient help?What type of in-housequality controlprogram is in place (vs. 3rd party)?Are theyISO9001:2008certified?Do they offer fast-turnaround, in-house calibration services withNIST-traceable certification?Howeasy-to-findare products at local retailers and distributors, plus online sites?Do they keep up with you using asocial networking communityand great forums like EEVBlog?How long have they been around? And how longwillthey be around?I hope that is a helpful reply! Please let me know if you have any other questions.Best,André RebeloExtech InstrumentsPS, If you're looking online for an Extech MM560A or MM570A, keep in mind the newer-gen model has the "A" suffix. There were some board-level updates made over the original generation from a few years ago that improved accuracies in some ranges. And the related software was upgraded as well. I can't say if that is the case with comparable models from other brands.

author: firewalker
author_rank: Super Contributor
timestamp: July 22, 2011, 06:36:20 pm
content: Quote from: ARebelo-Extech on July 22, 2011, 05:16:22 pmI really really like it when companies pay attention to users opinions. ExTech is really doing a very good job at this section. I was almost sure that someone from ExTech would answer!Something somehow irrelevant... What does ExTech thinks of an open hardware/source DMM?https://www.eevblog.com/forum/index.php?topic=3978.0Alexander.

author: patb
author_rank: Regular Contributor
timestamp: July 22, 2011, 07:32:10 pm
content: Hi André,I hope that air conditioning in your office works well. In Poland we finally (after heat wave) have something around 20 deg C.I am happy to see that Extech is taking all of our opinions seriously (you could also take a look at thread about ex430). And congratulations to Dave for the blog and this forum. Finally we can exchange questions/suggestions with gear manufacturers directly. Thumbs up!It is nice to hear than Brymen is trusted manufacturing parter, because I actually own BM-857a DMM.From your post I understand that Brymen and Extech products (560/570 vs 857/859) are actually almost-the-same construction with some minor differences. Now I believe that Dave won't miss those models in his shootout about 500,000 counts multimeters. From my side I can only confirm your words about this construction, although only at the hobbyst level.As for the bullet points.QuoteHaven't tested it, but from your response I think it is actaully quite good.QuoteI'm afraid that you have some issues there. My EX430 stopped working properly after 3 weeks (rotary switch malfunctioning). Dave received EX505 with patched PCB (!). Those models were probably produced in China, so I reckon that the problem is there.QuoteISO tries to create a badge for "quality", but this doesn't work well. I've heard numerous stories how those certificates are granted. Basically perception of those right now is "badge for money". At least here in PL.QuoteProbably important for professional use. Unfortunately, I don't know much about it.QuoteYes, you definitely win here.QuoteHuge thumbs up for you.André, thanks for your post. It is really great to see that you guys at Extech really care about us - customers.Best regards,Patryk.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 22, 2011, 07:35:35 pm
content: Quote from: ARebelo-Extech on July 22, 2011, 05:16:22 pmHi André and welcome.One first tip would be to inform your web design team to correct this (100Vinput protection on all functions)on the web link about the 570A.Regards.kiriakos

author: Bored@Work
author_rank: Super Contributor
timestamp: July 22, 2011, 08:13:10 pm
content: Quote from: ARebelo-Extech on July 22, 2011, 05:16:22 pmHere you blew it.There are so many technical standards available you could have referenced, especially safety standards. And, for example, how Extech not only prints safety marks on their products, but how Extech runs the tests to make sure the products meet the standards required for being allowed to carry such marks.But you chose to come up with the paper-shifters dream, ISO9001. ISO9001 has a pervert definition of "quality". ISO-Quality is when you document it (aka have a "quality management system" in place) and (pretend to) follow the documented procedures. You can document the most abysmal technical quality and procedures and as long as you build the rubbish according to the documentation, or at least make an auditor believe you follow the documentation, you are still compliant. Nothing in ISO9001 demands real technical quality.But while we are at it, did you know that Dave was almost killed by an Extech product, the Extech RC200 tweezer multimeter? And did you know that people were surprised Extech didn't issue a recall? While in the same year Extech recalled other productshttp://www.extech.com/instruments/recall2010.aspNow, how come that dodgy RC200s with that defect are still in the hands of unsuspecting users? Does your quality management system allows this?QuotePlease see above.

author: Unknown
author_rank: Unknown
timestamp: July 23, 2011, 12:07:00 am
content: Quote from: BoredAtWork on July 22, 2011, 08:13:10 pmOnly if the procedure guarantees a consistent current flowing through the heart of the owner. And if it contains provision for monitoring said current.

author: Extech
author_rank: Contributor
timestamp: July 25, 2011, 12:19:18 pm
content: Quote from: patb on July 22, 2011, 07:32:10 pmPatryk,Thanks for your positive words. I'm sorry to hear about your experience with that EX430. We only have one chance to make a first impression and it's a disappointment when we falter in that effort. I am _very_ well aware of the patched PCB EX505. It wasn't fit for human consumption and was an embarrassment for us. The experience, and the constructive feedback from Dave offered many lessons to be learned for us. In fact, Dave's video made its way back to the manufacturing floor.I appreciate your feedback on the ISO "badge." I'm surprised by the comments about this. Internally, we take it very seriously, and it is something everyone in the company contributes to in order to make it a success. I wish we could say we just "bought it" but the disruptive experience would contradict that.Thanks again, Patryk!

author: Extech
author_rank: Contributor
timestamp: July 25, 2011, 01:06:59 pm
content: Quote from: Kiriakos-GR on July 22, 2011, 07:35:35 pmWhat theNice catch, Sir.Web team has been notified. Look for the edit later today.Thank you and!Update: Done!

author: FreeThinker
author_rank: Frequent Contributor
timestamp: July 25, 2011, 01:49:42 pm
content: To put 'Badge Engineering' into perspective a freind of mine who ran a TV repair shop (remember those?) once told me that nearly all tv chassis were based on three or four manufactures boards (Phillips was one I seem to recall). The TV makers designed the case around the standard chassis and crt and most end products ended up very similar. This is why they could be repaired. Now each tends to be a custom part and support/repairs a thing of the past. Progress!!

author: Extech
author_rank: Contributor
timestamp: July 25, 2011, 02:26:06 pm
content: Quote from: BoredAtWork on July 22, 2011, 08:13:10 pmHi there,Thanks for taking the time to ask these questions.Wow, as I mentioned to Patryk, I did not realize there was so much "love" for ISO9001. We do take it very seriously as an organization and devote a lot of resources in every department to show theactionand thedoingthat is behind the paperwork. I understand there is disagreement about what it really recognizes. If there is any real, tangible positive for Extech going through it, my hope is that we operate as a better company for it, to our customers' benefit.You're right, that's a great point that there are a lot of other noteworthy standards we follow, that I take for granted. When I look at other brands that don't follow safety mark standards, to borrow your example, I am reminded that what we do is not always the norm.About your other discussion, I am very well aware of Dave's RC200 experience. As Dave will attest, I was in very close direct communication with him immediately after he posted the video and was ready to board a plane to meet with him. In light of what transpired, Dave was a real gentleman in generously keeping the lines of constructive communication open. We listened attentively not only to what took place but also to all of his points about what was wrong with the product. Believe me, Dave's inimitable voice exclaiming "heap o' sh!t" echoed loudly around here!What was the result? The new product was stopped, promptly re-designed in direct response to Dave's criticism and released with those changes. Not only he did he make a direct impact on what we were doing, we did not sit on his feedback. We ran with it, implementing and testing it so thatwhenthe productwasreleased -- still on time -- it satisfied our most vocal -- and welcome --critic.Regarding the recall comparison, when I had sent the RC200 to Dave, it was an all-new product for Extech. We originally intended to send him an RC100 as a precursor to the LCR meter reviews, but I had just gotten my paws on an RC200 and wanted to share the new product. There were literally a handful of RC200s here and they hadn't yet entered distribution. We basically stopped it, re-tooled, and rolled out the corrected RC200 in record time.I don't think ISO recognizes that type of real-time responsiveness but hopefully the RC200 back story is helpful to EEVBlog readers here. Thanks again for the opportunity to address that.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 25, 2011, 05:42:48 pm
content: Quote from: ARebelo-Extech on July 25, 2011, 02:26:06 pmSomething does not add up here. On February 16, 2010 you had a press releasehttp://www.extech.com/testequipment/press.asp?pressid=02162010The press release contains (emphasis by me):QuoteThat sounds like you had it in distribution since February. Dave's video is from June 14, 2010That is four month later. And you say there weren't any in distribution at the time you became aware of the issue, which presumably was in June, too?

author: patb
author_rank: Regular Contributor
timestamp: July 25, 2011, 06:52:07 pm
content: I've just checked prices:Extech MM560 - 260 USD (this is not version with NIST cert!)Brymen BM857A - 145 USD (not available in US; I wonder why?)Amprobe AM-140-A - 170 USDAndré, it seems that your company is charging about 100 USD only for your logo.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 25, 2011, 06:58:03 pm
content: Quote from: patb on July 25, 2011, 06:52:07 pmAnd their ISO9001 certification

author: Extech
author_rank: Contributor
timestamp: July 25, 2011, 07:05:01 pm
content: Quote from: BoredAtWork on July 25, 2011, 05:42:48 pmOh, I know about the timing, I wrote and scheduled that announcement myself, including the template language you excerpted. And I sent the meter to Dave in May. Unfortunately, it's probably not the first or last product whose announcement went out by us -- or by others -- before it was available.

author: Extech
author_rank: Contributor
timestamp: July 25, 2011, 08:31:50 pm
content: Quote from: patb on July 25, 2011, 06:52:07 pmYes, the logo is printed with unobtanium, very hard to come by.Seriously though, thanks for the price comparison, Patryk. I need to verify if those are apples-to-apples models (at least 4 tiers in the model family) but I will share your comments here at Extech!

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 25, 2011, 11:33:16 pm
content: Hi AndréAt the page of the MM570A there is one description saying :Filtered frequency function with adjustable trigger levelsfor variable speed motor drives and high voltage applications.Do you have at Extech any technical document explaining in depth the suggested Trigger levels for its one situation ?PLC sampling rate VS trigger or frequency?Thanks.

author: PetrosA
author_rank: Frequent Contributor
timestamp: July 25, 2011, 11:35:08 pm
content: Andre, I think your responses are very respectable and it's good to see you putting your neck out for Extech. It shows that there's a willingness to accept accountability that means a lot to me as a customer. My next piece of test gear will most likely be a CT70 - I just need to get a few other priorities taken care of first

author: EEVblog
author_rank: Unknown
timestamp: July 26, 2011, 12:31:44 am
content: Quote from: ARebelo-Extech on July 25, 2011, 02:26:06 pmYes, I was impressed that you offered to fly all the way to Oz and come into the lab and explain on camera.With hindsight I probably should have taken you up on that offer and made you sit through that horrible 14 hour flight as payback!Dave.

author: PetrosA
author_rank: Frequent Contributor
timestamp: July 26, 2011, 12:57:49 am
content: BTW, it looks like planetextech.com has been hacked

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 26, 2011, 12:08:44 pm
content: Quote from: EEVblog on July 26, 2011, 12:31:44 amLOLI would not mind to visit the Oz land, and have a beer with the destroyer of the the Extech products !

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: July 26, 2011, 12:11:58 pm
content: Quote from: PetrosA on July 26, 2011, 12:57:49 amNop it works as usual.

author: Extech
author_rank: Contributor
timestamp: July 26, 2011, 12:48:24 pm
content: Quote from: PetrosA on July 25, 2011, 11:35:08 pmThanks, Peter! The CT70 has been getting a lot of great feedback. It can reduce time analyzing outlet conditions to just a few seconds. A great timesaver.

author: Extech
author_rank: Contributor
timestamp: July 26, 2011, 12:55:28 pm
content: Quote from: EEVblog on July 26, 2011, 12:31:44 amNow boarding Purgatory Airlines...