6.5 digit DMM questions 8845A vs. 34401A vs. Siglent - Page 1
Forum section: electronics / testgear

author: Jester
author_rank: Frequent Contributor
timestamp: November 28, 2021, 08:55:00 pm
content: I’m looking for another used 6.5 digit DMM…….EBay prices for the 8845A seem about $200 higher than for the 34401A. For anyone that uses both meters regularly is the Fluke worth the $200+ premium?I’m also wondering if anyone has used both the 34401A as well as one of the new 6.5 digit Siglent meters, is there anything you don’t like about the Siglent?

author: bdunham7
author_rank: Super Contributor
timestamp: November 28, 2021, 09:51:21 pm
content: Quote from: Jester on November 28, 2021, 08:55:00 pmI have the 8846A and the 34401A and while the 8846A has a few additional features over the 8845A (1G resistance, capacitance), both of them are much easier to use than the deep-menu 34401A. Almost anything can be conjured up in 2 button pushes. The selectable diode test (5V/10V) and current (1mA/0.1mA), selectable continuity threshold (1/10/100/1000R) and USB/LAN connectivity are probably the main advantages over the 34401A for me. The only downside to the 8845A/8846A in the used market is that you have to be sure to get a good, non-abused unit. They don't take kindly to rough physical treatment and the VFD display will burn a bit if you leave it on full brightness for years on end.The 34401A prices have skyrocketed recently, I don't know about the Flukes. When I got mine, there was about a $1000 price premium for the 8846A and I still think it was worth it.

author: MadTux
author_rank: Frequent Contributor
timestamp: November 28, 2021, 11:50:00 pm
content: Fluke 8845A/8846A internal design is garbage. Mechanical design, reliability and repairability isn't great either.Display and it's replacement, if it fails, could be quite horrible as well.100MOhm seems standard for half sized DMMs, except Keithley 2001/2002 or 8846A.For full size DMMs, 1G seems standard in HP instruments (3455A/3456A/3458A)Good diode and continuity is much more useful IRL, which is unfortunately lacking in most full sized DMMs as well as Keithley 2001/2002Keithley 2000/2015/2010 and HP 34401A are build much nicer, IMO. For pure metrology in 1/2 size, Keithley 2001/2002 is best.

author: mawyatt
author_rank: Super Contributor
timestamp: November 29, 2021, 01:02:32 am
content: We have a few weeks old DMM6500, few months old SDM3065X, a 2 Year old KS34465A, and much much older AG34401A and a even older HP34401A. Of all these my least favorite is the SDM3065X, and most favorite is the DMM6500, even preferring it over the otherwise excellent KS34465A.The large display and touch screen graphics just place the DMM6500 in another level of user experience, it has become our "goto" DMM for most usages.Another thing to consider is if the DMM has back terminals. These have already proven useful in that we hang a thermistor (or thermocouple) off the back terminals of the KS34465A and DMM6500 to read ambient or an instrument temperature, and don't have to disconnect what's connected to the DMM front. Just push a couple buttons and you can read or graph the temperature, and another couple bottom pushes and you are back to where you startedBest,

author: bdunham7
author_rank: Super Contributor
timestamp: November 29, 2021, 01:49:29 am
content: Quote from: MadTux on November 28, 2021, 11:50:00 pmI'd say maybe a bit odd and hard to understand, not garbage. Your other points are more or less true, which is why I would only buy one new or mint and then treat it very kindly. And probably not use the front/rear switch too much, although that is actually fixable if it is damaged. It's definitely not a model you buy as a fixer-upper like many earlier types.However, where the 8846A excels is......measuring stuff! Well, except for certain current ranges where it embarrasses itself a tiny bit. But for everything else, it exceeds all of those other meters in multiple areas that are important to me, at least. Somebody just posted about their 34465A not measuring 175uVAC. I often need to measure ~1000VAC, the 34465A can't do that either. The 8846A does both. YMMV and everyone's needs are different.

author: dorkshoei
author_rank: Frequent Contributor
timestamp: November 29, 2021, 02:26:41 am
content: One thing possibly worth bearing in mind is that 34401a parts such as VFDs, handles, bumpers etc have been reproduced and are available inexpensively from China. You need to be careful (with all Chinese stuff) but I bought two of the Samsung marked clone VFDs and they work great. I put them away in my parts stash in case I ever need them.Agree that the HP deep menus are not that user friendly.

author: bdunham7
author_rank: Super Contributor
timestamp: November 29, 2021, 02:32:09 am
content: Quote from: dorkshoei on November 29, 2021, 02:26:41 amIf I had to use one daily, I'd make a laminated pull-out menu!

author: dorkshoei
author_rank: Frequent Contributor
timestamp: November 29, 2021, 02:51:28 am
content: I have a34401a for salein case it interests the OP

author: HighVoltage
author_rank: Super Contributor
timestamp: November 29, 2021, 09:13:04 am
content: I bought a 8845A and a 8846A many years ago to fix them. But since parts were not available it was near impossible. I got them working and used them for a while, before I sold them both.The 34401A is much more straight forward to me and parts are available.

author: Zucca
author_rank: Unknown
timestamp: November 29, 2021, 12:57:01 pm
content: Quote from: HighVoltage on November 29, 2021, 09:13:04 am++++10000 time this, schematics are also available. For me 34401A is the best!VFD brightness problem? There is aquicksolution.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 29, 2021, 03:22:55 pm
content: the 34401a is a class of its own, schematics and many parts are availableConnect it to a pc with some logging software(s) links found here and it get hard to beatSure some meters have more functions, But personally i would avoid the flukes ones, seen too many problems and scarse parts availability, the Tektronix models seems to have better help in some case(s).For others brands like siglent and others, slowly they get better over time with some good eevblog members here

author: tooki
author_rank: Super Contributor
timestamp: November 29, 2021, 09:12:36 pm
content: Quote from: MadTux on November 28, 2021, 11:50:00 pmAgreed. I have a Keithley 2015 and it’s a joy to use. (Including superb continuity and diode modes.)