A dream came true Today34401A Digital Multimeter, 6½ Digit DMM - Page 1
Forum section: electronics / testgear

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 20, 2023, 02:53:10 pm
content: A dream came true Today in perfect conditionHP 34401A Digital Multimeter, 6½ Digit DMM

author: Miti
author_rank: Super Contributor
timestamp: February 20, 2023, 03:22:04 pm
content: Are you sure it is 34410 and not 34401? Congrats anyway!

author: coromonadalix
author_rank: Super Contributor
timestamp: February 20, 2023, 03:23:33 pm
content: LOL it is an 34401a not a 34410a huge difference loll

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 20, 2023, 03:54:10 pm
content: Quote from: Miti on February 20, 2023, 03:22:04 pmSorry spelling mistake, it's from the excitementI have been looking for this device for a long timeA friend sold it to me today for less than $200

author: coromonadalix
author_rank: Super Contributor
timestamp: February 20, 2023, 04:00:09 pm
content: good deal if it works ok

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 20, 2023, 04:03:36 pm
content: Quote from: coromonadalix on February 20, 2023, 04:00:09 pmwork perfect no erorrspass all test

author: Miti
author_rank: Super Contributor
timestamp: February 20, 2023, 04:37:18 pm
content: Quote from: DavidAzulay5000 on February 20, 2023, 03:54:10 pmI totally get it. I bought one from a colleague for 150 CAD and I’m thinking of buying the second one for the same price. I can’t find a reason not to.

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 21, 2023, 04:53:27 am
content: Quote from: Miti on February 20, 2023, 04:37:18 pm.

author: Swake
author_rank: Frequent Contributor
timestamp: February 21, 2023, 12:57:09 pm
content: These things go 3x that price on this continent.

author: J-R
author_rank: Super Contributor
timestamp: February 22, 2023, 01:39:22 am
content: I don't think the friends-pricing is valid for comparisons!In my opinion, the 34401A is mostly good for accuracy & stability, but to capitalize on that you need to have it calibrated. Usability is becoming a bit outdated compared to the new stuff on the market Even something as simple as Min/Max is a pain in the neck.

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 22, 2023, 03:41:47 am
content: Quote from: J-R on February 22, 2023, 01:39:22 amAmazing deviceIn terms of calibrationI tested it compared to myQuadtech 1659 RLC DigiBridgeHe is my standard in terms of accuracyIndeed all the resistance of the resistors exactlyFrom 5 milli ohms to 100 mega ohmsThe only thing I did to 34401AThis is a short calibrationI was surprised that the milliohm resistance measurement was accurate even with 2 wires

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: February 22, 2023, 06:16:13 am
content: Then you are assuming the Quadtech is your reference standard, when did you last check its calibration?The 34401A is capable of better than 0.01% accuracy in resistance measurement, which far exceeds the Quadtech spec of 0.1%. So while what you do can verify whether it is in the ballpark, it is far from the calibration 3-R suggested. As the full calibration also check on other functions beyond resistance as well.However, many 34401A hold its accuracy well, perhaps that’s all you need, and that is perfectly acceptable. But if you need a 6.5 digit meter for high precision and accuracy, then I agree with 3-R that a full calibration is a good investment.I think annual calibration may be excessive for most hobbyists except the volt nuts, I personally would send a used meter for calibration, so i know I can trust its reading. Especially if it has not been calibrated for a few years.In any event, congratulations on your new meter. I have a couple, I love their silent operation and fast boot time. But if you need to see MIN-MAX, then I think newer meters definitely have an advantage.Enjoy your new meter. Outside of a calibration,I would also suggest a new VFD if you want the ultimate readability.

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 22, 2023, 06:36:04 am
content: Quote from: NoisyBoy on February 22, 2023, 06:16:13 amthis is all i need dont use MIN-MAX

author: coromonadalix
author_rank: Super Contributor
timestamp: February 22, 2023, 11:16:51 am
content: i had some of my 3x 34401a meters checked and 2 of them ended being calibrated, but the cal facility said they where on par / within the specs 10-15 years later ....i recapped 2 of them, and 1 of them had an clone vfd installed in it ........now upped the game with an 34410a, who got a new cloned vfd toooyou have some software here on eevblog if you want to do some logging ....

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 22, 2023, 12:31:57 pm
content: Quote from: coromonadalix on February 22, 2023, 11:16:51 amI know the softwareLater I will install it on one of my computers that has a GPIB connection.I am very pleased with the purchaseUsually all my measuring equipment I bought broken and repaired and calibrated after that.This is one of the only devices I've purchased that is completely working.He had another 34401A that I could have purchased much cheaper because it had a problem measuring resistor values less than 2 ohms and I did not purchase it even though it is very easy to fix it in the future I might purchase it as well because I really liked the performance of the 34401A .I tested the 34401A todayin a 4 wire connectionfor measuring resistancesof my VISHAY precision resistor collection0.01%And all the measurements were exactI'm going to use it mostly for measuring short circuits.That's why the milliohm resistor measurements were most important to meOn a daily basis I use my Quadtech 1659 RLC DigiBridge projectwhich is an amazing measuring device .Its only problem is that the measurements are made on the 4-wire Digibridge fixture connector on the deviceThat means to measure anything you have to connect the component directly to 1659Do you know how pleased I was that the 34401AGave me the same results as the 1659that the 1659 I calibrated.It is very easy to calibrate, you only need 4 precision resistors with specific values24.895 ohms and 15 ppm374.06 ohm 5ppm5.9581 kilohms 22ppm94.986 kilohms 280ppm

author: J-R
author_rank: Super Contributor
timestamp: February 22, 2023, 10:26:59 pm
content: Totally understand if you only need certain functions and can also test the 34401A to verify it is accurate in those areas. I have a DMM I'm debating getting calibrated, but have mostly been just using it for DC 0-10V, so...The calibration data printout for my 34401A has a couple hundred data points. An older device that has stabilized combined with at least a somewhat recent calibration + data is very nice to have. It builds trust!I recently picked up a new DMM with both the factory calibration and then a 3rd party calibration only a few months later. The 3rd party didn't do any adjustments, just provided the data printout. Well, that thing had drifted enough that the last digit is not really even worth looking at. But still in spec. And from a daily usability perspective, it's far better than the 34401A.

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 24, 2023, 12:15:17 pm
content: HP 34401A after zero calibration on all the RangesResistor testing on some of my vishay precision resistor collection0.05 percent0.01 percent2500 ohm10 Kohm5 Kohm125 Kohm1 ohm100 milliohmEtc. etcStarting with resistors 5 milliohm ceramic resistorsUp to 100 mega ohm 1 percent resistors

author: Wade2019
author_rank: Contributor
timestamp: February 24, 2023, 02:14:56 pm
content: Congratulations on owning the 34401A, which is the representative of the multimeter，Although I own three 34401A and one 34410, I am still very excited to meet 34401 for the first time

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 24, 2023, 06:04:25 pm
content: Quote from: Wade2019 on February 24, 2023, 02:14:56 pmi have 4 DMMQuadtech 1659 RLC DigiBridgeHP 34401Akeithley 197A autoranging microvolt dmmFLUKE 87

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: February 25, 2023, 04:59:58 pm
content: In order to check the accuracy of measuring DC voltagesI built a precision voltage reference 5 voltBased on the linear technologyLT6657AHMS8-5Accuracy of 0.1 percent in regulationPPM 0.5The measurement voltage 5.000.73 volts.Later I will build some moreI have too many V REFTo choose from my collection.LTZ1000LM399LT1021 5V 7V 10VTL1634 1.25VLT6657 1.25V 2.5V 3V 5VLT6658And lots of other models.I usually dont like to use them because I like to collect Linear Technology components.Some people collect stampsI collect components.I have about 20 models of their voltage reference

author: PartialDischarge
author_rank: Super Contributor
timestamp: February 25, 2023, 05:19:02 pm
content: Quote from: coromonadalix on February 22, 2023, 11:16:51 amSame, I have a 34401 not calibrated in probably 15 years, checked it with a new DMM6500 and they only differ a bit in the last digit

author: Fungus
author_rank: Super Contributor
timestamp: February 25, 2023, 08:11:08 pm
content: Quote from: PartialDischarge on February 25, 2023, 05:19:02 pmIt's almost as if they were designed for that...

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: March 01, 2023, 08:08:44 am
content: Perfect 10 10.000.00VAnother precision volt reference I builtBased on the Linar Technology ICLT1021bch-10Exactly 10.000.00 Vhttps://www.youtube.com/shorts/Tx1SPPJ5NDI

author: MathWizard
author_rank: Super Contributor
timestamp: March 02, 2023, 05:20:07 pm
content: Quote from: Swake on February 21, 2023, 12:57:09 pmYeah thats a great price, they never go that low on ebay. I think when I got my SDM3065X, all the similar used 34xxx and Keithley's were about the same price, and more. I have no regets the 3065x is great for me, but someday I'd like to see the difference, the top brands make.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: March 02, 2023, 05:38:03 pm
content: You would not want to compare a modern meter UI and display against a vintage meter like a 34401A, when you do your comparison, you should do it against a 34461A. It is not fair to compare a 30+ year old design to a modern equipment.While I love the quiet operation of the 34401A, quick boot time, and stability, it is no match with modern meters without logging its output to the PC. So if you are looking at capturing and displaying more than a single point of of measurement, or trying to see trends, or trying to get dual displays such as voltage and frequency, your life would be so much easier with a modern meter.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 02, 2023, 05:44:40 pm
content: you have some software(s) who will give this old veteran life extension lolll

author: jerryk1234
author_rank: Newbie
timestamp: May 28, 2023, 02:30:09 pm
content: I just got one of these yesterday. Normal Ebay price. What a gorgeous meter! The sixth digit is very slightly brighter than the rest. I ordered a new display. Not so much because it's dim, rather to have a spare 10 years down the road. Out of the box, it agrees closely with my Fluke 87V. That's good enough for me; my repair and experimentation activities don't require extreme accuracy.

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: June 07, 2023, 06:59:21 am
content: Testing 4 wire kevin sens cable thet I builtwith my HP 34401Awith power resistor 10 milliohmspot on

author: nukie
author_rank: Frequent Contributor
timestamp: June 24, 2023, 09:57:22 am
content: The first stop after I fixed all my used 34401A is the cal lab. Even just simple capacitor refresh. You never know what the equipment went through and they could have done repairs to the devices. Soldering can change alot of things especially with these precision equipment.I have done some repairs to a few 34401A and I find even replacing the tantalum caps near the opamps pins can sometimes throw the calibration off the charts.If you are certain that your equipment is good and want extra assurance you can always rent another 34401A from a reputable test equipment hire. They usually have yearly calibration done on them. If you are lucky it could be done recently. Then you can compare your equipment with the rented dmm.

author: deepfryed
author_rank: Unknown
timestamp: July 05, 2023, 01:05:05 am
content: I recently acquired one of these in good condition, but cost a fair bit more though - closer to A$650It does seem to agree with the precision resistor (0.005%, 0.2ppm/c) and reference (max6350 without trimming, 0.02%, 1ppm/c) I have (not calibrated), but as people have said can't be sure until it's calibrated. I'm not sure if it's purely coincidence or both the reference and resistor have the same error as the DMMThe DMM cal menu says it was last calibrated in 1996, again don't know if people really update it.I'd like to double check the "standards" I have if possible but don't want to spend another $200 on calibration / adjustment! Is there a metrology group in Melbourne ?

author: deepfryed
author_rank: Unknown
timestamp: July 05, 2023, 01:08:19 am
content: I made myself a usbgpib adapter (https://github.com/xyphro/UsbGpib) and use the python-usbtmc library to read remotely. I can write something quickly to graph in realtime if necessary.1000 readings/s is more than enough for my hobby needs.

author: rhb
author_rank: Super Contributor
timestamp: July 05, 2023, 03:08:16 pm
content: The AR488 will take care of logging. For hobby cal, join the USA cal club round 3. I logged both my 34401As for several days in round 2 against the excellent voltage references that @TiN designed and built.The most heavily used unit had been calibrated about a dozen times. The new looking unit had never been cal'd. Extensive checks with limited kit showed them in spec for everything I could test.Going price for a 34401A in NA is $325-$350. 3478A is $125. That's both ebay and the test equipment lists on groups.io. The 34401A may lack some convenience features, but the price-performance of the 34401A and 3478A can't be beat for reliability, accuracy and ease of repair or replacement.Have Fun!Reg

author: Veteran68
author_rank: Frequent Contributor
timestamp: July 06, 2023, 12:50:11 pm
content: I have an Agilent 34401A (newer generation of the HP with black+red probe connectors) purchased from a member here on eevBlog for $250 just a few years back. Excellent condition and per my hobbyist references is still well within spec and plenty accurate for me. If I had a local cal lab I'd like to get it calibrated, but calibration will cost more than I paid for meter, especially if I have to ship it somewhere. I consider it probably my greatest bargain find in this hobby. While I do plan to pick up a Siglent SDM3065 to have the newer features, I will keep this one. It's fast, has a nostalgia factor and there's just something sexy about a VFD! Plus you know what they say: two is one, and one is none.And do I *NEED* 6.5 digits for my hobby use? Not really, but I have a compulsion to get the best I can reasonably afford. I consider a good DMM to be the heart of any electronics bench and it's nice to know I have the extra precision should I ever need it. And I also have over a dozen handhelds ranging from higher end Fluke, Brymen, and Hioki to Uni-T, Aneng/Zotec, and Kaiweets (yes, I have a problem, I can't stop buying meters!). I've cut corners on a cheaper scope (not going to spend thousands for one when I seldom use it) and SigGen/AWG, but not my main DMM.