Upgrading my DMM game - Page 1
Forum section: electronics / beginners

author: Calaverasgrande
author_rank: Contributor
timestamp: May 16, 2021, 08:12:08 pm
content: I've gotten a lot deeper into my audio work during the lockdown.Built some vintage style inductor EQs with discrete op amps and transformer balanced inputs and outputs.Which then led me into upgrading my oscope, power supply and building test jigs for discrete op amps and completed 500 series modules.Now, like a hot rodded Honda Civic, the upgrades to my bench are shaking out the weaker links in the chain.My decades old DMM is no longer feature rich enough.Sure it still does V/A/R and continuity as well as diode test. But it lacks capacitance, RMS metering and any kind of hold function or autoranging.(Honestly autoranging isn't such a big deal though)RMS metering is of course useful for audio work. One can always do the math oneself, but what is the point of owning so much electronic gear if it doesn't do some of the math for us?Which brings me to the real question of the day. Is there such a thing as a DMM which is more appropriate for audio work? I'm imagining a bench meter which has a Decibel mode for certain types of measurements. Maybe a Cal mode would be required?I'm currently browsing HP and B&K bench meters on Ebay and having a tough time figuring out which would be an upgrade, and which would just be a larger meter that doesn't need batteries.

author: bdunham7
author_rank: Super Contributor
timestamp: May 16, 2021, 08:17:55 pm
content: If audio is your main thing, perhaps you should at least look at the Keithley 2015. They're expensive new, but show up on eBay for reasonable prices.

author: Calaverasgrande
author_rank: Contributor
timestamp: May 16, 2021, 09:13:23 pm
content: Wow the Keithley 2015 series really looks like it's taking no prisoners.I'm kinda shooting for something that causes less of a, how do you say, pecuniary impact?But those seem to do whatever one could require of a DMM.

author: jeffjmr
author_rank: Regular Contributor
timestamp: May 17, 2021, 02:23:38 am
content: +1 on the Keithley 2015. Despite the reported limitations of the THD feature, I find the THD figures mine reports to follow very closely with the specs of several different pieces of audio gear I have tried it on, and I have not yet sent it out for calibration.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 17, 2021, 03:29:09 am
content: If you're going for performance:Keithley DMM7510If you're going for gadget factor:Aneng AN888S.And for audio, it even has built-in bluetooth speakers!If you want a reliable and serious DMM for a reasonable price then have a close look at Brymen.For example the BM789. I does RMS upto 100kHz (according to spec) and it's an EUR150 class meter.

author: Martian Tech
author_rank: Regular Contributor
timestamp: May 17, 2021, 03:52:26 am
content: You didn't say what your budget is, but Fluke 8808a/Tektronix DMM4020 is a 5.5 digit bench meter that checks all your boxes except capacitance.

author: bdunham7
author_rank: Super Contributor
timestamp: May 17, 2021, 04:45:35 am
content: Quote from: Calaverasgrande on May 16, 2021, 09:13:23 pmI'd consider giving up the capacitance feature as a requirement and getting a handheld LCR meter instead--far more useful and a few hundred bucks tops for a halfway decent one. I use the capacitance feature on my DMMs because I'm lazy, but in reality, just measuring the capacitance alone with unknown test parameters isn't all that helpful. Eliminating this requirement will increase your options.As for a 'lesser pecuniary impact', I had a BK 2831E that was really a very good basic service bench meter. Dual display, 20,000 count, TRMS AC and AC+DC, continuity was quick enough, just a few seconds to boot, basic math functions including dB, frequency/period, 20-20kHz ACcurrentand 100kHz AC voltage, USB connection with free PC software. Pretty much what you need, equivalent to a top-of-the-line handheld in performance but more convenient for the bench and probably less expensive. $350 new and there's a used one on eBay right now for half that.

author: David Hess
author_rank: Super Contributor
timestamp: May 17, 2021, 04:16:24 pm
content: Quote from: bdunham7 on May 17, 2021, 04:45:35 amI second that. It is better to have capacitance on a separate instrument rather than limiting your choice of multimeter.QuoteMost multimeters do not come even close to covering the higher audio frequencies with any sort of accuracy so this is a useful selection criteria.

author: tooki
author_rank: Super Contributor
timestamp: May 17, 2021, 06:14:31 pm
content: Quote from: Calaverasgrande on May 16, 2021, 09:13:23 pmI have one and it’s my favorite meter overall.Buying one new is prohibitive, but with a little patience you can find a used one for ~$400.It doesn’t do capacitance, so you’d have to solve that separately. But that’s probably good advice anyway.

author: Calaverasgrande
author_rank: Contributor
timestamp: May 17, 2021, 06:17:55 pm
content: You are probably right about getting a separate device for measuring capacitance.I've lived for decades with no capacitance metering on my DMM.Really the idea is more to be able to get a rough approximation of the identity of the little discs I'm holding at the moment.Old guy eyes and all that.As far as budget, I'm trying to stick to $100-200 USD for a used bench meter.I can go higher for a good deal on a better tool that qualifies for the buy-once-cry-once exemption.I'm an advanced hobbyist not a pro, so I'm not willing to dump too much into this.Form factor is another difficult criterion.I prefer a bench meter, however I'm noticing some of the better used bench meters are about as big as a server meant for a 4 pole rack.At the other end we have these clock radio size bench meters (with bluetooth!) which will just not stack with other gear.I'm looking for a goldilocks meter I guess, like the size of one of these BK Precision or HP clamshell kind of boxes. Already have a BK function generator which gets the job done.

author: Calaverasgrande
author_rank: Contributor
timestamp: May 18, 2021, 09:58:45 pm
content: Oh heck, I didn't even notice those DMM spreadsheets.Especially this cool topic with a psuedo spreadsheet at the top.https://www.eevblog.com/forum/testgear/used-multimeter-buyer_s-guide/msg1143203/#msg1143203"UTSF!"Well I did, but not sure how I could have found this except by accident.Search terms are sometimes easier to formulate after you find the thing.Glad that I read about the VFD problems here on some of the DMMs I've been browsing. Almost jumped on a good deal on Ebay, then noticed how faint the VFD was. EEVblog saves the day again.

author: bdunham7
author_rank: Super Contributor
timestamp: May 18, 2021, 10:25:16 pm
content: Quote from: Calaverasgrande on May 18, 2021, 09:58:45 pmI don't see too many 'deals' on eBay anymore. Be careful out there!

author: Calaverasgrande
author_rank: Contributor
timestamp: June 06, 2021, 12:22:56 am
content: Went with a Keithley 175A off of the old bay.It's got most of the functions I need for now. And a GPIB port out back I should have some fun trying to utilize.Have to say, I cannot believe how many physically broken Keithley DMMs I had to wade through before I started finding ones that didn't look like they'd been run over by a truck.

author: David Hess
author_rank: Super Contributor
timestamp: June 06, 2021, 07:56:24 pm
content: Quote from: bdunham7 on May 18, 2021, 10:25:16 pmI haven't been in the market for years but recently did some searching and found a lot less "vintage" test equipment on Ebay.

author: wizard69
author_rank: Super Contributor
timestamp: June 07, 2021, 08:01:38 pm
content: Run over by a truck is right. It is either that or they have so many calibration stickers they are shocking and disgusting to look at. However I've found a great solution for stickies, that is flux remover, which works surprising well to remove the glue that covers many a meter.By the way I agree with others here when they suggest buying an LCR meter if you really need to measure capacitors. Your interest in inductors only strengthens the suggestion to get an LCR. As far as I'm concerned the capacitance feature on mulitmeters is in most cases useless. Basically an advertising gimmick to get people to buy that count features. In my old age the best feature a meter can have is big digits and an easy to read front panel. Many bench meters fail in this regard as you need to crane your neck to read key caps and legends.Quote from: Calaverasgrande on June 06, 2021, 12:22:56 am

author: bowzin
author_rank: Newbie
timestamp: July 01, 2021, 03:31:26 pm
content: Hallelujah, someone asked my exact question recently enough for me to piggyback!Calaverasgrande, did you land on something that worked for you? You had very similar criteria I was looking for, except I would take a handheld DMM also, but thought maybe a used bench model around $100-$200 might be a better "value".I am a hobbyist interested in 99% audio only use (beginner/intermediate stuff), but too new and green to know the ins and outs. I've heard many DMM's even over $200 aren't necessarily as accurate in the audio frequency range, but not sure where exactly that would arrive as a problem. Thanks!Quote from: Calaverasgrande on May 16, 2021, 08:12:08 pm

author: wizard69
author_rank: Super Contributor
timestamp: July 02, 2021, 09:55:40 pm
content: Quote from: bowzin on July 01, 2021, 03:31:26 pmAs for meter to use in audio work, your best bet is to compare data sheets. Your second problem is to determine what you will be doing with the meter and if a broad AC response is even important.As for "bench" meters, they are fantastic when working on a bench!! The minute you need to use it away from the bench, on battery power, they suck if not designed with a battery feature. Because of this issue I would strongly suggest a good quality handheld meter as your first meter. You should be able to do this around $200 and frankly going to the EEVBlog store is a good way to support the site. Now if site support isn't a big issue there are many meters to choose from and in that regard I'd go with local support as a big criteria. If you are in the USA there are several vendors you can go with when making a meter choice.It should be noted that there are additions you will likely want to invest in even after the meter purchase. A good set of test leads being one item. So you need to decide if these impact the initial budget or can be delayed into the future.Long term you will likely want or will benefit from having a bench DMM. You will also likely benefit from a bunch of other instruments (new, used, or homebrew). Finding the right mix is a challenge but I suspect a modern scope will be high on the list. At times a scope can be awkward but it can make up for the lack of a bench meter in some cases.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 03, 2021, 02:37:29 pm
content: https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/