Keithley 2015

[BillyO]

Happy New Year!!

Working and accurate Keithley 2015 for $300.

Good deal?

Is it a reliable unit?

Is the THD function up snuff for decent audio work?  Not audiopholl level.  Nothing reasonable satisfies them.  Just for working on vintage Hi-Fi gear (Pioneer, Sony, Marantz, etc..)

[KungFuJosh]

The P models are supposed to be better for audio. 2015-P and 2016-P. I'm tempted by both, but have no experience with either.

I see the 2015THD model frequently around that price.

[BillyO]

It is a THD model.

So, not a bad price?

I can always use in in conjunction with my scope to get THD and specific harmonic information.

[KungFuJosh]

The price is good if it's a local enough deal. Local cash sale? Buy it. feeBay from overseas with sketchy return policy / unreliable condition description / unreliable feedback? I'd pass.

[BillyO]

It's local (No shipping! Yay!) and I can get my money back if returned within 14 days as well as check it out before I bring it home.

My usual source.

[Smokey]

It's local (No shipping! Yay!) and I can get my money back if returned within 14 days as well as check it out before I bring it home.
My usual source.

I don't have a 2015, but I would imagine it would suck using the THD features through the front panel.  If those are the features you are looking for, I would just get ready to automate it now.

Also, as a heads up, those Keithley 2000's that it's based on have common capacitor issues that cause real damage to the PCB if they leak.  Look that up and maybe just plan on replacing those capacitors.

[J-R]

I recall a previous discussion about the 2015 THD where it was revealed they were made for basic cell phone testing back in the day.  So the audio performance of the unit isn't particularly great because the requirements were low.  I'd probably suggest further research on the specifics, although if you can return it within 14 days you could just try it for yourself.

Otherwise, yes, the potential capacitor issues, but also the back of the buttons and PCB might need to be cleaned to restore proper operation and then there is the VFD display burn-in depending on what it has been doing all its life.

[KungFuJosh]

Yes, to all that, but still pretty darn good for $300 local, and a return window. If the screen needs replacing, even better: https://www.eevblog.com/forum/testgear/keithley-2000-2015-2016-2001-vfd-to-led-display-conversion/

[BillyO]

Are these as bad for capacitors as the HP 34401?

I'm recapping one of those right now.  The aluminums were on the way out but 3 of the tantalums have literally blown up and are missing their (-) pad.  Obliterated along with two Zeners.  I think I've devised a way to replace those pads and bridge (bodge) to the broken traces that will look and function reasonably.  The real pain was removing the VFD to prophylactically replace the two tantalums under that, but the operation went well.

Fun stuff!

[Kleinstein]

The Al electrolytics in many Keithley meters were really bad, with a tendency to leak and cause damage (especially with the K2001,2002) to the PCB if not dealed with in time. On the upside shorted tantalum is less of an issue.

[Tony_G]

I like my 2015THD - One thing that was a problem was the FET leakage for the 10GOhm range, but other than that, nice piece of kit.

TonyG

[G0HZU]

I bought my 2015THD something like 12 years ago and it is still working fine. I check the internal electrolytic caps every couple of years and they always seem to be fine.

I do think it works best when automated via GPIB and I've used mine for lots of automated testing. The THD performance is fairly good, with harmonic distortion down at about -80 dBc but the THD+N isn't so good. I can't remember for sure  but the last time I measured THD+N it was in the order of 65dB which is reasonable but far from impressive.

The SINAD feature works well and is very accurate for SINAD values associated with comms receiver testing. Again, this is best done remotely via GPIB and a laptop etc.

The 2015THD also has an internal audio generator and this is quite accurate in terms of amplitude so could be used for checking a basic H/H DVM on the AC range or for checking a scope etc. The harmonic distortion on the generator is not so good but is fine for comms stuff and probably for basic HiFi stuff. I wrote a sine and sweep generator utility for my 2015THD that is controlled via GPIB and this worked really well producing fast and smooth sweeping.

The THD performance is quite fast via GPIB and I wrote a utility for this back in 2013 here:



You can see I measured a decent square wave with it and used the marker feature to measure the harmonic levels and they agreed closely with theory. At the very end of the video I briefly measured a sine wave and you can see the typical harmonic distortion levels are around -80 dBc. Some distortion is from the source and some is from the 2015. Although this all looks neat, I think it's better to do this stuff with a decent internal or external sound card. I haven't used the 2015 with this THD program very much at all because a sound card is much better.

[tooki]

The P models are supposed to be better for audio. 2015-P and 2016-P. I'm tempted by both, but have no experience with either.

I see the 2015THD model frequently around that price.

FYI, just to be clear, there’s no such thing as a “2015THD”. (Implying the existence of a non-THD version of the 2015.)

The model numbers in the series are 2015, 2015-P, 2016, and 2016-P. All of them can measure THD.

The 2015 and 2016 are the “THD multimeters”.
The 2015-P and 2016-P are the “audio analyzing multimeters”. (The P versions add spectrum analysis. The P is for “peak”, as in “peak spectral components”, per the datasheet.)

The 2015(-P) has 4V output, the 2016(-P) has 8V output. Other than that, identical.


The reason people mistakenly think there is a “2015THD” is simply because the front panel says “2015 THD Multimeter”. But that isn’t intended to mean [2015 THD]+[Multimeter], it’s actually [2015]+[THD Multimeter].

[BillyO]

 

[tooki]

Happy New Year!!

Working and accurate Keithley 2015 for $300.

Good deal?

Is it a reliable unit?

Is the THD function up snuff for decent audio work?  Not audiopholl level.  Nothing reasonable satisfies them.  Just for working on vintage Hi-Fi gear (Pioneer, Sony, Marantz, etc..)

That’s a great deal. I have a 2015 and love it.

Essentially, the 2015 is a 2000 with an added board, but often sold for cheaper on the used market because they’re less known.

I don’t actually use the THD analysis feature, but my understanding is that it’s not really that precise for audio work. While it can be used standalone to an extent, the THD analysis is really intended to be used by remote control for automated testing.

Even if this doesn’t solve your THD measurement needs, $300 is a fabulous price for an outstanding everyday bench meter, and I’d pounce on it.

[tooki]

Care to elaborate?

[gamalot]

My first 6.5 digit multimeter was the Keithley 2015, but I've actually never used its THD measurement feature.

It’s basically a Keithley 2000 with a THD module added, and they gave up the multi channel card slot to make room for it.

[BillyO]

Care to elaborate?

Sure.  I just think everyone knew that already.

As to the distortion measuring ability, it can measure from 0.002% up to 100%.  For all but the most diehard audiophools, that should be good enough.  Personally I can't hear less than about 0.5%, but then again, I'm nearly deaf. 

Just to add to this.  My first career in electronics was working as a maintenance technician in a recording studio.  We aimed for less than 3%.  No kidding.  I also had a parttime weekend job selling stereo equipment.  I used to have a hard time controlling myself from bursting out laughing when customers complained that such and such a receiver was appalling because it was only rated at 0.05%, or things to that effect.   

[G0HZU]

The reason people mistakenly think there is a “2015THD” is simply because the front panel says “2015 THD Multimeter”. But that isn’t intended to mean [2015 THD]+[Multimeter], it’s actually [2015]+[THD Multimeter].

FWIW if I look at the front panel fonts of my meter, it clearly says 2015 THD MULTIMETER
The 2015 and THD share the same bold fonts but MULTIMETER is not in bold. If you can't immediately see this then compare the T characters

That's why I always refer to my multimeter as a 2015 THD. It's how it is described on the front panel and that's why I think a lot of people also refer to it as a 2015 THD even if this is wrong. I don't really care that the official model number is reduced to 2015 at the factory or in the manual or via GPIB. I'll always refer to it in the way it is labelled on the front panel as a 2015 THD

[G0HZU]

It's probably worth mentioning that my Keithley 2015 THD weighs just under 5 kg and the power consumption is typically about 15 W (and 28 VA) in the default DC volt mode. So it is very heavy for a bench multimeter and the power consumption is quite high too. It runs warmer than the other meters because of the 15W power consumption so I always place it alone on the bench away from anything else. Probably not ideal to place another meter on top of it...

I also have a Keithley 2000 model and it is quite a bit lighter at 2.7 kg and the consumption is about 8 W (and 10 VA) in the default DC volt mode.

I also have an Agilent 34401A and it weighs 3.3 kg and the consumption is about 8 W (and 17 VA) in the default DC volt mode.

All three meters produce some hum from the mains transformer. The 34401A is the loudest, followed by the 2015 THD and the quietest is the 2000. The hum from the 2015 THD is barely noticeable unless I really listen for it up close so it's not an issue at all. 

[tooki]

Care to elaborate?

Sure.  I just think everyone knew that already.

I’m not so sure they do!

[BillyO]

Well, let's help them out:  https://download.tek.com/datasheet/1KW-61135-1_2015_Datasheet_071019.pdf

[tooki]

The reason people mistakenly think there is a “2015THD” is simply because the front panel says “2015 THD Multimeter”. But that isn’t intended to mean [2015 THD]+[Multimeter], it’s actually [2015]+[THD Multimeter].

FWIW if I look at the front panel fonts of my meter, it clearly says 2015 THD MULTIMETER
The 2015 and THD share the same bold fonts but MULTIMETER is not in bold. If you can't immediately see this then compare the T characters

That's why I always refer to my multimeter as a 2015 THD. It's how it is described on the front panel and that's why I think a lot of people also refer to it as a 2015 THD even if this is wrong. I don't really care that the official model number is reduced to 2015 at the factory or in the manual or via GPIB. I'll always refer to it in the way it is labelled on the front panel as a 2015 THD

What’s weird is that they seem to have changed this at some point. See the attached photos: some units show “2015 THD Multimeter”, others show “2015 THD Multimeter”. (The datasheets and manuals, however, have never considered “THD” to be part of the model number.) I’m pretty sure mine has the THD in bold, since it’s an older unit.

On the other hand, every picture of a 2015-P/2016-P formats it like “2015-P Audio Analyzing DMM”.

[MadTux]

It's probably worth mentioning that my Keithley 2015 THD weighs just under 5 kg and the power consumption is typically about 15 W (and 28 VA) in the default DC volt mode. So it is very heavy for a bench multimeter and the power consumption is quite high too. It runs warmer than the other meters because of the 15W power consumption so I always place it alone on the bench away from anything else. Probably not ideal to place another meter on top of it...

I also have a Keithley 2000 model and it is quite a bit lighter at 2.7 kg and the consumption is about 8 W (and 10 VA) in the default DC volt mode.

Simple solution, just open the case and unplug the THD board on the bottom ;-)
Then it's basically a K2000, don't think it even gives any errors, just THD function isn't working any more.

Generally K2015s on ebay seem a lot newer and in overall better/nicer condition than the average yellowish ebay K2000 from the 1990s.
Lots of K2015 are from China nowadays, no idea why.

[BillyO]

Maybe for the same reason there are lots of 7510s.  I'm guessing government funds for technology upgrades.