What exactly are you looking to do? A Keithley 2015 THD isn't a "normal" bench multimeter and I'm not aware of any other 6.5 digit meters that can measure the distortion of a sine wave.
If all you want is an audio analyzer, there are lots of options on the market.
If all you want is an audio analyzer, there are lots of options on the market.
The data sheet for the 2015 THD says it'll measure down to -87 dBc. That's not exactly stellar. But if that's all you need, an HP 8903A or 8903B would work. See here for the difference between the A and the B versions: https://neurochrome.com/pages/hp8903
You may get lucky and find a tested 8903 on eBay for less than $1k.
The HP8903A I used to have measured down near -95 dBc (2 V, 1 kHz, 20 kHz BW). There's a more modern version of the instrument: Keysight U8903B. It'll set you back about $16k.
An external sound card and some software on your computer will do the trick as well, though, the software often lacks an actual display of the THD.
There are many other options as well.
Tom
You may get lucky and find a tested 8903 on eBay for less than $1k.
The HP8903A I used to have measured down near -95 dBc (2 V, 1 kHz, 20 kHz BW). There's a more modern version of the instrument: Keysight U8903B. It'll set you back about $16k.
An external sound card and some software on your computer will do the trick as well, though, the software often lacks an actual display of the THD.
There are many other options as well.
Tom
Good morning everyone ! Precisely I was looking for an analyzer capable of measuring the harmonic distortion of the output signal of the amplifiers and on a video that I happened to see on facebook I saw that he used this type of instrument!However, if there are more reliable solutions and perhaps with a lower cost as possible, I am very happy to accept advice🙂
Don't you want to use a decent soundcard plus software? Or is there a reason to use hardware distortion meter?
+1 for a good soundcard. Something like the MOTU M2, which has pretty darn good specs.
Alternatively, look at the QuantAsylum QA403 for an easy to use dedicated audio analyser for $549.
I have a Keithley 2015, a QA401 and a good soundcard. I've used the 2015's distortion analysis feature exactly once (as Tom said, its specs are pretty poor). The QA401 does the vast majority of the work, as it's really easy to use and has excellent specs for the price.
Edit: I see the QA403 is out of stock for a few months - you might want to sign up for their newsletter to get notified when it's back. This dang chip shortage is such a pain in the backside!
Alternatively, look at the QuantAsylum QA403 for an easy to use dedicated audio analyser for $549.
I have a Keithley 2015, a QA401 and a good soundcard. I've used the 2015's distortion analysis feature exactly once (as Tom said, its specs are pretty poor). The QA401 does the vast majority of the work, as it's really easy to use and has excellent specs for the price.
Edit: I see the QA403 is out of stock for a few months - you might want to sign up for their newsletter to get notified when it's back. This dang chip shortage is such a pain in the backside!
I also have a 2015. its an excellent meter and a decent audio analyzer by the standards of 15 years ago. Mine measures reliably down to .001%, but that's its floor. Its source is not that good. It is programmable and you can use it to do a pretty comprehensive set of tests of an audio project. I made it this far: https://github.com/1audio/Keithley-Windows-10 but its not really finished.
The 2015 is still my primary bench meter. I have adapted to its foibles. . . They sold a lot to cell phone assembly lines for production test. Those still pop up used. for $350 its a great deal. Much more and no!! A QA403 is a much better investment for audio. Get a scope and an OK meter and you will not be held back by your equipment, just you skills and determination.
The 2015 is still my primary bench meter. I have adapted to its foibles. . . They sold a lot to cell phone assembly lines for production test. Those still pop up used. for $350 its a great deal. Much more and no!! A QA403 is a much better investment for audio. Get a scope and an OK meter and you will not be held back by your equipment, just you skills and determination.
FWIW, the 2015 is a Keithley 2000 6 1/2 digit DMM with the addition of a second board that has a fixed point digital signal processor, a delta-sigma ADC to do the audio measurements, and a direct digital synthesizer to generate the sine wave output. I know because I designed the circuitry on that board. It was intended to perform 100% production tests of the audio on early cell phones (pre smart phones), and, indeed its noise floor and distortion limitations are not good enough for the highest end solid state audio. Probably just fine for class A tube amps and speaker testing.
I saw comments about the QA403 and went to their website to check it out; quite impressive, wish this retired old guy could find an excuse to buy one.
I saw comments about the QA403 and went to their website to check it out; quite impressive, wish this retired old guy could find an excuse to buy one.
