In my experience of owning 6, 6 1/2 digit bench meters, none less than 20 years since adjustment, they were all in spec. Typically in spec or broken. My first suggestion for a meter for audio is a Fluke 8060A. They are all old BUT every one i have seen is in cal. They have tighter specs than most of Flukes' current premium handhelds. And features useful for audio like dB. $100- $200 on eBay. Calibration seems to be around $130 to $150. Lots of discussion on the 8060A at EEVblog forum. The designer occasionally pops up there.
Fluke 8060A (above) is good to 100 KHz +/- 3%. Keithley 2015 good to 300 Khz. +/- 0.5% Fluke 8506A is TRMS to over 1 MHz but its an outlier special instrument. audio band +/- 0.02%, 1 MHz +/-3.5 % If extended AC TRMS is important there is a handful of good options- HP 3400 10 MHz, HP 3403A 100MHz, Fluke 8922 11 MHz.
Be careful Voltnuttery lies down this path.
Fluke 8060A (above) is good to 100 KHz +/- 3%. Keithley 2015 good to 300 Khz. +/- 0.5% Fluke 8506A is TRMS to over 1 MHz but its an outlier special instrument. audio band +/- 0.02%, 1 MHz +/-3.5 % If extended AC TRMS is important there is a handful of good options- HP 3400 10 MHz, HP 3403A 100MHz, Fluke 8922 11 MHz.
Be careful Voltnuttery lies down this path.
THE CALIBRATABILITY OF VARIOUS PRODUCTS
What is the situation regarding the amount of 'calibratable functions' a DMM can have?
[ I noticed some time ago that some electronic devices changed to higher tolerance manufacturing at the reduction of calibratability ]
What is the situation regarding the amount of 'calibratable functions' a DMM can have?
[ I noticed some time ago that some electronic devices changed to higher tolerance manufacturing at the reduction of calibratability ]
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We moved to "closed case" calibration. The reason for that is that moving shields affects HF response greatly, and temperature variations also affect everything. I made case covers with drilled holes to adjust most meters in the cal lab, especially Fluke 87 and related as we saw a lot of them. You could optimize the calibration only to find it was way out whenm you put it back together. Using a drilled case to adjust it helped a lot, but putting the original case on did change things. Huge improve though. The amount of adjustment points are usually greater than the old trim pot/capacitor types.
When I left the lab, I sent those cases to the Rochester lab to someone who appreciated them.
Some meters use electronic calibration (closed case), but the way they are made means the calibration will not hold. It is simply pointless to trust a cheap meter. Right now I would only buy Fluke, Keysight (Agilent / HP) or Keithley hand held meters. Probably the same for bench meters too.
Today's Keysight bench meters keep the voltage reference in an oven, constantly powered. Demian would understand the significance of that.
When I left the lab, I sent those cases to the Rochester lab to someone who appreciated them.
Some meters use electronic calibration (closed case), but the way they are made means the calibration will not hold. It is simply pointless to trust a cheap meter. Right now I would only buy Fluke, Keysight (Agilent / HP) or Keithley hand held meters. Probably the same for bench meters too.
Today's Keysight bench meters keep the voltage reference in an oven, constantly powered. Demian would understand the significance of that.