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Is it possible to measure phono cartridges like you do DACs?

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#1
Just curious if there's an objective way to scientifically measure performance of phono cartridges that would offer predictable and reliable guidelines for the record-listening crowd? I understand that there are factors in play other than the capacitance, inductance, etc; like stylus shape, cantilever type, enclosure, etc. Taking these multiples in consideration, is it possible at all to offer objective data that would translate into the sound qualities?
 

sergeauckland

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#3
In my early life, I did a fair few measurements on phono cartridges and turntables, and the main problem was always the quality of the test records.

Frequency response test records have a guaranteed performance lifetime of only 5 plays above 5kHz, after which the HF level isn't guaranteed any more due to wear. That's why frequency response LPs like the Decca have the same sweeps on both sides, to double the potential lifetime. Whether Decca were especially pessimistic I don't know, but other test LPs I had (professional ones, not the ones sold for enthusiasts to do their own tests like the Shure Audio Obstacle Course) were similarly restricted.

Tests for mistracking have a one-time use, as once an LP gets mistracked, the grooves are permanently damaged. That's why when I do mistracking tests, I stop the instant I hear/see mistracking, and move to a different part of the LP for each test, so that I don't mistake groove damage for mistracking.

Distortion, wow and flutter and rumble measurements all depend on how good the cutting and subsequent pressing are. Distortion depends on that introduced by the cutting lathe, and I've never seen any figures for how good that is. Wow and Flutter depends on the LP being perfectly concentric, as even a mm or so of eccentricity in the centre hole can result in more W&F than a good turntable produces. Rumble depends on cutting lathe rumble, and judging by the rumble on one or two of my 'silent groove' LPs, that's often much more than the turntable produces. The best (i.e. most consistent) way of measuring rumble is using a bridge device, but then the numbers that produces may not be comparable with the way the manufacturer specified their turntable.

As LP playback is not a mainstream quality medium....yes I know it can produce very satisfactory subjective results.......there's not much around in the way of new test LPs, old ones are of unknown quality so any measurements are suspect.

It should be possible, and I think it has been done, to use a vibrating platform to exercise the cartridge to get a frequency response and distortion measurement, and it could possibly also be used for mistracking, but I don't know of a commercial product like that. Of course this would test the phono cartridge only, and not the arm and turntable.

S.
 

Ron Texas

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#4
Phono cartridges don't measure anything like electronics. They have significant frequency response deviations and far more distortion. Vinyl is a whole different world.
 

restorer-john

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#6
Tests for mistracking have a one-time use, as once an LP gets mistracked, the grooves are permanently damaged. That's why when I do mistracking tests, I stop the instant I hear/see mistracking
What's funny about that is I always believed the same, that was until we compared three identical test records, two of which had been never used and the other one I grew up listening to as a child. There were no changes to the 'clean-ness' of the high level tracking and stepped drum beat tests (up to +16dB) I was surprised as I figured the well used one would be 'worn out'. The 10Khz tracks were all essentially the same.

Yes, I can recite the tests, the accent of the announcer and the order of tracks on that particular test record my Dad used through the 70s seemingly hundreds of times while testing his various turntable and cartridges. I think I was audibly brain-washed as a young boy... ;)

That was a W&G test record. Very thick, shiny vinyl with a milled edge.

The W&F tracks are remarkably good in terms of accuracy and eccentricity and I used them for W&F testing of TTs I restore. My Kenwood W&F meter can read from 0.002% and up, with separate Wow, Flutter, unweighted and weighted W&F with selectable JIS/CCIR/DIN standards. (3150Hz or 3K) The HFN test record has some serious frequency errors on it and W&F track is essentially useless as a result.

I have a few others including an Ortofon one, which has some excellent alignment and tracking tests on it.
 

sergeauckland

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#7
I did wonder whether the '5 plays' guarantee I referred to was unnecessarily pessimistic, but that was what these test LPs quoted. I also wonder whether the lack of damage was in part due to the high trackability cartridges of the 1970s causing much less wear, and tracking the +16 or +18dB bands at around 1gm, without causing any damage. Now we use cartridges that track at 2-3gm, albeit we now often use cartridges with a line-contact profile that has a wider contact 'footprint' so should cause less damage.

Maybe Decca were thinking of their own cartridges...........

The honest answer is that I don't know. I have test LPs from the 1970s that are still usable, but can't vouch for their accuracy. I certainly agree that the HFN test LP produced by Len Gregory is useless for making measurements. I had some correspondance with HFN over this, and LGs response was along the lines that the tests are for listening to, not measuring....make of that what you will!

The Test LP I find accurate, insofar as it hasn't given me reason to doubt it, is the Ultimate Analogue Test LP, although this one doesn't have high level trackability bands.

By the way, being able to recite the words, I used to be able to recite the Ampex and BASF Alignment tapes as I used those several times a day in my first job. Those also had a limited life, as I recall, and my employer at the time threw them away once they had their number of plays, so they wouldn't get used. I took a set home, and they served me well for many years as being 'good enough' for home use.

S.
 

SIY

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#11
You can do very relevant and replicable measurements on phono preamps. Unfortunately, very few people do them properly or hit all the important measurements.
 
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#12
It is possible to test cartridges. There are review sites that already do that, but it's not common practice. Accuracy of test records is an issue, which is why you probably want to stock up on something like the old CBS test records if you are doing this.

The main things you would want to measure are the frequency response, the trackability, stereo separation, output, etc. Sometimes these things deviate considerably from the manufacturer's specs from example to example.

The Miller Audio Research tests are interesting to look at. They've tested phono preamps as well.
 

amirm

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#15
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#16
There is as much high end balderdash written about phono preamps as there is about high end anything else. Pinpoint images, black velvet backgrounds, my wife could hear the difference in the kitchen at the other end of the house while washing dishes, etc. $60,000 for a phono stage with a 54db SNR Silly phono. So much of high end "engineering" seems to be how do we do this simple amplification task with the maximum number of components in the largest amount of space. I have a bottom of the line phono preamp from Simaudio that retailed for $650 and I got it on a clearance sale for $350. Looking inside, even that seems a bit high. However, it has a factory specified SNR 104db ref full scale or about 93db ref consumer audio nominal level at the MM input and 73db MC. It also has better THD spec's than the $60K unit, both of which are low enough to be inaudible. As usual, we are expected to believe that the super expensive unit possesses magical audio qualities that can't be measured by any known test method but can be easily heard by a tone deaf 70 year old from across the street. Other than power amplifiers, beware of any audio component that comes in a giant box or many boxes. Most of that space is filled with the electronic equivalent of bull output.
 
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sergeauckland

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#17
There is as much high end balderdash written about phono preamps as there is about high end anything else. Pinpoint images, black velvet backgrounds, my wife could hear the difference in the kitchen at the other end of the house while washing dishes, etc. $60,000 for a phono stage with a 54db SNR Silly phono. So much of high end "engineering" seems to be how do we do this simple amplification task with the maximum number of components in the largest amount of space. I have a bottom of the line phone preamp from Simaudio that retailed for $650 and I got it on a clearance sale for $350. Looking inside, even that seems a bit high. However, it has a factory specified SNR 104db ref full scale or about 93db ref consumer audio nominal level at the MM input and 73db MC. It also has better THD spec's than the $60K unit, both of which are low enough to be inaudible. As usual, we are expected to believe that the super expensive unit possesses magical audio qualities that can't be measured by any known test method but can be easily heard by a tone deaf 70 year old from across the street. Other than power amplifiers, beware of any audio component that comes in a giant box or many boxes. Most of that space is filled with the electronic equivalent of bull output.
I agree with the above. I can't see what's difficult about an RIAA equalised amplifier, which wasn't already solved back in 1975, if not earlier. There's no significant difference between an RIAA equalised amplifier with a mV sensitivity and a tape head replay amplifier, nor much difference except for the rather extreme EQ, with a low noise microphone amplifier. It's all known stuff. A simple opamp and feedback can do everything that's needed to be quite good enough considering the limitations of vinyl replay.

From the measurements I've seen, it looks like performance has gone backwards from the 1970s, as RIAA accuracy and overload margin have been sacrificed on the altar of subjectivity and 'sounding good'! I can't see any technical benefit of these hyped phono stages compared with something like the Cambridge Audio or Project phono stage which are as good as they need to be.

S.
 
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