Phono Cartridge Response Measurement Script

[dlaloum]

One measurement of the OM40 back then.

View attachment 296833

The OM40 is/was a superb cartridge...
But this chart obfuscates due to it's scale - that single pixel rise above 15kHz is of import...

 

[JP]

I’ve several copies that measure within 1dB. Not sure what’s mythical about that.

 

[dlaloum]

I’ve several copies that measure within 1dB. Not sure what’s mythical about that.

Sure - but that wasn't the spec. - and individual example variations, as well as loading variation, could easily push it to and outside of the spec

 

[JP]

Improper loading can push anything outside of spec. I’ve just never seen them measure that poorly.

 

[USER]

I compared 6 VN5MR styli here, and the results show two consistent trends: https://audiosciencereview.com/forum/index.php?threads/mm-vs-mi-vs-mc.18636/post-1383126

The loading is much too high because it was adjusted to the CBS record, and I have plenty of evidence that the hump roughly between 8.5 and 17kHz is that particular record (#2), so if you can see past that and draw a straight line you can see the two trends, half with tails pointing up and half with tails pointing down. The one that I used as my first example in the library thread is one of the ones that points up, which measures within 1dB as JP notes. I have several of those. The ones pointing down are very consistent with each other and I don't see any evidence of any major variation other than the two trends, which is commendable.

I'm going to do another big VN5MR stylus comparison at some point now that I have things dialed down but if the difference isn't due to something like suspension trouble, stylus-cartridge fit (including not being pushed in all the way), or just me fucking up, then I would bet that the results for the ones pointing down are closer to a measurement previously reported on this thread by a member and in this review. Would that relate to a -2.5dB spec if there was any sort of production change? I find those numbers, from good companies, to usually be conservative anyways.

 

[dlaloum]

I compared 6 VN5MR styli here, and the results show two consistent trends: https://audiosciencereview.com/forum/index.php?threads/mm-vs-mi-vs-mc.18636/post-1383126

The loading is much too high because it was adjusted to the CBS record, and I have plenty of evidence that the hump roughly between 8.5 and 17kHz is that particular record (#2), so if you can see past that and draw a straight line you can see the two trends, half with tails pointing up and half with tails pointing down. The one that I used as my first example in the library thread is one of the ones that points up, which measures within 1dB as JP notes. I have several of those. The ones pointing down are very consistent with each other and I don't see any evidence of any major variation other than the two trends, which is commendable.

I'm going to do another big VN5MR stylus comparison at some point now that I have things dialed down but if the difference isn't due to something like suspension trouble, stylus-cartridge fit (including not being pushed in all the way), or just me fucking up, then I would bet that the results for the ones pointing down are closer to a measurement previously reported on this thread by a member and in this review. Would that relate to a -2.5dB spec if there was any sort of production change? I find those numbers, from good companies, to usually be conservative anyways.

View attachment 296867

To be certain, you have to calculate the impact of the loading circuit, and deduct it from the F/R to determine the "pure" cantilever response (with minor contributions from things like eddy currents and other extraneous minor impacts!)

However, a rise at the top end generally would imply a higher effective mass - as the cantilever resonance is lower in frequency, pushing the high end response up...

 

[USER]

To be certain, you have to calculate the impact of the loading circuit, and deduct it from the F/R to determine the "pure" cantilever response (with minor contributions from things like eddy currents and other extraneous minor impacts!)

However, a rise at the top end generally would imply a higher effective mass - as the cantilever resonance is lower in frequency, pushing the high end response up...

Yeah, but no one here is doing that.

As far as your second point, that's why I'm interested to see if I can find any evidence pointing to a possible production change. Clearly delineated patterns could help. But again, I could have screwed up those measurements.

 

[dlaloum]

I have a spreadsheet that models the electrical performance and deducts it then plots the result...

Developed it with the help of LuckyDog on VinylEngine about 12 years ago... (LD disappeared a while back...)

I can share it... it's a bit rough - you need to import CSV's into the right place, and at the right resolution otherwise you have to reformat all the plots - but still it provides some interesting analysis

 

[USER]

I have a spreadsheet that models the electrical performance and deducts it then plots the result...

Developed it with the help of LuckyDog on VinylEngine about 12 years ago... (LD disappeared a while back...)

I can share it... it's a bit rough - you need to import CSV's into the right place, and at the right resolution otherwise you have to reformat all the plots - but still it provides some interesting analysis

I'll ask you about it in a week or so. I've been swamped trying to make sure the library thread wasn't a disaster at the start. Lots of stress making sure I got the first few measurements right. And a short-lived little emergency with the phono pre as well, lol.

 

[dlaloum]

I'll ask you about it in a week or so. I've been swamped trying to make sure the library thread wasn't a disaster at the start. Lots of stress making sure I got the first few measurements right. And a short-lived little emergency with the phono pre as well, lol.

It's fiddly and a bit of a pain to use... thrown together more than 10 years ago - but it does expose the "raw" performance

 

[Thomas_A]

I let you Measure them then before I buy!!

I saw your additions in the library thread. I made some search tests to find the actual measurement posts and eg ”Shure” gives many hits. If you add the cartridge name as headline/the first line in bold, it will be easier to track down the actual measurement posts since it will be the first word in the search result for each post. I think it is a good idea to have it so. The thread will be long and searching for the actual measurements posts will be tricky if there is no first cartridge headline

 

[Thomas_A]

I have a spreadsheet that models the electrical performance and deducts it then plots the result...

Developed it with the help of LuckyDog on VinylEngine about 12 years ago... (LD disappeared a while back...)

I can share it... it's a bit rough - you need to import CSV's into the right place, and at the right resolution otherwise you have to reformat all the plots - but still it provides some interesting analysis

Have you seen LD lately? Last I saw him was on DIY audio. Would be nice to have him here, if he still is around.

 

[dlaloum]

Have you seen LD lately? Last I saw him was on DIY audio. Would be nice to have him here, if he still is around.

Yes - he would be a valuable contributor here... but I have not seen him online in years (perhaps frequenting other forums...)

 

[USER]

I saw your additions in the library thread. I made some search tests to find the actual measurement posts and eg ”Shure” gives many hits. If you add the cartridge name as headline/the first line in bold, it will be easier to track down the actual measurement posts since it will be the first word in the search result for each post. I think it is a good idea to have it so. The thread will be long and searching for the actual measurements posts will be tricky if there is no first cartridge headline

Now we are rolling. And, yes, now that we have an idea of what the thread will look like, I completely agree.

@Balle Clorin if you could move things around to the following structure we would greatly appreciate it. The graphs sort of get lost when placed at the bottom of the post.

Name of Cartridge in Bold
Graphs
Notes


I'll add your contributions to the index. I am hoping to find a neat and orderly way to link to the individual measurements from within there.

 

[dougi]

I received a copy of the CA-TRS-1007 test record today. Last retail copy in Oz I think. I hope to run through my carts this weekend and post on the cart thread. I've run them all through the Elipson white noise track so there should not be any surprises, but I am interested in how my 15YO Dynavector DV20XL fairs w.r.t. channel separation and distortion, after lengthy hours and a restraightened cantilever after bending it on the side of the platter. I will also try and work out a correction for the Elipson test record sweep track by comparison with the CA-TRS-1007 (not that I can seem to buy the Elipson in-country anymore either).

 

[Balle Clorin]

My CA-TRS-1007 is not the best on channel separation so do not become disappointed. My Ortofon and Bruel & Kjær QR2009/2010 show better than 30db separation on sweep, while CA TRS-1007 show -25 /-32and opposite side deviation compared to most other test records. For Frequency response CA is one of the best , better than Elipson and close to QR2009 which is my best, I think…

Frequency Response Test Records

Frequency Response Test Records I was wondering how my few test records measure compared to each other and which one is the best for measuring crosstalk. Used Pickup: Ortofon Vinyl Master Silver (47K//240pF, 17,5mN) Used Turntable: Mitsubishi LT-20 First I adjusted the pickup exaktly...

audiosciencereview.com

 

[morillon]

these tracks of "fr" have just not been made mainly to observe the croostalk via scanning...
very little seems possibly exploitable on this point.
the fact that the script easily allows it does not make it always relevant
;-)

 

[Balle Clorin]

Well all official plots from producers use the JVC TRS-1007 sweep to document both Frequenct AND crosstalk . Too bad there are too few copies of this record ..

 

[morillon]

""jvc for every body!!""

(in many other cases of "source" it is useless to integrate this measure... and we can often observe it here)

;-)

 

[JP]

It was a selfish inclusion.