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In Reply to: RE: cm/s for output voltage posted by jason.hockman@gmail.com on May 10, 2010 at 13:11:51
The 5cm/sec is a standard promoted by Shure and the 3.54cm/sec is a JVC standard measurement. Many years ago velocity standards were all over the place and some standardization was needed.
Shure or JVC test records were the standards used in the heyday of vinyl. I suppose that has as much as anything to do with the adoption of the two velocities for cartridge ouput specs.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
Follow Ups:
A test record signal of 5-cm/s velocity in the lateral (mono) direction has 3.54-cm/s velocity in the 45-degree (stereo) direction.
Best regards,
John Elison
When cartridges are reviewed somtimes the reviewer will state the cartridge's output relative to the JVC 1007 test record (3.54 cm/sec) and the CBS STR-100 test rcord (5 cm/sec).
If these are different views of the same velocity then why does the cartridge in question have different output voltages for each test spec (the output will always be lower for the JVC)?
Inquiring minds want to know,
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
It depends on several factors such as accuracy of the test records, peak versus RMS velocity, mono versus stereo direction of the measured velocities, etc. All I can tell you with absolute certainty is that a lateral velocity of 5-cm/s will produce a 45-degree stereo velocity of 3.54-cm/s. That is a fact.
Best regards,
John Elison
But there has to be a difference between those two test records based on the fact that they generate two different outputs from the same cartridge under test.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
It's obvious there must be a difference between the two test records; I just can't explain what is causing the difference because I don't own the JVC test record. Here is the statement on the back cover of the STR-100 Test Record.
Some people believe that the zero-dB reference for vinyl is 5-cm/s peak lateral velocity. If the JVC test record is cut to 5-cm/s peak lateral velocity, then it would have a 3-dB lower signal level. Or, if the JVC test record is cut to 3.54-cm/s RMS lateral velocity, that would also produce a 3-dB lower signal level. However, without knowing the specifics for the JVC test record, it is impossibly to determine the cause of the difference.
Best regards,
John Elison
Edits: 05/11/10
It was on Yosh's site again but it was in Japanese. I used Google to translate it, saved it as a PDF and placed it at the link below.
We don't shush around here!
Life is analog...digital is just samples thereof
There might be accuracy problems in one or both of the test records. The JVC test record does not specify RMS for the velocity. Normally, if nothing is specified, RMS is assumed -- at least that is true for voltages. One method to determine the actual signal level of the grooves would be to measure their amplitude microscopically. Unfortunately, I don't have a measurement microscope and I don't own the JVC test record.
Bands 5 and 6 on the JVC test record correspond to Bands 6A and 7A on the STR-100 test record. They should be the same level if they are both 3.54-cm/s RMS 45-degree velocity. Do you know the level difference from a specific cartridge that lists its output from both records? If so, we could easily determine the decibel difference. If it turns out to be exactly 3-dB, the possibility exists that the JVC test record is cut to 3.54-cm/s peak velocity instead of 3.54-cm/s RMS velocity. On the other hand, if the difference is something like one or two decibels, then there is probably an accuracy error in one or both of the test records.
.....
The output specs for the Zyx
R100-02/R100-02H
R-100FS(H)/R-100FX(H)
R100 YATRA (H)
R-1000 AIRY3-S(H)
R-1000 AIRY3-X(H)
R-1000 AIRY3/Cosmos-S(H)
R-1000 AIRY3/Cosmos-X(H)
R-1000Sigma-S(H) R-1000Sigma-X(H)
0.24mV (H = 0.48mV) [3.54cm/sec., 1kHz] or 0.34mV (H=0.68mV) [5.0cm/sec., 1kHz]
The link to the page is below. The cartridges in question are the second set of three cartridges in the table...a bit down the page.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
I don't see any mention of test records. These specifications simply state the cartridges' output voltage at stylus tip velocities of 3.54-cm/s and 5.0-cm/s respectively. The voltages increase by 3-dB for the higher velocities because the velocities increase by 3-dB.
What I would like to see is the output voltage from a cartridge playing Band 5 on the JVC test record compared to the same cartridge playing Band 6A on the STR-100 test record. Both of these are left channel signals supposedly recorded at 3.54-cm/s 45-degree velocity as stated on the record labels. They should produce the same cartridge output voltage within a reasonable tolerance of about 0.1-dB or so. Any greater difference would indicate an accuracy problem with one or the other test record, or both.
Best regards,
John Elison
nt
We don't shush around here!
Life is analog...digital is just samples thereof
Output voltage: 0.35 mV by the JVC TRS-1007 standard, measured at 3.54 cm/sec, zero to peak, 45 degrees (normal Lyra measurement scale)
Output voltage: 0.5 mV by the CBS STR-100 standard, measured at 5.0 cm/sec, zero to peak, 45 degrees
From the link below...
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
If Lyra is correct, there is nothing wrong with either test record.
On my STR-100 test record there are only two 1000-Hz test tones, both of which are stated to to have groove velocities of 3.54-cm/s RMS in the 45-degree direction. This is equivalent to 5.0-cm/s peak velocity in the 45-degree direction just as Lyra states. Apparently, JVC decided to cut their reference test tones at 3.54-cm/s peak velocity in the 45-degree direction. The voltages reported by Lyra for the two test records are exactly 3-dB apart as they should be. The only problem is with JVC for not labeling their test record properly and thereby causing all sorts of unnecessary discussion and confusion.
Best regards,
John Elison
Perhaps the JVC test record is labeled correctly but it is in Japanese and we don't have a complete and accurate translation.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
I really don't know the convention for specifying velocities. My feeling is that it should have been labeled either peak or RMS. The STR-100 is labeled RMS so there is no question left unanswered. However, it is clear from Lyra's measurements that the JVC velocities are peak velocities compared to the RMS velocities of the STR-100.
.......
Edits: 05/11/10
I was wondering about the sleeve. The info I found on Yosh's site had an image I believe was from the LP that was in Japanese.
I have no idea one way or the other whether all of these were in Japanese or not. I don't recall ever seeing one in person.
You have the CBS, and I know I have a couple of the Shures and I have seen many others but not the JVC.
Anyway, it wouldn't the first time test equipment came with crappy documentation.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
When I was collecting the data for the Cartridge Database, the older cartridges were particularly interesting in that there was a pretty wide range of "reference" velocities.I suppose having two is better but I doubt that many people really understand the differences between the two.
Thanks for looking at this John,
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
Edits: 05/11/10
I'm just trying to understand the difference.It would be interesting if someone had the JVC record.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
Edits: 05/11/10
I think...;8^))I googled around and found a relatively interesting page below. It lists a lot of intesting information relative to test specs for records and includes information on the velocities in question, standard test records, quoted standards and everything we need to fall asleep on a tough night...just kidding.
Good reference. It looks to be Yosh's page from that other forum.
Ed
We don't shush around here!
Life is analog...digital is just samples thereof
Edits: 05/10/10 05/10/10
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