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Frequency Response Test Records

OP
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Balle,

I only own the CBS STR-112. With the AT33-PTGII I measure following values:

1682874959483.png
 

JP

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Which version STR-100?
 

JP

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I thought Balle said STR-100. I remembered incorrectly.
 

Balle Clorin

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Balle,

I only own the CBS STR-112. With the AT33-PTGII I measure following values:

View attachment 282625
Strange I Get 30% on +6 on STR 112 on the same cartridge.. and 6-7% on STR-111. Using REW with Generator set to 400hz :4000hz 4:1 and import file in RTA window. Wye record was sealed NOS and supposedly unused. Recording flat with no RIA

If I may ask, how does your FFT look like?

Not sure why REW reports -20db sidebands at F2-F1 and F2+F1 as about 30% IMD( and not 10%) .

1682927243735.png




REW gives sidebands -20db below F2
1682926912082.png
 

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OP
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stereoplay

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Balle,

sorry for confusing you. No worry about that high figures. I showed the FIM measurements, which is no AM modulation.
It exists a mathematical conversion (Bessel) to the IM you measured with REW. But REW is not best to measure IMD your way, because you don't use the built in signal generator. Slight frequency deviations and speed changes leads to wrong calculations. See the picture below (f!=4000Hz)

I show you both measurements FIM and IM in comparison (Ortofon Red):
Screenshot 2023-05-01 13.16.16.png
 

Balle Clorin

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Can you please tell what I should use and how to calculate the «correct» IMD, ?
I think some old Issues of American Audio state to use a IMD meter and to look at the first sidebands.
Many Thanks,

PS cannot find any definition for FIM
 
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OP
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stereoplay

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First I would measure the 400Hz/4KHz components exact frequency. If it is e.g. 390Hz/3950Hz use this as the two "generator frequencies" in the REW settings and measure again.
This could maybe help.

FIM was used in Germany as a kind of standard. It can be measured with the EMT 424 --> https://emt-archiv.de/emt-424/

I have only German descriptions:

https://www.radiomuseum.org/forum/messschallplatten.html here under Verzerrungs-Meßschallplatte nach DIN 45 542


and as a example:
1682959904549.png
 
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Balle Clorin

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Thanks I will try.. did reduce IMD form 30% to 10%
1682959273736.png

I once had this software the could build electronic blocks and simulate them and give an output, cannot find it of remember the name

but what would be cool to have is this
1682958790878.png


1682958726897.png
 
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morillon

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and me a new ttr117 just to check if my intuition concerning the possible interest of his "tri-tons" for the experiments concerning the observation of the wear of the thread "on the side"..( and the "ccif " of the srt-14a)
I look very stupid when I see what I already had on the shelves...""one more""..
hihi
:oops::p
 

USER

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Jøssenamn ,, How did you manage to Get hold on that. !!
I was able to get one of two NOS that popped up on discogs a few weeks ago. There is a used one there now (VG+ condition, seemingly well used) but I don't know if I'd go for it as shipping is expensive to the US.

 

DrCWO

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Your post shows different measurement results for ShureV15 V-MR and CA-TRS-7001.
I like to know what the reason for the differences is? I cannot read that out of the legend.
As I am waiting for my CA-TRS-7001 to arrive and I also got a Shure V15 V-MR with a fresh NOS stylus ($$$ ouch) I like to know what can be achieved if the pickup was adjusted correctly.
Best DrCWO
 

USER

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Your post shows different measurement results for ShureV15 V-MR and CA-TRS-7001.
I like to know what the reason for the differences is? I cannot read that out of the legend.
As I am waiting for my CA-TRS-7001 to arrive and I also got a Shure V15 V-MR with a fresh NOS stylus ($$$ ouch) I like to know what can be achieved if the pickup was adjusted correctly.
Best DrCWO
I believe the dip at the end of the FR on that measurement is related to a bit of warping issue the record has. Flattening it with a record flattener should help. This happens with test records unfortunately as it is a negative issue of the medium. You can't expect perfect results but that's ok.

Also note that there *may* be some Shure V15 V-MR cartridges (styli) that exhibit a bit of a downward slope. I have seen this when comparing over 6 styli. Two distinct patterns. It may be related to manufacturing changes. I will test this again one day in the future with my current, finalized set up so it is just a theory for now. The above is not that phenomenon however.
 

Balle Clorin

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IMG_0970.jpeg
New arrival. Denon XL-7004/7005/7006.According to some sources XL-7004=XG-7001


Looks interesting with 30 page booklet , maybe I can run some sweeps tomorrow.

IMG_1992.jpeg


Sweep has low turnover frequency of 250hz acccpring to Google translate
IMG_1994.jpeg


Booklet shows a plot of skating force across record that I have not seen before..
IMG_1996.jpeg
 
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