Phono Cartridge Response Measurement Script

[Thomas_A]

Same same.

 

[JP]

Can you give me your raw layback (no processing)?

 

[Thomas_A]

Can you give me your raw layback (no processing)?

Recorded with my preamp/RIAA:

Dropbox

www.dropbox.com

 

[JP]

I reduced level ~20dB to prevent clipping, applied inverse RIAA:

(setf *track* (biquad-m *track* 7.9682567668766300E+00 -5.2724672933908900E+00 -1.4469430767688700E+00 1.0000000000000000E+00 3.6557310000000000E-01 1.4996620000000000E-02))
(biquad-m *track* 1.10057904093330000E+00 -6.65301031771105000E-01 -4.30266896696176000E-01 1.00000000000000000E+00 -5.75527420000000000E-01 -3.79604780000000000E-01)

Then applied the doubled filter:

(biquad-m *track* 0.73137993061956 -0.39063797071820 -0.27569578143734 1.0 -0.59106473412185 -0.39977762693709)

 

[Thomas_A]

Oops. I was too fast copying the bi-quads in the spoiler..post 5. I forgot one part.

But your result looks good.

 

[Thomas_A]

Ortofon vs. the CA-TRS1007 at the same loading. Could try my Flokason copy as well.

 

[JP]

So we solved it.

 

[Thomas_A]

So we solved it.

You did!

 

[JP]

I wouldn't have looked had you not prompted on the squared LF EQ.

 

[Thomas_A]

I did a layback with a DL-1000A because it's the flattest cartridge I have. The telltale here is the response from 800 Hz to 1 kHz, with the double-pole filter being flat and the squared filter not. The tails of the LF corrections are fully settled by 3 kHz.

The dip to -1 dB around 12 kHz smells, but I don't think it's caused by the LF filter error during cutting. If I put filtering in the script for this record, it would be the doubled filter and not the squared.


View attachment 522888

Is it possible for ypu to plot the DL1000A with both JVC TRS1007 and the ortofon left and right channel separately? Normalized at 1000 Hz and range 800 Hz-20000 Hz?

 

[Thomas_A]

Again a test of the CA-TRS1007 vs. the Ortofon. Track 1&2 of the CA-TRS1007 (blue) and track 3&4 of the Ortofon (red). It is a bit of channel variation, but the difference around 10 kHz is between 0.5-1 dB. Otherwise the compensation is worthwhile, and makes the record at least useful for the script. With the reservation of the drop. Both sides of the Ortofon was in principal identical, as was the Flokason test record (which is the same origin as the Ortofon).

Left channel:

Right channel:

A final note; the point of normalisation is also affecting the results. Error in the lows or in the highs? Not sure.

 

[JP]

While working on the groove calculator, something dawned on me while working through how to show distortion in a meaningful way. For the frequency response script, by the nature of the test records not being cut with traditional RIAA, our second and third harmonic plots are "pre-RIAA". This means that with traditional program material where RIAA is applied in playback, above approximately 2.5 kHz the second harmonic would be about half and the third harmonic would be about one-third of the raw electrical response from the cartridge.

I'm not sure a lot of folks understand that.

 

[Thomas_A]

While working on the groove calculator, something dawned on me while working through how to show distortion in a meaningful way. For the frequency response script, by the nature of the test records not being cut with traditional RIAA, our second and third harmonic plots are "pre-RIAA". This means that with traditional program material where RIAA is applied in playback, above approximately 2.5 kHz the second harmonic would be about half and the third harmonic would be about one-third of the raw electrical response from the cartridge.

I'm not sure a lot of folks understand that.

I would say that I use it mostly to compare results from performance/wear. Alll my JICO SAS/B stylii have shown the lowest distortion when new, and then degrade over time.

 

[Balle Clorin]

I wonder wy I get so wildly different plot with the 18.7 plot and Web app.. WEB to the right. plotting two left channals to compare

 

[JP]

Has to be a setting. Web runs the same 18.7.0 script.

 

[Balle Clorin]

Support added for Technics SFC-TR100 test record. Works for the original and Issue 2 which has voice prompts. These records start with a 1kHz reference tone before the sweep pilot tone - don't include the reference tone in the recording.

Technics SFC-TR100

Documents

docs.myhi.fi

Now you made me buy version 2 too…

 

[JP]

You want me to add CTC-300 support? I love spending your money

 

[Balle Clorin]

Not a problem, I have too much money, I….
I have decided not to by Ortofon TC-3000..CTC-300 I cannot Find with Google

 

[JP]

 

[JP]

TC-3000 is spots IIRC? I have it but haven’t looked at it for years.