An appeal to Adjust+ owners who also own oscilloscopes

[ianm0]

The phase measurement provided by Adjust+ has always been a conundrum for me. One can show via electromagnetic theory that the phase between main signal and its crosstalk depends only on the ratio L/R, where L is the inductance of the cartridge coil and R = (its DC resistance + load seen by the cartridge). That ratio at a fixed frequency can be shown to be constant for any cartridge and depends only on its geometry: R is proportional to length of wire in coil, so is the number of turns of coil to which L is also proportional. So I surmise the phase change due to azimuth variation, if truly there, could have a mechanical origin which may be almost impossible to theorize. Anyway I need to verify phase measurements from Adjust+ before I even try. Hence this appeal.
I am asking owners of both Adjust+ and OCR to measure the phase difference between the main signal and its crosstalk using both of these and share the results. Thanks in advance.
Note: Using an ANALOGUE CRO, I measured several cartridges. The phase difference between main signal and crosstalk in each case is very close to zero or 180 degrees, i.e. almost in phase or out of phase. This was collaborated by John Elison (see message #68 of this thread). I have no faith in the particular software CRO on my computer when it comes to phase measurements - they are irreproducible. However, a good digital CRO - like the one used by Elison should have no problem.

 

[J.R. Boisclair]

Hello ianm0,

Stylus zenith error in a horizontally modulated groove causes vertical modulation in which the amplitude of the modulation is logarithmically related to the error. This will certainly influence the phase results in any multivariate test - such as ANY test that takes an electrical reading from the stylus scraping through the grooves. This is why it is so very important to have at least one of the three stylus orientation parameters determined via univariate means FIRST. It gives you a "Rosetta Stone" from which you can have a far higher confidence in the results of a multivariate test. The easiest parameter to align via univariate method is dynamic SRA.

If there is a thread elsewhere on this issue let me know as I'd like to see what is being shared on it.

 

[J.R. Boisclair]

This was collaborated by John Elison (see message #68 of this thread).

hello @ianm0. I would like to investigate this as well. Have you made any progress? Do you have the link to the thread mentioned above?

 

[ianm0]

hello @ianm0. I would like to investigate this as well. Have you made any progress? Do you have the link to the thread mentioned above?

JB:
Here is the link: https://www.audioasylum.com/messages/vinyl/919668/an-oscilloscope-is-simply-a-measurement-tool.
I'm not sure what you mean by "this"? Is it why signal and crosstalk are almost in phase for some cartridges and almost out of phase for others (minority).
I did a rough estimate on the phase discrepancy due to zenith error - based on time difference of the two signals - and the origin of which is electromagnetic (??t). The result is less than 1 deg. That certainly does not account for the phase difference measured with Adjust+. However I don't rule out there may be a mechanical cause, which I do not have the faintest idea and hope others with insight can enlighten. That's the reason behind my plea for verification of Adjust+ phase measurements with a good oscilloscope.

You asked whether I had any further progress. I also did a phase shift calculation of the induced cross talk. The phase difference should be proportional to L/R of the coil carrying the crosstalk. But this ratio should be approximately constant. Reason: both are proportional to the length of the wire in the coil, irrespective of coil geometry and dimensions.

 

[bazelio]

I had tried to correlate Adjust+ to an oscilloscope years ago. The idea was to determine what Adjust+ was actually measuring. I could never figure it out. On the oscilloscope, I could visually see the crosstalk signal being close to 180 degrees out of phase. Maybe 160 degrees by just eyeballing it. But Adjust+ was reporting near zero phase error. I also could never find a positive correlation between Adjust+ phase error and sound. Not to my ears. But after switching to AM, what I found was that reducing measured distortion on the VTA track by adjusting cartridge zenith always correlated - lower distortion on this test equalled better sound. Always. For me.

 

[ianm0]

I had tried to correlate Adjust+ to an oscilloscope years ago. The idea was to determine what Adjust+ was actually measuring. I could never figure it out. On the oscilloscope, I could visually see the crosstalk signal being close to 180 degrees out of phase. Maybe 160 degrees by just eyeballing it. But Adjust+ was reporting near zero phase error. I also could never find a positive correlation between Adjust+ phase error and sound. Not to my ears. But after switching to AM, what I found was that reducing measured distortion on the VTA track by adjusting cartridge zenith always correlated - lower distortion on this test equalled better sound. Always. For me.

One thing I never understood is the phase difference measured by Adjust+ ranges from 0-180. Why not 0-360 or -180 to +180 deg? Traces shown on an oscilloscope are definitive.

 

[mtemur]

I had tried to correlate Adjust+ to an oscilloscope years ago. The idea was to determine what Adjust+ was actually measuring. I could never figure it out. On the oscilloscope, I could visually see the crosstalk signal being close to 180 degrees out of phase. Maybe 160 degrees by just eyeballing it. But Adjust+ was reporting near zero phase error. I also could never find a positive correlation between Adjust+ phase error and sound. Not to my ears. But after switching to AM, what I found was that reducing measured distortion on the VTA track by adjusting cartridge zenith always correlated - lower distortion on this test equalled better sound. Always. For me.

+1

 

[bazelio]

One thing I never understood is the phase difference measured by Adjust+ ranges from 0-180. Why not 0-360 or -180 to +180 deg? Traces shown on an oscilloscope are definitive.

I think it's just an absolute value thing, so to speak.

 

[ianm0]

That's what I thought too. I did ask Dr Feikert and was not given a direct answer.

 

[bazelio]

That's what I thought too. I did ask Dr Feikert and was not given a direct answer.

I've asked Feickert several questions and he refuses to answer any of them.

 

[Calle_jr]

I am asking owners of both Adjust+ and OCR to measure the phase difference between the main signal and its crosstalk using both of these and share the results.

For Adjust+, it is a strict mathematical exercise.
1kHz Left and Right waveforms are being measured. An FFT produces Real and Imaginary voltages at 1kHz. The crosstalk magnitude and phase relative to the main signal are being calculated.
That’s it!

This means, Adjust+ will only show tolerance deviations in the coils. It will not show tolerance deviations in the cantilever or stylus assembly.