Checking Cross talk with Oscilloscope and other things

Entre' EC-20 Re Tip channel balance and Cross talk
Left top , right bottom.

41379816152_b0ff99cfac_b.jpg


Left signal with Right crosstalk

27550530688_2c28670e16_b.jpg


Right channel with Left Crosstalk

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Very Happy with the results of this MC cart re tip. This re tip is actually using the original Cantilever I removed from the EVG 707-DE .

I must say this is a really nice sounding LOMC cart. It's mu first experience with a Low output MC I have a Sumiko EVO III HOMC so this is a little different.
I really like its character, but maybe its the MC section of the Yamaha A960 I like.

Athanasios
 
Entre' EC-20 Re Tip channel balance and Cross talk
Left top , right bottom.

41379816152_b0ff99cfac_b.jpg


Left signal with Right crosstalk

27550530688_2c28670e16_b.jpg


Right channel with Left Crosstalk

27550530678_087326632a_b.jpg



Very Happy with the results of this MC cart re tip. This re tip is actually using the original Cantilever I removed from the EVG 707-DE .

I must say this is a really nice sounding LOMC cart. It's mu first experience with a Low output MC I have a Sumiko EVO III HOMC so this is a little different.
I really like its character, but maybe its the MC section of the Yamaha A960 I like.

Athanasios

There is some azimuth adjustment needed here if you trust the test record.
 
The for the trade standards back in the 70s were the Shure, AT and CBS test records along with the cartridge analysers from Shure and AT.

I have lost mu CBS test records from 40 years ago but have made the comparisons between my 5 or 6 Shure and AT test records and the HIFI news LP. While I have the UTLp record I have not made a comprehensive comparison between it and the others......I do not rember any red flags about it's accuracy but did question it's hyperbole and usefulness compared with the HIFI news record.

As I posted in the past using the computer based scope, and then doing the math to convert RMS volts to dB volts I found that the digital program transferred consistently to the dB volt meter which is part of the Shure test analyser.

A conventional scope shot monitored at the same time showed no great discrepancy, although by it's very natural a traditional scope demands a judgement call by the
operator.

The testing procedures are tried and true.......interpreting the measured results, diagnosing so to speak the auditory judgements vs the measurements, or more specifically what the measured results tell us about the plus or minus judgements about what listeners call good, better, or best sound is where it gets really interesting.
 
Nice job. Though cartridge dependent, I'm curious how close one typically gets by just setting the cartridge square to the record. Or, conversely, when you set up with the scope for excellent crosstalk, what does the cartridge look like when done?
 
Nice job. Though cartridge dependent, I'm curious how close one typically gets by just setting the cartridge square to the record. Or, conversely, when you set up with the scope for excellent crosstalk, what does the cartridge look like when done?

With a quality cartridge and tone arm it looks quite parallel to the record surface.....but the difference between one channel being at 28db and the other at 10 is but a few degrees...... not really detectable.
 
The UATL is not ideal for azimuth. I've compared this with the the Tacet, the HFNRR, and the Ortofon. The Ortofon is not useful for e.g. accurate fr response, but the left-right test is the best of them all.

What makes that so?

Nice job. Though cartridge dependent, I'm curious how close one typically gets by just setting the cartridge square to the record. Or, conversely, when you set up with the scope for excellent crosstalk, what does the cartridge look like when done?

Well with both of these carts I have them on TT's that really don't have adjustment for azimuth. The Acutex is on an AR XA with stock type head shell. That one I was able to adjust azimuth right on the stylus assembly . But there is also a little play by twisting the head shell in the tonearm socket, but it doesn't hold well. It might be able to adjust a bit more
at the arm tube pivot junction as its held by a screw. But I did not attempt that.

The Entre' I have on a Dual 1019 . So that would have to be shimmed. The scope shots there are with out any adjustment for azimuth, that is why I was so pleased with the scope results as I got the re tip as close to perfect as possible by eye with the only aide a magnifying lamp and my Loupe' . But now looking back I think I did have to shim the cart a bit as it wasn't square in the head shell.

This is pretty off-topic, but what music would you say your Acutex is best suited to?

I listen to all types of music, Mostly Rock/Alternative , Punk , some Greek , and Jazz. I really like the Acutex on Jazz though . But it does well with everything. I'll put it this way, I wont change it after listening to Jazz, I just keep rocking through my LP's

Athanasios
 
What makes that so?

If I use the UATL I will get some results like this:

Sk%C3%A4rmavbild%202018-01-02%20kl.%2018.47.10.png


And I can adjust for equal crosstalk using azimuth, but I never get anything better than -28-30 dB or so

If I use the Ortofon I get something like this:

Sk%C3%A4rmavbild%202018-01-02%20kl.%2018.47.27.png


And I can adjust for equal crosstalk and get something like -40 dB

So it means that the UATL has some signal recorded in the quiet channel even though it should be silent.

With the Ortofon the cartridge looks perfectly symmetric, while with the other records including the UATL it will tilt 1-2° in one or the other direction.

So conclusion is that with the Ortofon gives the lowest crosstalk, and that is a sign that the other records do have some signal recorded that should not be there. So I cannot trust that this give me correct adjustment.
 
If I use the UATL I will get some results like this:

Sk%C3%A4rmavbild%202018-01-02%20kl.%2018.47.10.png


And I can adjust for equal crosstalk using azimuth, but I never get anything better than -28-30 dB or so

If I use the Ortofon I get something like this:

Sk%C3%A4rmavbild%202018-01-02%20kl.%2018.47.27.png


And I can adjust for equal crosstalk and get something like -40 dB

So it means that the UATL has some signal recorded in the quiet channel even though it should be silent.

With the Ortofon the cartridge looks perfectly symmetric, while with the other records including the UATL it will tilt 1-2° in one or the other direction.

So conclusion is that with the Ortofon gives the lowest crosstalk, and that is a sign that the other records do have some signal recorded that should not be there. So I cannot trust that this give me correct adjustment.


But if you really think about it it doesnt matter if you try to get each cross talk equal. Unless the signal in the supposed null channels are not equal.


Athanasios
 
But if you really think about it it doesnt matter if you try to get each cross talk equal. Unless the signal in the supposed null channels are not equal.


Athanasios

Well that is the purpose with azimuth to get the coils in the cartridge symmetric to the 45° grooves. Usually you can fine adjust within 1-2 degrees and lower and equal the crosstalk by 5-10 dB, which is significant. You also need to look at the phase.
 
And if I get different results with different test records, I would trust the one with the lowest crosstalk signal, as mentioned.
 
You also need to look at the phase.

XY does a nice job of that.

The issue is the test records and their consistency, accuracy and condition. I've got a half dozen or so and they vary considerably. The HiFi news one had such potential, but the QC wasn't there.
 
Using the AT or Shure analyser along with their coresponding test records back in the day, the typical crosstalk numbes were in the 23 to 27 dB range for cartridges that sold in the 75.00 to 150.00 range, approaching the 32 dB range in the 250.00 price range and in a few rare cases approaching 40 dB in the high price ranges.

Back in the late 70s and thru the 80s doing 3-4 setups a day was common. There were a lot of name brand, popular mass market cartridges that struggled to get 20 dB of seperation......not too far way from mono and in most cases worse than FM.

Remember you are observing how much of the full signal is leaking into the other channel so there will always be some residual, you are adjusting the contact with the groove walls in ALL it's directions as it pivots in the groove.

What measurement device are you using to get your voltages of 40 dBv?
 
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What measurement device are you using to get your voltages of 40 dBv?

If that was adressed to me, I use Amadeus to measure the average level in the channels at 1 kHz. I also filter out noise and low frequencies to just look at the 1 kHz signal. I get around 35-40 dB with my Shure V15Vx/JICO SAS. With the original Shure I did not get more than 25-30 dB.
 
Amedeus is what?

A V15 type 4 or 5 when new struggled to exceed 25 dB using either the Shure or AT test records and analysers. The image was tightly packed in a narrow presentation less than 2/3 s the width of the speaker seperation. This tightly packed sound stage pleased some older clients but was too old school hifi for many.

The AT32 MC of the same time frame presented a sound stage that exceeded the width of the speaker system by a few feet on either side....so maybe 25 % wider than the speaker width. This of coarse thinned out...spread out the detail inside the sound stage. This type of sound stage pleased most of the new audiophiles. It measured 38 dB seperation that was the highest number I had ever measured which was quite remarkable since the Neuman cutter head was spec'ed at 35 dB.

I had to regularly sample and test, sort through, dozens of Rep samples to find cartridges we would represent and their atributes. T'was a tough job but somebody had to do it.

It was not until I had a chance to install and measure three of the custom made prototype MCs made for the president of McIntosh Labs that I found a cartridge that exceeded 40 dB.

In later years the Sumiko MCs and the ATOC9 approached the 38 dB mark.

It always piqued my curiosity why some listeners were so adament in what they enjoyed listening to, in that what they considered "better".

As usual it always came down to communicating with the client and then probing measurements to attempt to understand why they make their choices.

Ultimately our job was to enhance their preferred experience reliably, try to find ways to enhance it.......not make conversions.
 
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