Checking Cross talk with Oscilloscope and other things
- Thread starter Nashou66
- Start date
I have been experimenting with a computer based oscilloscope program that provides a RMS voltage for each channel as well as a peak voltage.
One of my test record alternates frequency sweeps for each channel....this allows the comparison of channel separation at all frequencies and with the cursor set at a frequency the voltages at that frequency will be displayed.
Running this as the scope fed from my vintage Shure Cpek and then doing the math to calculate the dBv it has compared favorably with the indicated voltages taken from the Cpek.
When I have taken it out into the field without the Cpek I have run into issues with some high end preamps tape out over loading the input of the Berringer analog to usb converter......when they say 1 volt input they mean it.....I have yet to make a attenuator for it.
One of my test record alternates frequency sweeps for each channel....this allows the comparison of channel separation at all frequencies and with the cursor set at a frequency the voltages at that frequency will be displayed.
Running this as the scope fed from my vintage Shure Cpek and then doing the math to calculate the dBv it has compared favorably with the indicated voltages taken from the Cpek.
When I have taken it out into the field without the Cpek I have run into issues with some high end preamps tape out over loading the input of the Berringer analog to usb converter......when they say 1 volt input they mean it.....I have yet to make a attenuator for it.
Do you have the other channel as well?
Yes I am aware of that but as I posted above, I will not use the UATLP for this but the Ortofon. And I look more to equalise phase. Stylus is new so I want to play a bit more with it before I settle the final azimuth.
Back when I had to make both empirical and listening tests of cartridges to resell I would always treat each one for evaluation as a complete blank slate cartridge/ turntable setup.
Microscope examination to see what the manufacturer's actual build tolerances were. You would be surprised how many manufacturers couldn't get the diamond mounted straight.
Sort through the supplied instructions to determine the design enginner's recommended tracking force, not the marketing nonsense but what VTF the designers expect to position the generating system in the nuetral location of it's movement.
Once the alighnment would be set, VTF set, a series of resonance, tracking, azimuth tests could be intertwined as the best tracking and channel separations settings could be found.
Then listening could proceed.
Microscope examination to see what the manufacturer's actual build tolerances were. You would be surprised how many manufacturers couldn't get the diamond mounted straight.
Sort through the supplied instructions to determine the design enginner's recommended tracking force, not the marketing nonsense but what VTF the designers expect to position the generating system in the nuetral location of it's movement.
Once the alighnment would be set, VTF set, a series of resonance, tracking, azimuth tests could be intertwined as the best tracking and channel separations settings could be found.
Then listening could proceed.
Yes... QC issues..... I also have Ortofon OM cartridges with slight skewed cantilevers. After seeing the JICO boron stylii in the microscope I got impressed. And it sounds and measures very well.
Yes agreed. On the other hand, I am quite however impressed by those that manage to mount these tiny diamonds with high precision. If mounting precision were related to the price of cartridge or stylus, I would more confident to buy them, but sadly this is often not so.
Made a test with the Ortofon record. I get something like -36 dB for the left to right channel and a whooping -42 db from right to left. So a bit opposite result compared to the UATLP where I get -38 left to right and -33 db from right to left; i.e. results depend on which test record I use.
As I mentioned elsewhere I think however that the record that gives me the lowest crosstalk would be the best to use when azimuth are adjusted for equal crosstalk. Now, I have a Moerch UP-4 Unipivot arm mounted and although I like the low mass and other aspects of it, it is a bit of a pain to set up and adjust. I was thinking of the other Moerch but they are too expensive IMO. Trying to fix up my old Akito arm seems not easy and although bearings can be bought, they are still just ABEC5, and not that good it appears. Also azimuth is not possible to adjust on the Akito arm. I am thinking again to buy a Pro-Ject 9cc. It has the same mount distance as the Akito and the Moerch, ABEC7 bearings, 8.5 g effective mass (a bit high but ok), and adjustable azimuth. The UP-4 settings tend to drift a bit over time, and requires continuous checks.
knockbill
Lunatic Member
Or you can do this !!!!!.................
Nashou
That's my test set up also!!
Can you post a trace of the X-Y plot? I know the math for that but I could never get a good trace on my old analog oscilloscope, probably due to the noisy crosstalk trace. The noise might be from the OCR, so would like to see a clean trace for that.
