How to use Oscilloscope to refine Azimuth and Anti-skating on a phono cartridge

[docbob52]

Does any one have a definitive and complete answer on how to do this using test tones from a record?  I see partial answers using one or two channels  followed by much speculation leading to much confusion on my part.  I have a dual channel scope and have finally mastered the basics of the scope (with Doc's and others help on the forum).

All advice is appreciated

 

[Doc B]

For azimuth you use the X-Y display (plug both channels in to a dual trace scope and set it to XY) and adjust the cart using a sine wave tone. You are looking for as close as possible to a 45 degree diagonal line that slopes low left, high right. As it gets further out of azimuth the line becomes a fatter and fatter ellipse.

 

[docbob52]

Thanks Doc.  Is the 300hz tone on the  HFN test record a sine wave?

 

[Doc B]

No that's for a different test procedure. That is a L-R tone. To use that you would mono the signal tones from the two channels and then adjust az for minumum output. Doesn't necessarily require a scope, but you could use one for the job. For what I am suggesting you would want a regular tone with both channels in the same polarity, and you need left into one scope channel, right into a second scope channel. You could use a standard test band with a steady 300Hz or 1kHz tone.

 

[docbob52]

Thanks so much Dan.  You made it easy to understandand And I  can do it on my dual trace scope.  The diagonal line resultant from the X-Y function would indicate at the ideal 0 deg phase shift.  Does this mean you are balancing the cross talk between the channels or equalizing the output of both channels for adjusting the azimuth?


For adjusting the anti- skate,  what should be the procedure ?

 

[Doc B]

With respect to azimuth You are getting the two channels in phase. If you switch the scope to the regular dual trace display you can see the two sets of sine waves shift left and right slightly with respect to each other as you adjust the azimuth. The perfect 45 degree line (which is almost impossible to get absolutely perfect) corresponds to the peaks of the two waveforms being perfectly lined up with each other. If it is out of phase the line becomes an ellipse. I believe that the procedure is similar to adjust antiskate but that you use a laterally cut groove and the difference that creates the deviation from a 45 degree line is crosstalk rather than phase. But I am not particularly well versed on that.