ZYX Universe - Unipivot or Dual Gimbal arm

Hi Thom,

Before I start measuring crosstalk, I play a test tone thru both channels and use the balance control to make the measurement the same in both channels. Once I have equal output in both channels, then I measure the crosstalk using the left channel and right channel test tones. I assume that is the coreect way to do it. Yes???

Wally's method does not assume perfect channel balance, in the cartridge or any other component. He specifically designed to avoid that assumption.

He starts by measuring output on each channel. Any imbalance is allowed for in the calculations that follow.

Hi Doug,

I just finished speaking with Wally regarding azimuth and his instructions for adjusting azimuth contained in his Analog Shop Deluxe instructions. Instruction #5 says to play the two channel test tone and use the balance control to set the output of the left and right channels to within 5% of each other. Per Wally, 5% is 1/2dB and is close enough. It would not hurt to make them equal, but Wally does not think that the effort required to make them equal is necessary. Instruction #11 says to keep adjusting azimuth until the crosstalk numbers are equal. Per Wally this is a simplification done to keep the instructions from getting too long. He gave me an example. Assume that you can get azimuth adjusted so that crosstalk reads -26dB and -26dB. You can stop here. However, if you can get crosstalk to read -27 and -29 that is better. However, -24dB and -30dB would be worse than -26dB and -26dB. The key thing for Wally is to reduce the crosstalk without an obvious tilt to the cartridge body when viewed head-on. Wally thinks more than 2% tilt is unacceptable.

Wally agrees his instructions are simplified, but rather than write long, compicated instructions he wants people to call him with questions.

So, to summarize: 1) use the balance control to equalize the output between channels to 5% or less. 2) equalize the crosstalk between channels. 3) experiment to see if by making the crosstalk readings unequal that both crosstalk readings can be dropped to less than the equal point readings.

I hope this clarifies things.

Regards,

Roger

Hi Thom,

I mentioned to Wally Frank Schroder's comment about there being several "null" points for both VTA and azimuth. Wally was of the opinion that if you were setting azimuth with a voltmeter that you would find only one "null" point.

Since Frank sets azimuth by ear, it is quite possible that he hears different "null" points that would not measure as a "null" point on a voltmeter. Food for thought.

Regards,

Roger

Hi Roger,
The reason for the (in some, not all cases)existence of more than one "null" point is the fact that azimuth(crosstalk symmetry) is usually perfected for one frequency only! When you look at the crosstalk figures versus frequency plots of most high quality carts(if such a plot is provided), you will note that the l/r channel curves for the crosstalk are rarely, if ever congruent. As a result you could achieve perfect symmetry for 1kHz(that's the frequency used on many test records) and an uneven figure for, say, 4kHz . Now which is the correct one?
The dhfi "Hörtest-und Meßplatte 2"(long out of print) has crosstalk tests for 125, 500, 1000, 5000 and 10000Hz. This is what I check my "azimuth by ear" adjustment against frequently. When you adjust azimuth by listening it takes all frequencies into account...
BTW,Wally is right, more than 2° tilt to get even(or maximized) crosstalk figures is unacceptable.

I hope this doesn't cause even greater confusion...

Cheerio,

Frank