Step by Step How to Use a Digital Multimeter / Oscilloscope for Azimuth Adjustments


So I did the usual azimuth setup for a VPI using the rod on top of the tonearm groove (method of setting that is included with VPI turntables from factory) on my VPI Classic 3.   I also bought one of those clear blocks on Amazon with the lines so you can get it as flat as you can visually.   It does sound good just doing this but I wanted to go next level and see if I could do it electronically even better.    I have read you can use a digital multimeter (DMM) or oscilloscope to do the adjustments.   I found on Amazon a Hantek 2D42 that has both features and I bought the BNC to RCA connectors for it so I can interface it with my turntable or alternatively the preamp output on my Sutherland 20/20 for boosted signals.
That all being said, how do I use this for setting the azimuth?   I have read you can use either device (DMM or Scope) to do this adjustment but it seems like the directions are pretty sketchy on how to do it.
I looked into buying the Adjust + software but as of August 2021 it isn't available to buy any longer so that isnt an option.
Anyone know how I can use this Hantek to do the testing and adjustments?
Thanks in advance,
Jason
newguru

Showing 4 responses by lewm

Interesting report. My experience was also with a Koetsu, an Urushi. What I reported above was what I observed when I used azimuth to alter channel balance, just to see if what others described was true, that azimuth has very little effect on balance for a very large change in azimuth. It was true; for a less than 2db change in balance, the azimuth needed to be 20-30 degrees offcenter.  But also when I next set the Urushi for equal crosstalk, the cartridge ended up at least 5-10 degrees off top dead center. Being a slave to numbers, I listened to it that way for some time. It never sounded as good as an Urushi should sound (in my Triplanar). When I finally readjusted azimuth so as to approximate a 90 degree orientation, regardless of numbers, it sounded much much better. The obvious problem is that equal crosstalk seems to be a good idea, but if it requires the stylus tip to be engaging the groove at an extreme angle, that is NOT good, either for SQ or for the stylus and your LPs. (Not every sample of every cartridge is going to readout that way, of course.)
Mijostyn, You wrote, "all you have to do is get a test record with a test tone equal in both channels, reverse the leads on one channel at the cartridge, put your meter on AC and adjust the azimuth for the lowest voltage."
Obviously, your method is much simpler than mine, too simple in fact.  First, any channel imbalance will dominate any crosstalk.  So essentially you will be correcting for channel imbalance. Using azimuth to correct for channel imbalance is NOT good, because azimuth has little effect on that parameter, and one ends up with very extreme azimuth angles. (I tried this once just to verify the fact that azimuth does not much effect balance, using my Triplanar.  The cartridge ended up about 20-30 degrees off top dead center to achieve a 1.5 or 2db change in balance.) Second, as you say, your method addresses only one of two possible goals of electrical setting, the choice to equalize crosstalk, L channel into R and R channel into L. It wouldn't work for the goal of "least" crosstalk, where there is no thought of equalizing crosstalk. (I hope that makes sense; think about it.)  In all my experience, if you aim for equal crosstalk (L into R = R into L), that setting is not the same setting as for lowest amount of crosstalk, where equality between the two sides is ignored.  There are whole white papers written by guys who know more than we do about why one or the other goal is "best".  Anyway, I am now a follower of Korf's method; I have ceased even to measure electrical crosstalk.
newguru, Seems you may be correct that your meter is not sensitive enough, but the spec for output voltage of your cartridge (2.2mV at 5/cm/sec) alone is not the final arbiter of whether or not your meter would work.  Because we don't know what is the stylus velocity on the 1kHz test band; it might be 5X or 10X the standard velocity for measuring cartridge output, which would put you at least at the lower end of your meter's sensitivity.  On the other hand, since crosstalk is going to be a tiny fraction of the signal voltage, and since that is what you ultimately will want to measure, you're likely to be out of luck for measuring the crosstalk directly.  That was to be expected, and it is my fault for suggesting it might be even possible without amplification.  So you are going to have to do the measurements at the output of the phono stage or preamplifier. The phono stage provides RIAA correction.  The RIAA curve is flat from about 500Hz to about 2kHz, which is good, because it will be flat (zero correction due to the RIAA filter) at 1kHz.  The output of the phono stage will be in a very comfortable range for either your scope or the meter function. (I gather your Hantech can function both a scope or as a meter.)I recommend that you read this article.  It makes a good argument for the "physical" method of adjusting azimuth.http//korfaudio.com/blog36

With all respect, MC, I have no idea what you are talking about here or how it relates in any way to adjusting azimuth: "The problem with this one, it is like measuring an amp by watts. Do the most watts mean the amp sounds the best? Right. Waste of time."
Setting azimuth by orienting the stylus in the groove so it sits squarely is different from setting azimuth electrically. You seem to know this. There are some very good papers on this subject, and reading them led me to the practice of setting azimuth by the physical method.
However, to set azimuth electrically, you will need a test LP that contains a band that encodes a single pure frequency (typically 1000Hz) in the R channel with no signal in the L channel, and then also contains a second band that encodes the same frequency in the L channel with no signal in the R channel. Shure and probably some other companies made such test LPs. Then you first calibrate your system by setting the signal strength to be equal in each channel. In other words, play the R channel band and observe the db or voltage in the R channel. Do the same with the L channel signal, and set the two to be roughly equal in db. Now play the R channel band and observe the signal strength that appears in the L channel. Then play the L channel band and observe the signal strength in the R channel. Adjust azimuth toward one of two possible goals: equal crosstalk vs lowest possible crosstalk, regardless of equalizing. There is another whole argument about which of those two goals is to be preferred, electrically speaking, because in my experience "equal" is never the same azimuth setting as "lowest". Also, keep in mind the obvious fact that you would like to insert your meter or scope as close to the cartridge output as possible. If you readout at the phono stage outputs, then you are including any inequalities between the two channels of your phono stage in the data.  On the other hand, trying to read the microscopic voltages from an LOMC cartridge directly can be frustrating or impossible if you want repeatable results.  It's easy with high output cartridges and good instruments.