I first realized the importance of proper azimuth adjustment when someone demonstrated it to me using his Triplanar tonearm. From that point forward, I lusted for a Triplanar. For a very good treatise on azimuth, how to adjust it, why you are adjusting it, what to expect, etc, I recommend a search of the Vinyl Asylum archives for long posts by B Kearns and by V Khomenko (sp?). Those guys are my bible on this subject.
By the way, I own a now antique Signet Cartridge Analyzer which, if you have the right test LP and a Triplanar, makes setting azimuth a breeze, using the direct output of the cartridge itself, which eliminates the possible effects of downstream amplification. But the Signet does not quite have enough input sensitivity for a modern LOMC cartridge output. It needs an antecedent gain stage. |
Dear Teres, You make a good point, mostly because with most all the cartridges that I have ever bothered to align electrically, there IS no one "correct" setting. Usually I have ended up choosing a setting that gives seemingly the least possible crosstalk in each channel, but as those two values (R into L vs L into R) are virtually never exactly equal, one still needs to use one's judgement. I guess I just don't trust my ears enough to do it all by ear. I generally start with an electrically determined setting and then fiddle with it a little more "by ear". |
Dear Hiho, I am not sure what you mean. Any well designed tonearm should have no play in the bearings, regardless of the offset angle. Unipivots are uniquely likely to induce a variation in cartridge azimuth during play, because they can potentially rotate around the pivot, and need to be designed so as to avoid or reduce that problem, vis the Graham. But the prime reason for a need to adjust azimuth is the variability among cartridges in the accuracy of the alignment of the motor with the external boundaries of the cartridge body. If that were always perfect, one could just align with a mirror. Possibly I have misunderstood you, and if so I apologize. |
Essentially, I think Hiho is saying that to adjust azimuth without altering VTA, the adjustment must be made downstream from the ~23 degree offset angle that is typically built into the geometry of fixed bearing tonearms. (It's not always 23 degrees; I own two tonearms, the Kenwood L07D tonearm and the Dynavector DV505 where that angle is less than 23 degrees.) If you adjust azimuth by twisting the arm upstream from the bend, then you are also changing VTA. Is that correct, Hiho?
Never having seen any of the tonearms Hiho mentions as exceptions, I don't readily understand how they work, unless the headshell itself twists about its own axis, as in the case of a removable headshell with built-in azimuth adjustment capability. The newer Reed tonearms also avoid this issue by allowing azimuth adjustment right at the headshell, but this adds several grams in terms of effective mass. |
Dear Dr. Cilantro,
What Doug said. Azimuth is about crosstalk between channels, the amount of the signal in the L channel that appears in the R channel, and vice-versa. It is not about channel balance. In fact, even at extremes of azimuth, the voltage output per channel will change very very little, by about 1db in my actual experiment.
Your friend, Dr. Habanero |
The Shure and Audioquest test LPs, both of which contain bands for setting azimuth in conjunction with the Signet Cartridge Analyzer, generate a pure test tone of 1kHz, first in one channel only and then in the other channel only. I think anywhere from 500Hz to 2kHz is a good average frequency representative of "music". Otherwise, one would indeed go nuts with this azimuth thing. Indeed, it may be too late for all of us. |
I think this is what it boils down to. Please anyone correct me if I am off base:
(1) You need a test LP that has a band where signal of a known frequency is recorded for one channel only. Lets say it's the R channel. Play the band and measure V in the R channel. Now play that same band and measure V in the L channel. That V represents crosstalk of R channel information into the L channel. The difference in V can be converted to db. Formulae are on the internet.
(2) Do the exact same thing, only this time play another band on your test LP that drives only the L channel at the same frequency,. Measure V in the L channel and V in the R channel and again calculate the difference in db.
(3) Adjust azimuth so that you get the largest possible absolute values of db for both sides. It's always a compromise. |
Ideally, you would measure the voltage output where the cartridge attaches to the phono stage. This is really unlikely to work well for the unamplified signal direct from a LOMC cartridge, so the next best thing would be to measure the voltage at the output of the phono stage. I personally would not do it at the output of the amplifier, as someone else suggested further up the thread, because there are so many other variables in the chain that could lead to an inaccurate idea of what the cartridge is actually doing. If you have a discrete phono stage, put the red lead into the hole for the center pin of the RCA plug and your black lead on ground (the outer barrel of the female RCA plug or the chassis, at the output of the phono stage). If you have a built-in phono stage in your linestage, then you might have to take off the casing and find the leads that go from the phono section to the linestage section. |
Dear Doug, the OP asked how to do it with a multimeter. And that;s the question I tried to answer. Such devices do not have filters, true, but I was just trying to describe how one could do it with HIS tools, not the best way possible. Also, it is not far-fetched to assume that surface noise in the unmodulated groove wall would be about the same for the two bands on the test LP needed to make the determination and would hence cancel each other out, give or take a db here or there. The result would be a falsely high idea of the amount of crosstalk but it would still permit adjustment to obtain minima.
In reality, to adjust azimuth I have only ever used my Signet Cartridge Analyzer and my scope occasionally plugged into it. (It has a scope output.) I am not really familiar with these new fangled devices made by Wally, Dr. Feickert, etc. Do they utilize the amplifier outputs? Do you personally do it that way, notwithstanding that you do it by ear as well? After all the brouhaha around azimuth here and on the Grandezza thread, it is interesting for me to learn how those who have the luxury of azimuth adjustment actually do the adjusting. |
Dear Bifwynne: You wrote, "What I don't know is whether the cartridge is operating at optimal channel balance".... I am guessing that this was just an unfortunate choice of words. Azimuth has very little effect on "channel balance", as that term generally refers to the matching of the output voltages of one channel vs the other. Azimuth mainly affects crosstalk. You probably knew that.
It's funny for me to look at my old posts on this thread. When the Triplanar was my main tonearm, I was an azimuth junky. I still own the TP and love it, but I am also using a few other tonearms that do not allow for azimuth adjust, and I find that life is OK without worrying about it at all. Maybe my capacity for anal behavior is diminishing with advancing age. Other improvements I have made to my system since 2010 completely swamp out any effect of fiddling with azimuth. So maybe also I am too blissful. |
