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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
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
24 responses Add your response
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.) |
@lewm is dead right. According to Peter Lederman, matching electronically usually means equalizing channel separation, which is a bad idea which can lead to a poor adjustment. So if you have a high end cartridge, with natural channel separation of say 37dB in one channel and 43dB in the other, you have to cant the stylus at a ridiculous angle to equalize. Ask me how I know. My higher end Koetsu must have been at 10 degrees to equalize channel separation. Sounded terrible. Set optically and then by ear, and the cartridge sounds sublime. And it scarcely wears at all. Assuming I've interpreted Lederman correctly and my observations are not too subjective. Anyway, YMMV. |
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. |
new guru, I use the inexpensive Hantek DSO5072P scope and the Analogue Production test record. It’s a different record, cartridge and phono pre than yours. The crosstalk was 75/150 mv at the phono pre out. It sounded undistorted. Bringing it down to 65/80 mv brought out the magic. The crosstalk signal was easily above the noise at those levels (visual). |
bikerbw, Harry is perhaps the last person you should be taking advice from. He is obviously not familiar with mounting jigs, robots and RF activated adhesives. The cartridge manufacturers to not manufacture their stylus assemblies. They buy them from a limited number of suppliers. They do orient the cantilevers in the motor assembly and are responsible for the final orientation. This is done with a grid under magnification. My experience is obviously with a limited number of cartridges but I do examine all my cartridges under magnification when they are new and for the last 20 years all of them have been on the money. The glue technique is being used because cantilevers have gotten thinner and the materials are difficult to drill making glue a better choice than holes. It also puts less mass at the end of the cantilever for better tracking. The only downside is that on rare occasion a stylus goes MIA. |
On YouTube on the VPI channel, Harry did a minor rant ("Chat with Mat & Harry EP-2-4-6-21") complaining about cartridges that glue their styli onto the cantilever as opposed to drilling a hole and inserting the stylus, ensuring that the stylus is at a 90 degree angle to the cantilever. According to him, cheap/expensive cartridge, doesn't matter - they're usually always slightly askew forward/backwards/sideways by some amount if they're glued. Kinda funny since they make a big deal about laying that rod in the slot on top of their head shells for setup. The Analog Planet procedure will get you there kinda, as you might find the values bounce around a little so you have to make a judgement call; he also suggests building a DIY box (see link above). Probably easier is the Fozgometer but they're hard to get at this point in time, and there's times where the meter bottoms/tops out and is less useful. I've seen mention of using an oscilloscope (and again, Analog Planet alludes to this way) but you have to learn to read/operate one if you don't know how - might be easy, don't know. |
Read this. https://www.analogplanet.com/content/crazy-little-thing-called-azimuth-part-2 Pretty straight forward. There is a bit of math involved, some measuring and the conversion of numbers from a chart. Works like a charm. You will need a test record with a left/right dedicated channel of a 1k tone. If you do this, you will get the azimuth set perfectly. |
I like this product. It works better than anything else I have tried and makes the cartridge setup task a breeze. It definitely works better than what you are attempting, check the web page for why. https://www.analogmagik.com/product |
Newguru, 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. Easy peasy. That gets your cartridge electrically oriented. The problem with this is that the physical azimuth may be different to one degree or another. If the stylus is not perfectly perpendicular you will be increasing record wear. Which is why many of us visually orient the stylus perpendicular to the groove and forget about electrical orientation. The best cartridges are very close so perpendicular orientation of the stylus gets you very close if not right on electrically. I prefer to protect my records. I can do this visually put putting the stylus down on a mirror. In good light the stylus and it's reflection will form an hourglass. You adjust the azimuth until the hourglass is perfectly symmetrical. You can use loops or some other form of magnification if you like. People who think they can do this listening have an inflated sense of self worth. They can not but, it is their records and they are more than free to ruin them. |
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." |
So lewm, regarding your response, I have in my hands the Acoustic Sounds test LP already so I can do the stereo, left and right channel 1K hertz test tones. In your post you said, " 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." Based on this, with my Hantek, I'm wanting to use it in the oscilloscope or digital multimeter mode? I dont know if it is sensitive enough to read out the turntable directly or not. My cartridge is the Soundsmith Zephyr II which is a low compliance, high output cartridge. Output on the spec sheet is output voltage of > 2.2 mV @ 5/cm/sec. This is where I'm technically inept as far as knowing if that is enough for this Hantek to read out at the turntable or not. I'm guessing it wont go low enough as it says, " VOLTS/DIV Range: 10mV/div~10V/divat input BNC ". This is 2.2mV output so lets assume I have to measure out of the Sutherland 20/20 outputs instead to get readings. |
You guys seem to understand there are two different ways of setting azimuth. What you are missing is what this means: The sort of absolutely precise azimuth you are after cannot be achieved via any sort of observation other than listening. The two methods everyone uses are 1) Observing the angle of the stylus in the groove. This is what the vast majority recommend. Get a USB microscope. This is indeed great and wonderful for getting your stylus geometrically aligned for tracing the groove - of a static, stationary LP. The stylus sticks out from the end of the cantilever. Playing a record exerts lateral forces that torque the cantilever. Everything from the stylus to the cantilever to the cartridge body to the head shell and on down the line starts oscillating like crazy. If you could see it in high speed slo-mo you would freak. You would also shake your head at the futility of observing the static state. and 2) Observing generator voltages. This is the electrical observation you are asking about. In this one, which I would by the way say is arguably more relevant, the observation is to get a voltage as ideal as possible. 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. This one will at least give you a fighting chance of getting really good separation, which will probably lead to a bigger wider deeper sound stage. Probably. But no way to know for sure. Why? Because of #1. What if the electrically correct azimuth results in a slightly different stylus azimuth? What then? Which one do we use? Split the diff? No. We listen. Listening is the only observation that sums all these and more into one coherent whole. Same for VTA, VTF, and all the other stuff too by the way. Just every once in a while instead of just saying so it is nice to let the folks know I know all this tech stuff too. Before you discard something it is always best to know exactly what it is and why it is okay to discard it. |
Excellent info provided! FWIW, it is advisable to use the same preamplifier channel for measuring the crosstalk levels of both channels in order to minimize electrical errors. Unfortunately this requires swapping Input channels between the testing of R/L tracks. Also, most digital level measuring devices utilize a sample hold function. It is highly advisable to use this “Hold” feature as it allows for dismissal of artifacts by observing ONLY the low capture and tossing out Average & High level readings. As stated, the objective is to obtain as low and as equal crosstalk levels as possible between channels by rotating azimuth. Pay attention to anti-skating & pray for symmetrical channel separation of your pickup’s coils. If all else fails, adjust by ear for minimum sibilance while enjoying increased resolution. |
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. |