AnalogMagik Tutorial 9: How to Set Azimuth LR & VTA/SRA on Your Cartridge using the Combined Function
(For AnalogMagik Version 2 Users only)
Combined Azimuth L/R & VTA/SRA IMD% Test
AnalogMagik Version 2 is the world's first tool to allows user to adjust Azimuth Left and Right channel together using 1 signle test track. In addition, the Vertical Tracking Angle test track has also been combined together with Azimuth.
Users can now perform Azimuth L/R adjustments and VTA together, ON-THE-FLY, in one go.
Please begin by reviewing the concepts presented under Tutorial (3) Azimuth, and Tutorial (4) Vertical Tracking Angle.
Azimuth refers to the horizontal balance of the cartridge when viewed from the front. This, in turn, determines the horizontal angle the stylus sits on the record groove. When you adjust azimuth by rotating the horizontal level of the cartridge body, you are actually adjusting how the stylus sits in the record grooves.
Vertical Tracking Angle, colloquially, refers to the horizontal angle of the armwand when viewed from the side. But to be specific, it actually refers to the angle between the cantilever versus the record surface, this in turn determines the Stylus Raking Angle of the stylus in the groove.
The Azimuth and VTA adjustment process always begin with visual methods. Tools such as the Acoustical System SMARTStylus (an acrylic block with grid lines), bubble levels, or high magnifying USB Microscopes offers an excellent starting point to "approximately eyeball" a position which is an approximation assumed to be the optimal.
However, visual satisfaction can never be the final benchmark or an "assumed" optimal postion becuase, (1) eyeballing is only possible in a static position. As soon as the record spins, the dragging force exerted on the cantilever damper will cause the dynamic position to change. Whatever you assumed to be the optimal static position will immediately change as soon as the record spins.
(2) Eyeballing also assume a perfect viewing angle. In reality, tilting your head by 1 degree will distortion your actual viewing angle due to parallax distortion. Some use USB Microscopes to magnify the stylus on a computer screen, upon which arbitrary lines are drawn and are assumed to be the single contact point in a static position.
(3) AnalogMagik's setup philosophy rest upon the guiiding principle that the goal of setup is to retrive recorded signal as accurately as possible on a distoriton analyzer. It does not rest upon visual satisfaction or a pre-commitment to visual method as the final benchmark. This is because visual satisfaciton bears no correlation to actual distortion levels on a distortion analyzer.
AnalogMagik allows users to determine optimal azimuth angle by measuring the crosstalk between Left and Right channel. Optimal position is achieved when the two numbers are as close together as possible.
Optimal Vertical Tracking Angle (or optimal SRA) is determined by measuring the Intermodulation Distortion level (IMD%), optimal VTA/SRA is achieved when both Left and Right channel displays the lowest level of IMD%.
Both Azimuth and VTA/SRA are determined by measurements, and not by visual satisfaction based on eyeballing.
The advantages of using 1 single
test track, not 3
The AnalogMagik Version 2 allows users to measure both L and R channel crosstalk, and VTA/SRA's Intermodulation Distoriton measurement in one go and using 1 single test track instead of 3.
When the test signals (1 khz test tone) for Crosstalk is separate for Left and Right Channel, they will be located on 2 different location on the record surface. One channel will have a higher tracking error than the other which will affect crosstalk readings albeit very slightly.
Having signals only on the Left or Right channel does not represent reality, because music LPs have very complex signals on both channels, not one. Using a combined L and R channel test signal, combined with VTA/SRA test signals, allows the stylus to experience a groove modulation much closer to a real live music LP.
In addition, setup parameters are not independent of each other, they are correlated and will affect one another. Having 3 test performed at once will allow users to account for the interaction between crosstalk and intermodulation distortion in real time. This greatly reduces setup time as well as increasing setup accuracy.
For these reasons, we actually observed a slightly different result between Version 1 and Version 2, and we believe Version 2's combined test track for Azimuth & VTA/SRA will result in a more accurate setup.
It is important to remember that AnalogMagik is just a distortion analyzer. It does not perform any adjustments, nor does it repair any inherent baseline distortion levels associated with your equipment. You have to make the adjustments to achieve good numbers. That is to say, AnalogMagik is best utilized when used as a tool to measure incremental changes. During the setup process, the ability to detect incremental changes is more important than the absolute number in itself.
For example, if your cartridge manual specifies a Channel Separation of 35 dB, but measured results falls under 30 dB, Analogmagik will not magically give out good numbers beyond the capability of the cartridge itself, nor will it do adjustments for you. It cannot force numbers to read what you want.
When setting azimuth, we observed that some cartridges are able to achieve number that is as close as 0.5 dB between Left and Right Channel. On others, you can sometimes get as close to within 1-2 dB difference between channels. AnalogMagik will not adjust the cartridge, it will not correct the channel separation specifications because that is a mechanical issue with the cartridge. That is the job of the cartridge manufacturer, not AnalogMagik.
It is also important to note that Channel Balance will affect crosstalk. If the cartridge or your phono stage has an inherent channel imbalance, it will render the Crosstalk measurement less accurate, resulting in a less accurate setup. Other cartridges have Zenith Angle Errors needs to be corrected, otherwise Intermodulation Distortion will be high.
There are several important factors which one may pay attention to when adjusting Azimuth:
1) One should never tilt the cartridge beyond 1 to 2 degree.
On a properly built cartridges, the cartridge should not have to be tilted beyond 1 to 1.5 degrees to achieve optimal crosstalk numbers. In most cases, the optimal number falls within 0.5 to 1 degree. If you find yourself having to tilt the cartridge more than 1 to 1.5 degrees to achieve optimal crosstalk, it is very likely that (1) other parameters are set incorrectly because all parameters are inter-related (wrong Anti-skating, wrong VTA Angle, wrong alignment), or (2) The cartridge has inherent imbalances, which is a mechanical issue of built quality. In such cases, it is an equipment limitation, AnalogMagik cannot fix this for you. It is a mechanical problem with manufacturing.
If your crosstalk analysis leads you to have to tilt the cartridge by more than 1-2 degree, the cartridge is tilted too much and will likely throw off the other parameters. Over time, it will also cause suspension problems due to weight imbalance.
2) Landing Behavior
Azimuth is highly affected by "Landing Behavior" which we talked about in the Basic Alignment Tutorial. If your cartridge has uneven pressure exerted by a cantilever landing behavior which is not going straight up and down, chances are you will never achieve a satisfactory Azimuth Crosstalk reading.
3) Azimuth cannot be set independent of VTA and Antiskating.
Due to the offset angle of headshells, as soon as you change VTA, geometry dictates that it will cause the horizontal level to change, ie) As soon as you change VTA, Azimuth needs to be reset.
Azimuth is also highly affected by Anti-skating and VTF (Vertical Tracking Force). If Antiskating is set incorrectly resulting in uneven pressure on the groove walls, this will often (but not always) cause an imbalance to the Crosstalk numbers. Therefore, you should try to optimize Anti-skating in order to achieve an optimal Azimuth setting. Changing VTF and VTA may also affect Crosstalk to you may have to go back and forth between different parameters and find an optimal point which results in a good set of numbers between all parameters.
4) Incorrect Zenith Angle on Cartridges, or incorrect coil angle at the end of the cantilever.
Zenith angle refers to the angle in which the diamond is glued onto the cantilever. Sometimes it is not perfectly straight, it actually happens quite frequently. Or the coil at the end of the cartridge may not be mounted perpendicular to the stylus. Please refer to the Zenith Angle Error section of the website for more information.