Discuss The Viv Lab Rigid Arm

Mijostyn, please do a little more thinking before erupting. Zenith error has an equally destructive effect on alignments whether you’re using a UH tonearm or a conventional one. In both cases you lose null points and TAE is exacerbated. But, come to think of it now, with a UH situation, there might be a point on the arc of stylus travel where zenith error by chance corrects for TAE, and you’d actually have less TAE (maybe even a null) at that moment. I wonder whether Dave has looked at that.

On the day Dave "twisted" my cartridge (Audio Technica ART7) to correct for its zenith error, using an electronic method, not guesswork, my ears immediately picked up to the effect of the proper correction. And Dave’s did too. It was quite obvious that the SQ had ticked up a notch or two. So, with an overhung tonearm (in this case, Kenwood L07J tonearm on my L07D turntable) I certainly can hear TAE errors. Currently in the Viv I am listening to my ZYX Universe. That cartridge has never been re-tipped. By visual inspection using my Olympus microscope, it has considerable zenith error in the mounting of its stylus, in that you can easily see it by microscopy. Whereas the two other cartridges that have been in the Viv (Dynavector 17D3 and Ortofon MC7500) may also have zenith error, but I cannot see it by visual inspection.

@intactaudio 

I have a hard time believing that the distortion created by the underhung arm is euphonic. But, whatever. My approach is always to setup my system with a scientific approach. In order to determine what is going on with the Viv arm I would have to buy one and a second cartridge. It is far enough afield that I am not interested in doing that, the deeper dive. Knowing what phase errors do at high frequencies my supposition while not proven is as likely as any other. The distortion caused by zenith error is easily measured. As for cartridge set up. I prefer Lofgren B because it has the lowest TAE across the entire record accept at the last 2 cm which are usually not used in modern records and most older ones. Setting a cartridge up is a very fastidious process that requires the right tools and a sharp eye. If you have not used a SmarTractor I highly suggest you try one. It looks intimidating at first. After a few installs you'll never understand how you managed without it. The WallySkator is also very useful as is a proper USB microscope  and computer program. The WallyScope uses a great head unit from Amscope and a great program, but the stage is a work in progress. I know of no horizontal stage that is appropriate for a high powered microscope. I my case I made my own cannibalizing an old medical microscope.     

@lewm 

Zenith error and TAE are almost identical. The stylus is presented to the groove at the wrong horizontal angle. In the case of TAE the entire cartridge is at the wrong angle. One can safely assume that the distortion would be very similar between the two, perhaps a bit worse with TAE.   

You like the sound of the Viv arm and there is no way I can argue with that.                       

@mijostyn 

How do you know you actually have the alignment you say you do?  Here is a test report of three random samples of stylus assemblies from an order I placed.  This is representative of the best numbers I have seen thus far and are kind of terrifying.

I don't care how great of a protractor you have if you are aligning to a cantilever without consideration of possible diamond set error then I see the baby going out with the bathwater.  JR addresses this by optically placing a number on the Zenith error and then providing a protractor with the ability to correct for this error.  Next we can open the can of static vs. dynamic worms and observe how much skating forces and groove modulation come into play here as well.  In many setups, when you adjust azimuth to better crosstalk numbers you also change your alignment.  Add or remove a gram of anti-skate correction and you have just changed your alignment.  Its really easy to brag about a preferred alignment and the precision of your setup and quite humbling to realize you are actually nowhere near where you thought you were.

dave

Mijostyn, It does not behoove you to use the term "scientific" in this context to justify any of your thinking on the subject. Your approach fails the scientific method on first principles. You are operating within a belief system that starts out with TAE = bad. But I concede that neither of us has the actual data, apart from Intact Audio’s data, to justify any claims at all. I can say that when Dave "fixed" the zenith error on my ART7, it suddenly sounded better. He also measured the resulting TAE which reverted to the textbook look for a well aligned cartridge in an overhung tonearm. This certainly is consistent with the notion that TAE matters when zenith and the alignment according to accepted algorithms are both correct, for an overhung tonearm (with AS applied and azimuth set to 90 degrees, as well). Can you find a paper in the audio literature where the effects of TAE on the audio signal were looked at with a ’scope or some other valid method, that quantifies distortion of one kind or another? I cannot so far. This subject is only interesting if you approach it with an open mind. And I certainly don’t blame you if you don’t want to buy an underhung tonearm, but it does hamper your capacity to make a judgement on them as a class. Like I said, I took a flyer because the Viv has received near uniform positive reviews, because I could buy at a considerable discount in Japan, because I have also had good results with the weird RS Labs RS-A1, and because a major company (Yamaha) has seen fit to produce an expensive turntable with a built-in underhung tonearm. (I don’t use the RS-A1, because it is very finicky and most of all because it dangles the counterweight from the rear of the arm in order to place its center of gravity at the surface of the LP. This leaves the CW to sway like a pendulum, literally on off-center LPs, which cannot be good for the cartridge suspension. But the RS-A1 displays many of the positive good qualities of the Viv.)

I did find some papers on this subject.  Here is a long post from Vinyl Asylum.  The author makes the good point that TAE affects only frequencies encoded in the horizontal plane (low frequencies), and he states that the distortion due to TAE is Harmonic in type. That may explain why if there is distortion due to TAE with the Viv and similar underhung tonearms, I (at least) do not find it objectionable.  Also, the level of distortion is inversely proportional to velocity, meaning HD will be higher near to the inner grooves. The math is complex and will take some time for me to digest:

https://www.audioasylum.com/messages/vinyl/43557/tone-arm-geometry-and-tracking-distortion-longish

Finally, the post opens the door to think maybe the skating force is more obnoxious than TAE.