XV-1S and Antiskate

Musichead,

I heard an XV-1S cantilever snap from across the room once. The owner was aligning the cart and had one brief moment of inattention. Be careful, it can be done without really trying.

Agree with Lewm and Syntax that the decision of how much anti-skating to use, if any, must balance sonics vs. the desire to counteract this unavoidable force. Definitely a YMMV, there is no perfect or correct answer.

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As to Lewm's question about gain blocks, Nick didn't limit his principle to "active devices in the signal path" and I doubt he'd agree to. A poor quality capacitor or resistor will act as a gain block, though it's not active. A crappy power supply will act as a gain block, though it's technically not in the signal path. I wouldn't accept either of these proposed limitations.

Even if we did, I could argue that a cantilever is an active (or at least kinetic) device. It's powered by groove modulations rather than electricity, but if we somehow prevented it from moving there would be zero signal.

It's certainly in the signal path, that's clear. There's nothing else between groove modulations and generator and if we removed the cantilever there would be zero signal. It's not just in the signal path, it IS the signal path.

So, think about what happens INSIDE a cartridge when we apply an external lateral (or vertical) pressure to the tonearm: the cantilever (signal path) is artificially pressured against the elastomers in the suspension.

Press any vibrating rod into any elastomer and what happens to the vibrations?
1. Rise times are slowed, always.
2. Amplitudes are attenuated, always.
The exact effects will vary with frequency and with the materials involved, but this is as clear and direct an example of a gain block as I can imagine, and it's precisely what excessive anti-skating AND excessive VTF do.

FWIW and IME, some cartridges that eventually play well with no A/S do need a little when new. The suspension may need to relax before the cart can track tough passages without a touch of A/S.

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I wouldn't regard a Graham's damping fluid as a gain block. It's more like an out-of-signal-path resonance filter. Using too much does sound exactly as Syntax described on a 2.2.

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Excessive A/S can do what Syntax's scary photo showed. Low or zero A/S can never do that under any circumstances.

I found that the proper way to set anti-skate on my TT is by ear.

Start out way low on the anti skate, after you have the cartridge alignment and VTA and tracking force dialed in. This is the last step. Listen to the dynamics of a piece od music you know well, use something that has some continual dynamic, like an uptempo drum and cymbal, as well as voice; specially the right channel. Then slowly raise the anti-skate a bit at a time and reassess. Go slowly and only move a little bit at a time. You should hear the dynamics in the right channel come up slowly as the anti-skate increases, then eventually both channels will begin to improve. Keep going a wee bit at a time and you will hear the dynamics and quality fall off pretty suddenly. Back it up a bit until they come back and ... there you go.

It is very apparent that the sound quality changes as the anti-skate amount changes. There is an apparent "best" place, which could vary from one setup to another and not necissarily coincide with a manufacturer's recommendations.

Doug, Thanks for the explanation, but by that loose definition, what is NOT a gain block? Only straight wire, most likely. But then, wire also affects sound. In the parlance I am used to, the term "gain block" would be interchangeable with "gain stage" and nothing else. Anyway, as the late great Gilda Radner once said (as Emily Latella on SNL), "Never mind".

In my system, with both the Triplanar and a Dynavector DV505 tonearms and any of my many MC and MM cartridges, no AS results in a R channel bias and some low level distortions that are cured by a minimal amount of AS. I start with zero and add teeny amounts until the problem is cured. I have you and others to thank for the concept that a minimum amount is best, but I cannot get away with none, so far.

Doug:
In most MC cartridges, the coil former and coils are located at the rear end of the cantilever, and are always being pressed into the dampers. Since the amount of pressure affects things like tracking and frequency response, it is the cartridge builder who sets the net pressure (during the building and adjustment process), and the pressure adjustment is locked down by screws so that the value cannot be reduced (or increased) inadvertently. If it does become reduced, chances are that the cartridge will ride too close to the LP surface (low-rider).

Due to the constant pressure between coils and dampers, "slower rise times" and "attenuated amplitudes" simply describe how most MC cartridges work normally. These are not issues that suddenly appear because the user happens to choose antiskating or VTF values that are higher than optimal.

What excess antiskating can do is cause uneven loading of the stylus profile within the LP groove, angular misalignment of the coil former and imbalances in the forces that act on the same. The antiskating effects manifest themselves in the horizontal plane.

Doug, I agree with you that improper VTF is conceptually similar to improper anti-skating. What's different is that, unlike AS, we need a minimum level of VTF to ensure adequate physical tracking of the groove (but uneven stylus loading in the LP groove is no longer an issue). And since VTF forces are typically 5-10 time higher than AS, compared to AS we get a far greater degree of angular misalignment of the coil former and imbalances in the forces that act on the same. And, it is in the vertical plane that we see the effects.

As problems to be solved, AS is far more intractable than VTF. VTF requirements don't change across the LP, so it is possible to understand in advance what value works best and specify this (although changes in ambient temperature and humidity may require some readjustments). In contrast, AS requirements change according to the LP groove radius and groove drag (caused by groove modulation and stylus profile). It is possible to solve the groove radius issue, but the groove drag issue is more doubtful, unless you are using a linear tracking arm or some kind of electronic servo arm.

I suggest that it is much easier to speak of a "right" and "wrong" VTF setting than AS.

cheers, jonathan

Very interesting.

After living with a VPI HRX for quite a few years, antiskating was not really offered, except for the wire twist, which always sounded worse. VPI has always copped a lot of criticism for this approach with pundits/experts stating that no AS will cause cantilever alignment issues.

Now, some on this thread intimate that AS will cause cantilever alignment issues. I assume this is when it is higher than the VTF?

Does AS coninciding with the recommended VTF cause cantilever issues?

So has Harry Weisfeld been correct all along that the best AS is no AS ?

I must admit I use antiskate now,as my tonearms have it. I may play around with less than receommended level's now

cheers