XV-1S and Antiskate

On a grooveless record the POINT of the stylus rides on a flat, unmodulated surface. The contact surfaces don't touch anything.

When you listen to music the SIDES of the stylus ride on a pair of opposed, modulated walls. The point never touches anything.

These are two quite different conditions. Extrapolating from one to the other is fraught with untested assumptions. By analogy, you tested Z-rated tires on a warm, dry track, found them to perform well at a certain psi, then extrapolated that psi to winter tires for driving in snow or off-road tires for driving in mud or sand. Experienced drivers know better.

Skating forces do exist. They can be approximately compensated for with anti-skating. I say "approximately" because on real records the amount of skating force is ever-changing. The question becomes, how much (if any) anti-skating to use for real records? There's no simple or perfect answer and there are several factors to consider. Here are some:

1. Anti-skating may extend the life of a stylus. OTOH, cartridges with modern stylus profiles like the XV-1S tend to wear out their suspensions before their styli. When you have that rebuilt you'll get a new cantilever-stylus anyway. (Actually, the XV-1S tends to have its full monty cantilever snapped off before ANYTHING wears out. Of course playing with an unprotected stick is another issue.)

2. Anti-skating stresses a suspension, so one could argue that it further shortens the most short-lived part of the cartridge. Hah!

3. Anti-skating impairs sonics. You said the sound doesn't change that much, but then rather vaguely said anti-skating makes it "warmer". It changes the sound in my system and I hear very specific things. As with any form of dampening, pre-pressuring the cantilever against the suspension attenuates HF's, slows rise times and reduces amplitudes. This could be called "warmer", I call it dulled and lifeless. Like Audiofeil, I've heard this with the XV-1S and other top level cartridges, including several of my own.

4. My amp and preamp builder, Nick Doshi, states as one of his core design principles, "allow as few gain blocks as possible". If you've never heard one of his units you may not appreciate the significance, but I do. Anti-skating is a gain block. It inhibits cantilever movement in exactly the same way that excessive VTF does.

There's no right or wrong (other than using grooveless records to adjust parameters for playing grooved ones) but FWIW I bought my system to play music and choose to adjust it for optimal sonics. If this slightly reduces some component's lifetime, oh well. An occasional Shiraz or single malt may effect my component lifetime too, that's a tradeoff I'm willing to make. Of course there are risks I won't take, regardless of the excitement, but we'd have to discuss those on another forum. ;-)

Doug

P.S. While experimenting with lower and lower amounts of anti-skating I actually went through a period of tweaking it for each LP. The differences in tracking performance and sonics from very tiny changes were quite audible. I now use none because my main cartridge no longer needs it to track even the toughest passages.

P.P.S. As I no longer use anti-skating, I removed the device from my (TriPlanar) tonearm altogether. This had a small but beneficial effect in lowering the arm's noise floor. The fewer twiddly bits to vibrate and put noise into an arm, the better.

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.

Lew,

With some (many?) cartridges you may never get away with zero A/S. IME it's quite cartridge-specific. We've heard variations between multiple samples of the same model. Paul believes this is due to sample variability in the behavior of elastomers. Each cartridge must be tuned individually for optimal behavior (sonics).

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Jonathon,
Thanks as always for a truly informative post.

To be clear, my description of "slower rise times" and "attenuated amplitudes" wasn't a deduction from principles. It's what we actually hear. Of course I'm open to explanations other than cantilever damping, but they'd have to account for these observed phenomena.

While it's true that the cantilever is pre-loaded against the suspension by the cartridge manufacturer, when the user increases the amount of pre-loading he alters the behavior of the system. This is true in any spring-loaded system.

Example: like most off-road vehicles, my Land Rover has a long travel suspension. When driving by myself, my massive 140 lbs. don't add much to the 4,000 lbs that the manufacturer pre-loaded on the springs. Result? The vehicle rides high on the springs, over certain bumps it's a bit jouncy ("lively" or even "edgy" in audiophile terms). Now add three 200 pound passengers and a pile of gear. What happens? The springs are compressed toward the middle of their range, the vehicle's rise times are slowed, it's amplitudes reduced (it rides "warmer", in the OP's parlance).

Spring-loaded systems vary their behavior not just between pre-loaded or not pre-loaded, but also with the amount of pre-loading. Few elastomers respond linearly to compression.

I just can't think of a better explanation of why we hear "slower rise times" and "attenuated amplitudes"...

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Downunder,

When I first posted about removing my A/S device (on "TriPlanar Tips"), I remember joking about HW being right all along. :-)