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Interplay between VTF and anti-skate

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Interplay between VTF and anti-skate

Postby Bogester » 14 Oct 2017 19:19

From time to time I get the urge to tweak my setup to try and get the best out of it without forking out more money. My Rega RP6/Nagaoka MP-200 sounds pretty sweet as it is, but I want squeeze every last drop of performance out it. One area of adjustment that has always confused me is the interplay between VTF and anti-skate and, specifically, the fact that adjusting both can affect the tonal quality slightly. With my setup I have the MP-200 tracking at just under 1.9g, with the anti-skate a hair under that at around 1.8g. If I reduce the anti-skate by a small amount to ~1.7g, the bass quantity reduces slightly and the overall sound seems a little lighter and brighter. But at the same time, the dynamics and "punch" seem reduced (to my ears, at least). So, do my observations suggest that the anti-skate is set closer to correct at the higher value (which is itself closer to the VTF)? To complicate matters, the tonal changes brought about by changing the anti-skate can also be achieved by small changes in VTF. So I'm left wondering how to do the final bit of adjusting of the VTF and the anti-skate to ensure that I'm close to optimum.

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Re: Interplay between VTF and anti-skate

Postby analogaudio » 14 Oct 2017 20:09

If the tonal balance changes when VTF and antiskate are adjusted there is something wrong. The cart is designed to work over a range of VTF, and give the same tonal balance at all settings within that range.

Anti-skate removes the imbalance in the behavior of left and right channels in the presence of very loud music peaks when mis-tracking may occur causing gross distortion. It has no effect on the tonal balance, nor on the behavior of the cart at normal music levels.
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Re: Interplay between VTF and anti-skate

Postby Bogester » 14 Oct 2017 20:41

analogaudio wrote:If the tonal balance changes when VTF and antiskate are adjusted there is something wrong. The cart is designed to work over a range of VTF, and give the same tonal balance at all settings within that range.

Anti-skate removes the imbalance in the behavior of left and right channels in the presence of very loud music peaks when mis-tracking may occur causing gross distortion. It has no effect on the tonal balance, nor on the behavior of the cart at normal music levels.


Thanks for your input. I really don't believe anything is wrong. Perhaps "tonal balance" is overstating it, but the change in sound due to small anti-skate changes is easily discernible and more so with VTF. From all that I've read, it's well known that changes in VTF will alter the tonal balance to the extent that increasing VTF if it's too light can increase the bass and fill out the mid-range while going too high with VTF can attenuate the high frequencies.

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Re: Interplay between VTF and anti-skate

Postby analogaudio » 15 Oct 2017 20:00

There has to be a correct tonal balance, to meet the concept of neutral sound balance. Ask yourself how Nagaoka can quantify the sound of their cart if the sound changes when the VTF is changed from 1.5 to 2 grams? Which is correct? 1.5 or 2?

This puzzle has no answer because the truth is the sound doesn't change over the recommended VTF range.

You can't believe everything you read.
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Re: Interplay between VTF and anti-skate

Postby Doug G. » 17 Oct 2017 04:40

Well, small changes in the position of the cantilever magnet within the magnetic field of the cartridge will theoretically change voltage outputs of the channels, thus affecting the sound field. Adjusting both the VTF and anti-skate can vary the cantilever position.

As long as the stylus stays in contact with both groove walls, just set the adjustment to where you think it sounds the best.

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Re: Interplay between VTF and anti-skate

Postby Bogester » 17 Oct 2017 05:25

Doug G. wrote:Well, small changes in the position of the cantilever magnet within the magnetic field of the cartridge will theoretically change voltage outputs of the channels, thus affecting the sound field. Adjusting both the VTF and anti-skate can vary the cantilever position.

As long as the stylus stays in contact with both groove walls, just set the adjustment to where you think it sounds the best.

Doug


Thanks, this is my take on it. Also, since VTF affects VTA/SRA (more or less, depending on the compliance of the cartridge), changing the VTF is going to alter the sound. This idea that just because a cartridge manufacturer specifies a VTF range for a cartridge, does not at all mean that the cartridge will sound the same (tonally or in some other respect) throughout that range. The thing with analogue is that practically every change can have a discernible effect on the sound. What I can say from personal experience of quite a number of cartridges on several turntables is that changing the VTF within the range specified by the manufacturer definitely changes the sound in a way that I would describe as "tonal balance". I do agree that there's a lot of misinformation out there about turntable setup and I take much of what I read with a pinch of salt, but I've read a number of quite in-depth articles that at least look authoritative (well, they convinced me they know what they're talking about :-) ) and they describe changes in bass/treble, soundstaging, and so on that result from VTF changes, so I'm pretty sure it's not my imagination or some basic setup issue (I'm darn sure my cartridge is well aligned, for example). As regards anti-skate, I'm coming to the conclusion that relatively few people have got this set absolutely correctly (if there is such a thing), and most either follow the tonearm manufacturer's advice (which is usually set it the same as the VTF) or do as you've suggested and set it to what sounds best. As my original post mentioned, in my hands the latter approach has left me befuddled because small changes to VTF and anti-skate can alter the sound in similar (though not exactly the same) ways. I've seen articles about using the "relative dynamics" method for setting anti-skate (comparing the dynamics of the left and right channels), such as this one: http://www.hifiportal.co.uk/Articles/Ar ... 0Guide.pdf


While this didn't work for me exactly as described, I could certainly hear that changing the anti-skate affected the overall dynamics of the sound - too low and it sounded a little vague and unfocussed, too high and it sounds a bit lifeless and "heavy". So I've come to conclusion that I can't be far away with my current AS setting of a little under the VTF value.

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Re: Interplay between VTF and anti-skate

Postby H. callahan » 17 Oct 2017 06:45

Well, yes the anti-skate.

You probably know why the antiskate-device was invented. Friction between stylus and groove, skating-force due to offset tonearms and/or cartridges, a stylus which gets pushed onto one groove wall due to skating-force.
Now if the stylus is pushed towards one groovewall due to skating-force, it just can´t track the modulations as precise as if it wasn´t pushed by the skating force towards one groove wall.
If the antiskating-device now is applied correct the stylus should be pressed equally onto both groovewalls.

Therefore its logical that the reproduced sound does change if the antiskating-force is altered - but the questions is whether that´s audible or not, as this depends on pretty much everything: Record quality and condition, music genre, tt, cartridge, tonearm, stylus and stylus-shape - but in theory it should change the soundreproduction.

Now if you can hear a change its great because then you can fine-tune your setting by ear. Because the skating-force originates of friction between stylus and groove, VTF and anti-skate are related to each other. If VTF is increased friction between stylus and groove also is increased, therefore skating-force increases and anti-skate has to be increased to compensate.
As the ideal situation would be no skating-force at all, lower VTF would be preferrable as skating-force is lower when VTF also is lower. Of course one can´t lower VTF endless as sooner or later mistracking does occur, but the lowest possible VTF still giving good tracking should be best.
Therefore it can be hard to find the best settings, as skating-force changes with VTF, but you might want to try some settings like:
If the manufacturer recommends VTF between 1.5-2.0, you can try VTF of 1.5, 1.75 and 2.0 and play with anti-skate until it sounds best to your ears - then you pick the VTF it sounded best, let´s say 1.75. Then you might want to try 1.7 and 1.8 to see whether 1.75 is the best setting or if it´s juuuuuuuuuuust a bit off the ideal setting... depending on how many last drops you want to squeeze out.
.....................

Whether its a rule of thumb to set AS a little under VTF is doubtful, as there just might be a small inaccuracy in the scale of the VTF- or/and AS-setting - but that doesn´t matter as long as you can hear the optimum setting, which fortunately is the case.
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