Anti-skating question

I recently installed a new phono cartridge (DynaVector 10x4 MkII on Origin Live modified Rega RB250 on Planar 3 table). At first, I set the anti-skating force so that on a spinning grooveless record surface the tonearm would pretty much stay where it was set down or drift slowly outward. That, I assumed, was a pretty good and direct way to set the level of anti-skating force needed. Then, I put on HiFiNews&RecordReview’s test LP and used the anti-skating tracks – basically, you adjust the anti-skating until you hear no tracking distortion of the test signal in either channel. This procedure gave me a very different setting – one that does not counter (not nearly totally, anyway) the inward skating of the tonearm when set on a grooveless record surface. I would have thought the two methods would have produced more similar results. Any explanation for this? (I’ve stuck with the sonically-based setting for now.)
Your choice to use the sonically-based setting is correct. A grooveless LP adjustment cannot take into consideration the velocity forces encountered by the stylus in the groove of a actual LP. To confuse this issue even more, the azimuth and tracking force of the cartridge will also alter the anti-skate setting. Even the thickness differences of your test LP and the grooveless LP could be part of the adjustment difference. You should try using real music, something you really love. If the setting you have arrived at from the HINews LP still sounds like the correct adjustment, great! If not, go with what produces the most accurate channel balance and imaging, combined with clear top end and bass on the music you are most familiar with.
You have to remember that the reason anti skating is necessary is from the effect of the grooves on the stylus. Using a grooveless record is not the same as a stylus in a groove. It is a good starting point, but once the stylus tracks in a groove, it requires more anti skate. This is my least favorite part of setting up a turntable. Unfortunately the tedious method of using the test record is the only way to go. Arms can't accurately be calibrated for anti skate, so don't ever trust any factory calibrated dial. Again, it would be a good starting point. Listening by ear has always seemed bad, because it is not good to play any record over and over again. They need to rest so that the deformed plastic can return to it's proper shape. Hope I have helped.
The correct use of anti-skating bias force is to counteract the force generated by the rotating (and modulated) groove interface with the stylus. A blank album side exhibits none of the characteristics of a real record. There are a number of reasons, some of which have already been stated, but using a blank record side will always leave you with much lower anti skating than would be necessary. The method of using distortion detection is a good approach, assuming that you have a test record with increasing modulation levels. Play the record up to the modulation level that causes audible distortion noting which channel is distorting. Increase (likely) the bias force and perform the test again, hopefully you will find that the distortion now occurs only at a higher modulation level. Continue the process until you reach a point where both channels distort at the same modulation level. Keep in mind that tracking force will greatly affect your levels of bias force. A good starting point is to use the highest tracking force recommended by the cartridge manufacturer. Do not fear going even slightly higher, cartridge (and LP) wear are typically caused by inadequate tracking force, this is due to the loss of contact between the stylus and the modulated groove. Kevin Halverson
Well stated, Kevin and Albert.
Good info here guys. Thanks for taking the time to post it. Any suggestions as to good discs that you could use when initially setting up a vinyl rig ? What do you consider "too high" of a tracking force in terms of record wear ? I think my current cartridge calls for appr. 1.75 to 2.0 grams, which used to worry me quite a bit. Sean >
Thanks very much for the replies, folks. My puzzlement is that I’ve had to set anti-skating to less than what I’d expected, not more. To illustrate: Tracking force is 1.9 grams, at the high end of manufacturer’s suggested range. Using the visual, grooveless record method, I set anti-skating to a certain level. When I put on the test record (has four tracks with signal stepped up in amplitude to gauge anti-skating), this setting results in the left channel starting to mistrack before right channel, and I have to reduce anti-skating to achieve balanced L-R tracking. This is the opposite of what I would have expected. ………. Well, this really is mostly just intellectual curiousity. With so many geometric factors at work, it’s a puzzle. The setup is checking out OK according to the test record (with possible exception of azimuth, which may need fine-tuning of such a small degree that it might drive me crazy to attempt on a Rega arm), and the setup is sounding fine and balanced when playing real music. I’ll just continue to listen as the cartridge breaks in. If anyone wants to comment further, I’ll read with interest.
Sean, the record I mentioned in my original post covers the setup bases. One source for the record is MusicDirect. As for vinyl wear, I wouldn't consider anything up to 2 g to be a problem at all if your stylus is in good shape and the arm is tracking well.
A bit off topic, but does anybody know of a website with turntable setup help/advice?
Arcmania, Laura Dearborn's article on turntable setup shows up several places on-line, including The TNT-Audio site has an article that describes the HFNRR test LP i mentioned earlier. It's a good record for those who don't have testing equipment. A post at Vinyl Asylum has some more links on the subject.
Hmm, lost some info in my previous attempt to post this..... Arcmania, Laura Dearborn's article on turntable setup shows up several places on-line, including ..... The TNT-Audio site has an article that describes the HFNRR test LP i mentioned earlier. It's a good record for those who don't have testing equipment. ..... A post at Vinyl Asylum has some more links on the subject.
Thanks Jayboard, those were very helpful
You are right to set anti-skating by using modulated groves rather than blank bands on a record. The inwards force arises because a tangent to the record grooves, at the point of contact of the stylus, makes an angle of about 20 degrees to the line from the stylus to the pivot. The friction between the record surface and the stylus exerts a force on the stylus in a direction which is tangential to the record, and this is opposed by the tone-arm which pulls in a direction from stylus tip to pivot; however since these two forces are not acting in opposite directions, there is a net inwards force which is given by the following equation. Inwards Force = F * sin(theta). The angle theta, between the line from the arm pivot to the stylus and a tangent to the record groove is easy to calculate, the friction is a different matter One might expect that the friction would be less when the stylus rests on a blank band, but your observations contradict that; I also noticed the same effect with my turntable; and there was a long experiment conducted by Helge Gunderson on the Vinyl Asylum about the same question. My guess is that the stylus is carefully polished so as to reduce the friction between it and a V shaped groove, and when the stylus rests on a blank band the friction is higher, as it is the tip of the stylus which determines the friction in that case. The key point here is that many people (including the article by Laura Dearborn) recommend setting anti-skating using the wrong method, ie so that the tone-arm moves slowly outwards when resting on a blank band. Experiment shows that when anti-skating is correct it usually moves inward. Brian
Interesting. My results were counter-intuitive (or at least counter to my expectations), and it's reassuring to know that others have gotten the same kind of results. Thanks for posting.
This question is for Jayboard: Can you tell me the results of the O.L upgrade. What did they do, I know they replace the tonearm internal wiring. Is this one run all the way to the rca's, did they replace the end of the arm with a weighted stainless end and the same upgraded counter weight? What was the cost? respond to [email protected] thanks JP
Hi, Joepetro. Not to put you off, but I don't think you can do better regarding what's involved with the upgrades than the OL site, Anyway, the numero uno upgrade is structural, not electrical. OL re-machines and replaces the counterweight and counterweight stub to reduce resonance in the arm. Upgrade of next importance is internal arm rewiring. After that the rest of the wiring. I bought direct from OL new RB250 arm for ~$130 with first and second upgrades at ~$88 and ~$82, respectively. You can probably do better buying in U.S. from Galen Carol Audio, and I think there's another American distributor now. BTW, OL has a pretty good selection of phono cartridges, and if the exchange rate is still good, buying overseas from them amounts to a very good deal. HTH.