VTF and Anti-skate essential tuning

Collector’s Corner: Audiophile Tune-Up

Have you checked your tonearm anti-skating settings recently? 

I hadn’t for probably five or six years, umm, or possibly longer. The system’s been sounding great, why look for problems? Because you don’t know if it can sound even better.  It can, if performance is being held back by sub-optimal alignment of the tonearm anti-skate setting.  If it is, you have a great upgrade at virtually no cost.

I’m not going to rip a test record. The testing requires the vinyl to be spinning on the turntable, while you sit in front of the speakers to assess the need for adjustments.

First off, the test LP gives you an unambiguous test, our German friends know their left from their right. Despite all the interconnects following the cabling colour scheme meticulously, the left and right channels were inverted. There is a bit of rogue wiring inside a box somewhere, easily put right by switching left and right interconnects (not opening up every box to correct it internally!)

The speaker phasing was perfect. A wrong wire there and you lose  stereo focus, so I didn’t expect to find a problem and there wasn’t. Ah but the skating! Way way off! 

As a record rotates, the stylus tip (left, electron microscope photo) navigates the groove, collecting the musical information stored in the shape of the groove walls. The left and right channels of a stereo recording are cut into the left and right groove walls. The diagram (right) shows how the single stylus tip moves to reconcile the left and right channel information.

Stylus tip movement is relayed by the cantilever to the cartridge, where it is translated into electronical signal by passing magnet fields.

As the record rotates, the tonearm is pulled gently towards the centre of the record. This causes the stylus to push harder on the inner side groove wall, and reduces contact with the outer side groove wall.  If the stylus tip is not riding dead centre in the groove, the left and right channel balance is compromised, the stereo image will be off centre and instruments placement out of focus, and distortion on the channel where the stylus has insufficient contact.  Tonearm anti-skate adjustment applies an opposite force, to pull the tonearm and stylus back into the correct position in the centre of the groove, and read both groove walls equally.

The stylus tip is enormously sensitive, reading changes in the undulating groove wall (aka music) as little as one thousandth of the thickness of human hair. When playing music, the listener is unlikely to pinpoint the problem of misaligned skate due to constantly changing audio dynamics. However a controlled single test tone, alternately only left channel, right channel and centre, quickly identifies maladjusted skate, as the centre tone image leans to one side, which mine did, massively. Huh, and I thought it sounded great! A quick adjustment to the tonearm anti-skate brought the tone back into the centre between the speakers.

Putting music back on the turntable, the stereo image was audibly more solid, with a room presence that you realise had been missing.

However one more adjustment is needed: VTF, the tracking weight, the vertical force down on the cartridge in the groove. That was optimised at around 1.8 grams about eight years ago.  We will give VTF a once over and recheck the anti-skate setting at a future listening session. And maybe the VTA, not forgetting the all-important WTF?

All the hype, remastering from original tapes, 180 gram vinyl, hi-fi equipment snobbery, all counts for little if your setup is not optimal, and all that requires is a hi-fi test record, and an understanding of why you need to use it. I am grateful to Man-in-a-Shed and Mr Speaker for educating me to speak High Fidelity.

Hi-Fi enhancement secrets : a bottle of rosé.

While group listening to hi-fi, we apply a generous quantity of rosé – Cotes de Provence is recommended, wine intended to be pink, not a bi-product of making red. Over the length of an afternoon, a few glasses of rosé can improve the listening experience remarkably. However, h-ifi tweakers should note, an excess can lead to arguments (cross-talk), impair the ability to walk a straight line (miss-tracking), or even succumb to the force of gravity (skipping out the groove altogether). So take care. Happy listening.