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October 2012 Issue
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ANGLE ISSUE

As Allen Edelstein says (Letters, August 2012), changing the vertical tracking force (VTF) of a pickup also changes its vertical tracking angle (VTA), so this could be responsible for changes in sound quality. He should note that if the pickup arm has an underslung counterweight, the converse is also true: raising or lowering the arm to adjust VTA will also change the VTF. Therefore either VTA or VTF could be responsible for changes in sound quality. Mr Edelstein believes that it is VTA, not VTF, which is important – but where is his evidence? The fact that his theory was published in Stereophile 30 years ago does not mean it is true.

Some basic information:

* record cutter VTA: 22 degrees

* Ortofon 2M VTA: 22-23 degrees;

* Goldring 2400 VTA: 32 degrees;

* Baerwald alignment lateral tracking angle error with 229mm arm: +1.9/-1.1 degrees.

 

The VTA changes caused by small changes in VTF or arm height are simple to calculate:

* 0.1g VTF change: VTA change 0.19 degrees (cartridge with 20mm/N compliance and 6mm cantilever);

* 1mm arm height change: VTA change 0.25 degrees (229mm arm).

 

If up to 2 degrees error in lateral tracking angle (which is more important than VTA, as it affects centre images) is acceptable and if cartridges may have inherent VTA errors of up to 10 degrees, how can a 0.2 degree VTA change have a significant effect on sound quality? 

If tonal balance is affected by changing tracking weight (which it is), the reasons must lie elsewhere - e.g. changes in generator alignment and compression of the rubber in the cantilever suspension. 

If Mr Edelstein wishes to continue to argue that VTA, not VTF, is responsible, he needs to come up with a scientific explanation for what he thinks is happening. When raising or lowering his arm pivot height to adjust VTA, he should also take care to rebalance the arm and reset the VTF. He may well find that when this is done the changes sound quality disappear, showing that they were caused by the change in VTF, not VTA.

Yours sincerely,

Alasdair Beal

 

Er - yes, Alasdair. As you note when changes in VTA are calculated they are minuscule. However, there are so many variables in this mix that I tend not to try and get too scientifically reductionist about it. The LP was a very ad-hoc analogue storage mechanism that sort-of got beaten into shape after it was invented – a strange way of doing things by modern standards, if one still in action today with the motor car. Vinyl LPs suffer an effect Benjamin Bauer of CBS Labs termed “lacquer springback” after cutting and this also makes actual mod slant angle of the groove approximate. Metal masters helped control this, but introduced other problems. It does seem that if a cartridge measures well it sounds half decent, but test discs are variable in themselves, making absolute accuracy is elusive. The LP is a gloriously approximate piece of plastic that I like to enjoy rather than get too serious about.NK

 

DE-MAGNETISE

Should I de-magnatize my 20 year old Clearaudio Signature Cartridge? If ‘yes’, then how should it be done? There is much conflicting advice on this subject and any help would be very welcome.

Stan Abrahams,

Ditchling, 

Sussex

 

Clearaudio say -

We do not recommend demagnetising our moving coil cartridges. Demagnetising a moving coil cartridge changes the magnetic field inside the cartridge which in some cases may be an improvement but not in others.  If you wish to experiment then by no means use any type of device that sends any current through the coils as this may destroy the very delicate 24 carat gold coils and permanently damage the cartridge.

Robert Suchy: President, Clearaudio

 

CLEAN SWEEP

When cleaning records with Knosti’s Disco Antistat, I’ve found a few fairly cheap extra items can help. First of all I clean the records using a carbon fibre brush. This gets rid of a lot of dirt on used records. Anything more stubborn at this stage I wipe with isopropanol on a cotton wool bud.

A litre of fluid is fine for two Antistat baths. Rather than mix used fluid with new I use old fluid bottles or something collapsible/airtight like a cycling water bottle for the used. (See figure 1). This I label.

The supplied filter papers leave something to be desired so I use coffee filters, which are much more effective at filtering record dirt. These are held in a stainless steel sieve (99p for a set of three). Normally I use the four cup size in a larger sieve, placed over a 2L plastic jug (99p for set of two.) Figure 1 shows the 2-cup filter. This not only provides a better filtering system, but makes it a lot easier to empty the Antistat bath without spillage. In this way the fluid stays clean enough to be used up to ten times, though by then I’d say it has lost its antistat properties and becomes more or a cleaning fluid. Still useful for improving not too important purchases though. Filters, sieves and jug are kept for the purpose.

While the records are drying I repair covers using a glue-stick or even sticky tape. When dry the clean records go into new sleeves.

One record I cleaned today was a 10-inch one of Songs by Tom Lehrer. Inside the cover I found a concert programme (Figure 2) for his show at the Royal Festival Hall on 29 June 1960. It’s a small booklet which cost one shilling and contains adverts, including one for a record of the show by him, in ‘super satirical stereo’ from Decca. Quite a bonus and something to treasure.

best wishes,

Melvyn Dover

Weymouth

Dorset

 

These items help keep LPs clean, says Melvyn Dover.

 

 

 

... and here is what fell out of an old LP sleeve. 

 

TRAD GARRARD 

Bubinga plinth, all internal spaces fully damped. Check out the brass inlay logo across the front... Its at Innovation Audio in Surrey, British Columbia, Canada. Excellent vintage retailer with fab repair/restore facility. Proprietor is one Gord Stauck. A rare resource in this part of the world. 

Andy Smith

Canada

 

 

"Old school" audio on the shelves of Innovative Hi-Fi in British Columbia,

Canada. Looks better than new school, doesn't it?

 

Like the picture Andy - thanks. Innovative Audio (www.iavscanada.com) has some tasty items on its shelves. I was bemused by Sonos labelling this as “old school hi-fi” (see p60) in contrast to their wi-fi connected all-in-one systems. How perceptions change. Whilst we are on promotion of specialist hi-fi services on the American sub-continent, Woodsong Audio, Sandpoint, Idaho USA (www.woodsongaudio.com) also make some lovely looking turntable plinths in a wide range of woods. I’ll stay with old school! NK



 

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