Wanted HiFi Choice Turntables & Tonearms - mid 80's

[Oldpinkman]

Does anyone have a collection of old HiFi Choice Turntable & Tonearms from the 80's. I am looking for the Martin Colloms analogy in the introduction to one of them (probably about the time the Pink Triangle Export was the current model) about the physics of gramophone record music reproduction. It was a scale analogy - the pivot for the tonearm was 4 miles from the stylus.

If you have a copy and can scan that section, I am trying to explain to Mrs S why an arm or turntable affects the sound, and why Arthurs new arms make the sort of differences they do (and why my new gramophone needle from Arizona hopefully will)

Not that I'm really sure any more - there are some wierd things to explain, but I think I'll start another thread for that

[phonomac]

Hello Richard,
I have an HFC with the introductory article you ask about - all text though, no diagrams. Is this what you are looking for?

If so PM me your email and give me a couple of days to get the scanner fired up and I'll send it over.

regards

Angus

[Oldpinkman]

Angus

Brilliant - thats the one. Will PM you

Thanks

Richard

[Oldpinkman]

Might make an interesting post - or addition to "the knowledge". i think many fail to appreciate what a bloody miracle it is we get any sound off an LP at all - before you start fiddling about with wiring and stuff.

Anyway - it'll help getting the idea across to Mrs S

[Oldpinkman]

Many many thanks to Angus for supplying the article. I remember now why both Arthur and I burned ours - it was the start of the dreaded "dynamic wow" bollocks. However, the bit I wanted is helpful, and Mrs S now has a bit of a better idea about why things like arms, mats and turntables make such a huge difference to how music from a record player sounds. (I wonder just how much even this simplified analogy is really understood by her - she's got a number phobia, and still regularly asks me questions like is 5 out of a 100 5%?)

I thought I should share the love - and help enlighten a few more why there is more to it than changing the wires in the arm. But we'll start with a quiz. I'd offer a prize, but I'm too tight and have nothing to give away - even that Linn basik cartridge has sentimental value. Anyway it would only encourage the most despicable cheating - and you should follow the Olympian spirit and compete for the sheer honour and glory. If you KNOW the answer, either because like Adam, you have the article, or because you are an engineer and good at sums, please don't spoil it for the rest. Post "I know it" and PM me for confirmation and public acknowledgement. A cartridge is an electrical generator. The stylus on a cantilever moves relative to a fixed cartridge body. It either moves the coils of the generator relative to the fixed magnet (moving coil) or moves the magnet of the generator relative to fixed coils (moving magnet). I don't need any smart-arse bringing up Decca London, or piezzo crystal cartridges for the sake of this quiz!! The key is the stylus needs to move relative to a fixed cartridge. If they both move by the same amount in the same direction, there is no output. If energy is moving the cartridge body relative to its supposedly fixed position (or moving the stylus other than as intended by the groove) you get a false signal. So, converting the Colloms scale to metric (The scale works for distance size only and not mass)

The tonearm is pivoted nearly 6 and a half kilometers from the stylus tip. The arm is 400m above the record surface, and the cantilever is 85m long. A 50Hz (mains hum) organ pedal note played loud requires a left to right (peak to peak) lateral movement of the stylus in the groove of 3200mm (That's a yard and a bit Gordon). (This is near, but not at the top of the movements a note would make the stylus move)

1) what is the lateral movement for a 10Khz violin harmonic at 50db less (not by any means the smallest note a gramophone needs to reproduce - but near that end) ?
2) How much is the vinyl groove itself squashed by the mass of the cartridge? (so - how much is it really squashed by the real mass - scale up the dimensions)?

Maybe I could persuade Marco to confer the title of "Official AOS clever clogs" on the winner by way of prize

[Oldpinkman]

Please post your answers on the new thread "Hifi quiz"

[The Grand Wazoo]

Please post your answers on the new thread "Hifi quiz"

...which you can find here