How many tonearms?

turning japanese
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hi_torq
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How many tonearms?

Post by hi_torq » 14 Dec 2018 15:27

Just thinking about Technics’ claim (e.g. of the SP-15) that 250 concurrent tonearms placed thereon, each tracking at 2g downforce, would not cause speed deviation.

What cack!

Conveniently, they do not divulge:

1. The radius. This of course is of paramount significance
2. The frequency, and recorded velocity of the groove modulation (assuming sinusoidal tone, of course)
3. The compliance of said cartridge(s) tracking at 2g
4. The stylus shape and tip radius

Discuss!

Alec124c41
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Re: How many tonearms?

Post by Alec124c41 » 14 Dec 2018 19:37

No discussion needed.
You can use any tonearm, mounted at the proper distance, with VTAs from 0.75 to 5 grams, with no problems.
You can even use a carbon fiber brush on the record with very little deviation from speed.
Technics made good DDs.

Cheers,
Alec

hi_torq
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Re: How many tonearms?

Post by hi_torq » 14 Dec 2018 20:29

Hi Alex,

I think you missed the point of my post. Indeed I have an SP-10Mk2 - and the ample torque of these units is not in dispute.

(And know I'm being contentious for the sake of it!)

My point was that they did not have to resort to pseudoscience in their advertising literature. Such a claim was unfounded without mentioning the test conditions, which could then be extrapolated to the theoretical 250 arms.

To clarify my position: What is the friction coefficient of an unmodulated groove vs. modulated at some known velocity and frequency? (Note that downforce is not in my list. I believe this to be irrelevant, so long as the cantilever grommet is operating within its elastic window.)

And yes, weaker TTs definitely do wow down when - say - an orchestral crescendo is reached.

hi_torq
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Re: How many tonearms?

Post by hi_torq » 14 Dec 2018 23:55

Alec - sorry! (Luckily the X is next to the C on the keyboard, so I can blame my sausage fingers! ;))

Alec124c41
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Re: How many tonearms?

Post by Alec124c41 » 15 Dec 2018 03:24

I have fingers, too, and usually have to make a few corrections to every post, here or elsewhere. I hated typewriters!
As for the point of the thread, advertising copy-writers often get off on the wrong tangent, thinking they are being smart.
BTW, I have an original SP-10, not an SP-15.

Cheers,
Alec

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