Speed of groove.

Speaking as an SME owner, their power supply is supposed to lock on to speed, 33 1/3, 45 or 78 and hold that steady regardless as to cartridge drag. Whether that happens or not, I've never bothered testing. But any power supply that is set up to lock onto a given speed should be able to account for the effect of the stylus in the groove. Or so I would hope.

Interesting question. Since the variation of tangential velocity that occurs across the record is presumably the same when the record is played back as when it is cut, and since one period of a given signal frequency will extend over a physically longer distance if it is located towards the outer edge of the record than if it is located towards the inner edge, I believe that it all cancels out. Signal frequency will be reproduced identically at the two locations, because the time required to traverse the distance corresponding to one period will be the same in the two cases. Signal amplitude at any instant of time, which is proportional to groove velocity at that instant, will also be maintained for the two locations, because as tangential velocity decreases towards the inner part of the record, a given groove excursion will occur over a correspondingly shorter distance, and therefore in the same amount of time, and therefore with the same velocity.

Regards,
-- Al

I think what you are saying is the velocity decreases as the stylus moves towards the inner groves of the record. If I'm not mistaken, output is specified by cartridge builder at a specific velocity; however, I don't know where that location may be on a 33-1/3 RPM LP record.

At some point of time on this post I saw response from Al (Almarg) but it dissapeared.
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