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PostPosted: 23 Aug 2011, 15:19 

Joined: 15 Mar 2010, 08:32
Posts: 487
Location: Canada
I just browsed over an old paper from the 1942 meeting of the Acoustical Society of America about the benefits of using an over-sized stylus to track a vinyl record.

Modern LP gets the groove wide of 1mil (1/1000 inch) vs old 78RPM 3mil wide.
So modern cartridges of small size styls when tracking wide grooves on old records will drop deep into the bottom of the groove & get pick up noise amixed with the music signals. No good.

So picking stylus of right size to track above or below the mean wearing track of groove wall is imperial.

What amazed me is the 1942 paper stated:-
"novel & unexpected benefits are obtained by use of a stylus of sufficiently large tip radius to contact only the upper portions of the side wall of a laterally cut phonogtaph record groove.

The benefits are:- (1) an increase in HF output; (2) a decrease in acoustic radiation from the surface of the record; (3) an increase in record life; (4) an increase in stylus life; (5) a decrease in picked up scratch from both new & worn records; (6) a decrease in stylus point pressure required for proper tracking.

The paper further stated a stylus of 4.2 mil radius vs its normal 2.3 mil would give such above performance. :o

No wonder my MM cartridge with a conical stylus tracks so well those old old recyled records. :P


"If the facts don't fit the theory, change the facts" quoted Albert Einstein.

PostPosted: 24 Aug 2011, 05:59 
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Joined: 08 Aug 2009, 03:11
Posts: 2229
Location: Chilliwack, BC
IIRC, the tradeoff was channel separation?

I don't think this has come up in recent memory. Should prove an interesting topic.


-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
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