[78-L] Approximating 78s age by physical characteristics

[Mark Bardenwerper]

On 3/3/2013 5:28 PM, David London wrote:
> On 03/03/13 23:10, Mark Bardenwerper wrote:
>> I can't add much to this, but it should be noted that many of the
>> groove additions came with the invention of automatic changers. The
>> change in labels had to do with the manufacturing process. The
>> beginning of the electrical era had something to do with some of these
>> changes. Before electrical recording, there were electrically driven
>> platters. Someone more in the know might tell us if there was a
>> workable changer in the acoustic era. It would have been a challenge
>> due to the heftiness of the arm, but people could be pretty imaginative.
> I was wondering also, if changers existed before lead-in grooves. It
> seems a key addition to a record, else you risk the needle just sitting
> floating on the leading edge of the record (or did they bias the arm to
> always swing inward when there was no groove?).
>
There was a lead in groove, which then took the needle to be captured by 
a concentric or elliptical groove. The changers worked best with 
elliptical because the adjustment for kicking in the arm lift was less 
fussy (that was adjusted normally by setting the starting point on the 
outer rim).

-- 
Mark L. Bardenwerper, Sr.

Technology...thoughtfully, responsibly.

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