Re: [ARSCLIST] Fw: [88sOn78s] Exit Grooves on Shellac and Early Vinyl

[Steven Smolian <smolians@xxxxxxxxx>]

The first need to trip a changer mechanism was for the Orthophonic changer,
c. 1927.  Previous to that, there were devices that stopped the turntable
when it got to the end of the side, triggered by either an excentric groove
or a device fitted over the center hole that performed the same task,
particularly for records without this groove.

The next device requiring the end-of-recording signal was the juke box, in
the early 1930s.  A similar mechanism was then available to the
record-buying public in changers.

I'm not aware of the development history of this feature outside the U.S.

Steve Smolian

----- Original Message -----
From: <Mwcpc6@xxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxx>
Sent: Friday, May 20, 2005 11:20 AM
Subject: Re: [ARSCLIST] Fw: [88sOn78s] Exit Grooves on Shellac and Early
Vinyl


> In a message dated 5/19/2005 5:51:27 PM Eastern Standard Time,
> smolians@xxxxxxxxx writes:
> Sending this to the ARSC list.
>
> Steve Smolian
> In a message dated 5/19/2005 2:12:20 PM Eastern Standard Time,
> jodythornton@xxxxxxxxx writes:
> My question is:  Why do electrically recorded shellac discs, and early
> vinyl LPs have an exit groove that zig-zags back and forth, when it
> spins?  Why did they go to a stationery exit groove in the early 60s?
> Can anyone accurately/technically answer this.
> ***********
>
> I have old record changers that use a ratchet and pall mechanism that is
> dragged along by the tone arm to trip the change cycle as soon as the
> motion of
> the arm is reversed. This allows the cycle to be started even if the
> eccentric
> groove is at a large diameter, as on some short selections I've seen.
>
> This is probably the simplest way to trip the changer, but it means there
> is
> a constant drag on the arm so it was abandoned when very low tracking
> force
> cartridges were developed. The "velocity trip" mechanism only requires a
> slight
> tough on the trip pall once per revolution so it disturbs the arm much
> less.
>
> Since most changers had a "fail safe" feature that would trip the cycle
> eventually even without a reversal of the arm and as the eccentric groove
> required
> a special mastering operation, it was eventually abandoned.
>
> It seems to me that there was an organization, the RMA (Record
> Manufacturer's
> Association) that coordinated these things but I am unable to find any
> reference to it through the search engines. Does anyone have any links to
> the this
> history on the Internet?
>
> Mike Csontos
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.322 / Virus Database: 266.11.12 - Release Date: 5/17/2005



--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.322 / Virus Database: 266.11.12 - Release Date: 5/17/2005