RIAA Equalization (was Re: AP-1615 Pre-amp)

[Alan 'A.J.' Franzman]

---- Original Message ----
> Date:    Sun, 20 Mar 2005 14:19:35 -0800
> From:    Fred Wittman <wittfa19 at EARTHLINK.NET>
> Subject: Re: AP-1615 Pre-amp
>
<snip>
> Also, there is the RIAA equalization.  If you are too young to
> remember what that is (count your blessings if that is so), there was a
> trick in recording on vinyl that boosted frequencies above 5KHz or 10KHz or
> so during the recording stage and re-attenuated them when played back. It
> turns out the ambient surface noise of the record was in that range and the
> equalization trick quieted it down.  (Try listening to an old crank-up phono
> and you'll know what I mean as soon as the record starts.)

Every wind-up gramophone I can remember seeing plays 78RPM records, and is
much noiser than a more modern turntable for several reasons, one of the
*least* of which is lack of RIAA equalization: 45 and 33 RPM records are made
of vinyl, vs. 78RPM which are usually shellac, filled with clay to increase
durability (to withstand those heavy tonearms or horns). It is the abrasive
clay filler which produces most of the continuous scratching sound heard on
78RPM records. The higher playing speed exacerbates this built-in noise, as
well as any additional noise due to contamination, scratches or other defects.

BTW, I'm almost too young to "remember" about RIAA equalization (having been
born in late 1968, and filled out my Beatles LP collection with the last
Capitol vinyl releases before CDs took over), but having a strong affinity for
things obsolete led me to learn about it anyway!

-- 
--------------------

Alan "A.J." Franzman

Email: a.j.franzman [ A T ]  verizon [ D O T ] net

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