[sdiy] OT: NAB vs. RIAA?

[Magnus Danielson]

From: Gene Stopp <gene at ixiacom.com>
Subject: [sdiy] OT: NAB vs. RIAA?
Date: Wed, 16 Apr 2003 16:59:56 -0700

> This is a great paragraph:
> 
> >It is precisely because there can be no perfect solution, that the design
> of
> >electronic music instruments will remain fascinating forever. The variety
> >will be endless, the debate over who prefers what and why will go on
> >forever, everybody will be right and wrong at the same time, and all
> parties
> >will be enriched by the disagreement.
> 
> Funny limerick - but I think that would make George Carlin blush! It's a
> keeper :)
> 
> Hey while I gotcha all - can anybody give an off-the-cuff description of the
> difference between NAB and RIAA preamp responses? Or to be more precise, if
> I wanted to run some tape heads directly in to one of those old Radio Shack
> phono preamp modules, what would the result be? Fine, close enough, bad,
> total crap? I'm googling now, but have not had any good hits yet.

OK. This is a job for the good old trustworthy Audio Engineering Handbook
(it's good - get it!).

In the tape corner there is two equalization schemes:
NAB - 3180 us and 50 us (50 Hz and 3150 Hz)
CCIR - oo us and 35 us

In the disc corner there is the o'l RIAA curve:
3180 us, 318 us and 75 us

Now, just by quicky goggling at the charts is that you probably would have an
excessively strong top. Since it is an old Radio Shack all bets are off anyway
;O)

It should not be a difficult task to wire up a NAB preamp for a guy like you
anyway. It's not magic, a quick Bode-plot design and you are home free.

Cheers,
Magnus