[sdiy] OT: RIAA curves of Standard Equalization

[Magnus Danielson]

From: "Nicholas L." <NLenczewski at rogers.com>
Subject: [sdiy] OT: RIAA curves of Standard Equalization
Date: Thu, 15 May 2003 22:06:22 -0400

>     Hi,

Hi,

>     While I may have been searching in the wrong places, a substantial amount
> of web surfing has yielded no detailed figures for RIAA Standard Equalization
> (regarding phono.) I was wondering if anyone would impart some numbers on me,
> should they feel so inclined. Someone may have come upon this if they were
> constructing a balanced moving magnet pre-amp, but I'm really not sure (as
> I've never done so.)
> 
> Thanks for your consideration and sincere apologies if this double posts.

Not even a month back (2003-04-17) I answered a question on this list relating
to NAB and RIAA corrections. The key-numbers is in there. So just looking in
the Synth-DIY archive should reveal some of the details at least.

Anyway, here it is:

From: Magnus Danielson <cfmd at swipnet.se>
Subject: Re: [sdiy] OT: NAB vs. RIAA?
Date: Thu, 17 Apr 2003 02:35:59 +0200 (CEST)

> > 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.

So, you need to make a Bode-plot using the 3180 us, 318 us and 75 us pole and
zero positions (you probably have a plot showing the curve, but there is really
just three numbers that specify it). If you need further help just let us know
and we could probably sort it out.

Cheers,
Magnus