Date:         Sat, 26 Aug 2006 22:04:50 -0400
Reply-To:     Association for Recorded Sound Discussion List
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Sender:       Association for Recorded Sound Discussion List
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From:         Charles Lawson <[log in to unmask]>
Subject:      Re: Non-RIAA preamp
Comments: To: Association for Recorded Sound Discussion List <[log in to unmask]>
In-Reply-To:  <001301c6c963$94e48f70$6901a8c0@TOMOFFICE>
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Tom Fine wrote:
>This is a very interesting piece of gear. I have DC6 but have not been
>overly impressed with its 
>DSP.

It requires quite a bit of tweaking to get really good results with some
DC6 algorithms.  The program can yield some *spectacularly* good results
on some source material, though.  WAVES and Algorithmix
de-clickers/de-cracklers are substantially better, IMO.  However, DC6 has,
on occasion, been able to tackle something better than the more expensive
options could.  Sometimes, you just gotta use all the tools in the box to
get a job done...

>Does anyone have experience transferring LPs flat and then applying EQ in
>the computer?

Yes.  I have used several different flat preamps including the one from
Tracer.

>Are you using this setup or something more ambitious?

It depends.  I did some experimentation using Millennia pres and a few
others of various flavors.  I have to confess having results from the
little Tracer preamp that were comparable to very expensive alternatives. 
The Tracer balanced preamp is pretty cheesy in its implementation (dual
block amps with RCA to eighth-inch adaptor cables--yuck), but is sonically
quite good--measuring out quite flat to nearly 100KHz with a respectable
noise floor (way better than any LP!) when battery powered.

>Does it sound appreciably better than a good phono preamp/cartridge combo?

This is very subjective, of course.  We all have certain kinds of sound
that we prefer and I have my own loves of certain cartridge/preamp
combinations.  My goal in my restoration work, though, is to get as close
to the original sound as possible regardless of what I may personally
prefer.  Doing a flat transfer and applying RIAA and at least one other
filter to flatten any residual nonlinearities in frequency response of the
pickup (whether that be laser or stylus/cartridge) in a computer after the
fact has served me very well--occasionally yielding results that I would
call spectacular.  I can make old LP restorations this way that sound
better than many CD re-issues of the same material because the analogue
master tapes have obviously degraded over time more than the LPs have.  I
have been quite surprised by this, since I previously didn't have that
much respect for vinyl overall.  However, I now understand what I used to
think was a backward idea that the BBC had of using vinyl discs as their
main archive medium.

I am definitely a convert to flat transfers + digital filtering after the
fact.  You can make certain that you are applying the exact same curve to
both channels (in the case of stereo), the filter doesn't degrade with
time as analogue component RIAA EQs will *and* you can easily alter the
curve very precisely to accommodate the many non-RIAA discs out there. 
(If you think it's important enough and you want to spend the money, you
can even get phase-linear digital EQs to handle the compensation curves
for you.)

I have yet to receive any customer complaints using this method.  It's
quite the contrary, actually.

As always, your opinion/mileage/experience may vary...

Chas.

--
Charles Lawson <[log in to unmask]>
Professional Audio for CD, DVD, Broadcast & Internet