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Re: External preamp for Marantz PMD 661?

Subject: Re: External preamp for Marantz PMD 661?
From: "Avocet" madl74
Date: Mon Mar 18, 2013 12:16 pm ((PDT))
> While one can always add gain in post, there's something to be said
> for staying away from the bottom few bits in an inexpensive ADC &
> getting the majority of the signal to hit the upper 40 - 50 dB of
> the available dynamic range.

The delight for me going to digital from tape is that you can
undershoot without penalty. The BBC line-up standard on 16 bits
was -14dB peaking 6dB above that. I record at least 15dB below 100% on
my affordable Tascam DR-100 and any digital noise is well spamped by
the (low) mic noise.

Peaking at -18dB below max, you still have a dynamic range of 10 bits
at 6dB per bit above the 3 bits peak of digital "dithering" which my
Tascam shows. This is easy to check by getting down to the individual
samples with the sound editor with "zero" mixer inputs. Natural 
background noise here in a very quiet valley swamps the mic noise, let 
alone the digital noise in the low bits.

The joy is that I don't lose the unexpected peaks to the limiter
except for close thunder. My choice is to mess about in post
production bringing the level up to peak at -6dB to -3dB rather than
hit the limiter and ruin thet track.

David

David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce







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