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On Jan 9, 9:32 am, Rob wrote:
wrote:
I reccommed this book....

Elements of tape recorder circuits
by Herman Burstein
Published in 1957, Gernsback Library (New York)

It's an oldie but a goodie..
Lots of detail about EQ circuits, bias osc etc... nothing about Dolby
NR of course..

There were a few hits on the web, you may be able to download a copy..

You can indeed - and a very good read it looks too, thanks.

I like the bit on improving sound, or rather 'listening pleasure' -
should strike a chord or two ;-)

Burstein's book is indeed useful; in fact, I hand out bits of it to my
analog recording classes. But it suffers from a couple of problems.

The first is that it's really oriented toward consumer applications and home
tape recorders, which means its reference point is 7.5 ips recording. That's
a pretty different ballgame from 15 and 30 ips; the constraints are far
greater.

The second is that it was written fifty-plus years ago, and things have
changed a lot. Modern tapes respond a lot differently from the Scotch 111
that was the norm in 1957. For example, Burstein suggests that if 3% THD is
considered the overload point, 0 VU should be 6dB below that, and will have
about 1% THD. Older tapes did work like that: distortion increased steadily
until they hit the commonly-accepted overload point of 3% distortion. Modern
tapes have much lower distortion until just below the overload point, after
which the distortion level shoots up quickly. "Harder clipping" in the
modern vernacular. Modern tapes also do a lot better at avoiding
high-frequency saturation, and of course have much greater dynamic range.

Burstein also leaves out the problem of high-frequency losses due to tape
thickness, which was already understood to be the most important source of
high-frequency loss in the recording/playback process. (It had been
described by McKnight in a JAES article sometime in the early-to-mid-1950s.)

It's still a very valuable book, but it needs to be read in context. A good
modern supplement is the article on magnetic recording in Glen Ballou's
mighty tome, written by Dale Manquen.

Peace,
Paul