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..

I was, thanks.

Daniele
--
Your chance to own a nearly immaculate BMW C1 (Cardiff, UK)
http://search.ebay.co.uk/220341650190

"David Looser" wrote in message
...

"Paul Stamler" wrote in message
...
"David Looser" wrote in message
...
"Paul Stamler" wrote in message
...

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.


Do you do classes in acoustical recording as well?

Yes.

Why? who does acoustical recording these days?

The Edison National Historic Site, for one.

We study the technical aspects of acoustical recording, not because any of
the students expect to do it, but because it helps place into perspective
the technical, and social, and economic, and musical issues which have
shaped recording and the recording industry.

The analog recording class is an entirely different story. Our students
learn the technical and practical aspects of analog recording because it's
still being done, particularly at the higher ends of the food chain, and a
student who knows not only how to use an analog recorder but also how to
calibrate it properly has a leg up in getting a job in the industry.

Peace,
Paul

"David Looser" wrote in message
...
"D.M. Procida" wrote in
message
...
Dave Plowman (News) wrote:

I remember a cheap tape deck in the '50s that had no capstan - so the
tape
speed varied with the amount on the reels. Disaster if you broke the
tape
and had to junk some.

There were literally dozens like that in the 50s and particularly the
60s. They are known as "rim-drive" decks. They all had horrendous sound
quality; it's not a mechanism suited to the purpose!

They were novelty toys, really. I think they all came from Japan, from
just a very small handful of factories who sold them under a vast array
of more or less plausible western-sounding brand names.

As well as being cheap, they could be made very small.


I remember them well. They used to be extensively advertised in the small
ads in the back of "Practical Wireless" and the like.


Wasn't there a thing in the fifties called "GramDek" or something like that
which you put on the turntable of your Dansette to convert it to a tape
deck?

Geoff

"Paul Stamler" wrote in message
...

Why? who does acoustical recording these days?

The Edison National Historic Site, for one.

That's industrial archaeology, rather as a blacksmith might make a sword
using the technology of the Iron Age. The object of the exercise is to
fill-in the gaps in our historical knowledge of the techniques involved now
that those who practised this art for real are no longer with us.

We study the technical aspects of acoustical recording, not because any of
the students expect to do it, but because it helps place into perspective
the technical, and social, and economic, and musical issues which have
shaped recording and the recording industry.

Clearly the early history of the recording industry was significantly
constrained by the fundamental limitations of acoustic recording technology.
But there is a huge difference between teaching the history of a technology,
and teaching it as a skill to be used. The implication of the answer "yes"
to the question "do you also teach acoustical recording" was the later,
actually you teach *about* acoustical recording.


The analog recording class is an entirely different story. Our students
learn the technical and practical aspects of analog recording because it's
still being done, particularly at the higher ends of the food chain, and a
student who knows not only how to use an analog recorder but also how to
calibrate it properly has a leg up in getting a job in the industry.


My initial response to the thread was prompted by the way analogue audio
tape recording was being discussed as though it was still "state of the
art". Reference was made to "modern" tape formulations, how old are these
"modern" tape formulations?, 20 years?, 25?, hardly "modern". The
manufacture of analogue tape machines has effectively ceased and the number
of manufacturers of analogue audio tape has dwindled to a two or three each
making only one or two types, this is a dying technology. I realise that a
few studios still offer analogue recording to those clients who like
distortion, but it is a kind of technological ludditeism.

David.

"Geoff Mackenzie" wrote in message
...


Wasn't there a thing in the fifties called "GramDek" or something like
that which you put on the turntable of your Dansette to convert it to a
tape deck?

There was, and it was advertised in full-page adverts, not the small ads.

It fitted any normal record deck. It consisted of a metal plate carrying the
spools with the heads and capstan in between which fitted over the spindle
of the turntable, with a fixture to prevent the whole thing from rotating.
The capstan was driven by the turntable, at 45 rpm the tape speed was 7.5
in/sec, other non-standard tape speeds were available on a multi-speed
record deck. Finally a small battery-operated box contained the pre-amps and
bias osc (erasure was by permanent magnet). The user had to contrive somehow
to connect the audio from the pre-amp to the record player's (or another)
main amplifier.

How well it sold I don't know, but it was heavily advertised for several
years.

David.

Geoff Mackenzie wrote:

Wasn't there a thing in the fifties called "GramDek" or something like that
which you put on the turntable of your Dansette to convert it to a tape
deck?

Gramdeck - I'm sure I saw one on eBay recently.

http://www.johansoldradios.se/tape-recorders/gramdeck

Daniele
--
Your chance to own a nearly immaculate BMW C1 (Cardiff, UK)
http://search.ebay.co.uk/220341650190

David Looser wrote:
My initial response to the thread was prompted by the way analogue audio
tape recording was being discussed as though it was still "state of the
art". Reference was made to "modern" tape formulations, how old are these
"modern" tape formulations?, 20 years?, 25?, hardly "modern". The
manufacture of analogue tape machines has effectively ceased and the number
of manufacturers of analogue audio tape has dwindled to a two or three each
making only one or two types, this is a dying technology. I realise that a
few studios still offer analogue recording to those clients who like
distortion, but it is a kind of technological ludditeism.

Perhaps, but it still sounds good, it's still billable, and there are still
plenty of customers demanding it. Equipment and media production have
dropped down to stable levels to support the low but constant demand of
the market. I don't see it expanding, but I don't see it going away either.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Dave Plowman (News)" wrote in message
...
In article i,
Iain Churches wrote:
Indeed - the 'BBC' way I was taught on setting bias in the early '60s
was to increase the bias until the level peaked (using 1kHz tone) then
carry on 'till it dropped by 1 dB. Which was a reasonable compromise
for the standard tape the BBC used in those days.


Later, a 10kHz tone was used, and bias set at 3dB over peak.
This was recommeded by AGFA for PEM468.

Indeed -

Well actually, in practice 3dB over at 10kHz was quite close to
1dB over at 1kHz, but the larger movement of the meter needle
was thought to be easier to follow with accuracy.

but the practice I was taught was from the days when machines
struggled to make 10kHz on BBC standard tape.

Surely they were not that bad?

Magnetophon tape machines were -2dB at 15kHz in the 1950s

I wonder how they set the bias for wire recorders? :-)

Iain

"Serge Auckland" wrote in message
...

"Iain Churches" wrote in message
ti.fi...

"Dave Plowman (News)" wrote in message
...
In article ,
Paul Stamler wrote:
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.

Indeed - the 'BBC' way I was taught on setting bias in the early '60s
was
to increase the bias until the level peaked (using 1kHz tone) then carry
on 'till it dropped by 1 dB. Which was a reasonable compromise for the
standard tape the BBC used in those days.


Later, a 10kHz tone was used, and bias set at 3dB over peak.
This was recommeded by AGFA for PEM468.


When I worked for Rediffusion in the early seventies, there were heated
discussions between the maintenance people and the sound engineering
people as to the correct bias setting: 1dB overbias, 2dB or 3dB....we
obviously didn't have enough work to do.....

It's an important basic parameter which surely should have been
established and stated in black and white. At Decca, such decisions
were arrived at by discussion between the recording staff, R+D, the
tape manufacturers etc.

3dB over at 10kHz was our standard for setting bias.
The 2E used to set up the next two reels of tape on
the second set of A + B recorders, with a remote oscillator
and meter, so that there was no delay when the reels in use
came to an end.


The tape machines were Philips Pro 50s

I liked those. We had several in mixdown and copying
facilities.


Ampex AG440s, both using Scotch 206.

Did you likethe AG440? Compared with Studer they
were pretty flaky IMO. When I moved to RCA we
had an Ampex multitrack. On a big (expensive) session,
we used to insist that a maintenance engineer with hot
soldering iron and a box of spare cards, sat besides the
machine for the whole session.

Happy days....

Indeed. Flying by the seat of one's pants!
It was fun!.

Iain

"Dave Plowman (News)" wrote in message
...
In article ,
Iain Churches wrote:
The 1950's were a very interesting time in tape recording.
I can remember a 76cms Magnetophon recorder on which the
erase head got so hot that it would burn a hole in the tape
when the transport was not moving, if you did not put a
match stick between.

Surely the EMI BTR series were around by then - to all intents and
purposes a modern tape machine?

Was the BTR1 a predecessor to the TR90 ?
I remember well the BTR2, and also the BTR4
which came out circa 1966 (whatever happened to the BTR3?)



IIRC, the Magnetophon dates from the
early '40s - and was the basis for the EMI BTR1.

Yes. The Magnetophon was the machine that the Allies
brought back from Germany as part of the spoils of War.
It had baffled the Allies for some time that the Germans
were able to broadcast pre-recorded speeches by
Hitler from Berlin without give-away disc noise, and put them
out as supposedly live transmissions, when it was known for
certain that he was elsewhere.

Arthur Haddy stated that the Allies brought back four
Magnetophon machines, two of which went to what became
Ampex in the USA, one to EMI at Hayes, and one to Decca.

Nothing beats a real "high tech" solution:-)

I remember a cheap tape deck in the '50s that had no capstan - so the tape
speed varied with the amount on the reels. Disaster if you broke the tape
and had to junk some.

Wonderful!

Iain