On Tue, 10 Mar 2015 09:39:00 +0000 (GMT), Jim Lesurf
wrote:

In article , Java Jive
wrote:

After some searching I've just found some AC recordings of tracks from
an album that I now have on CD, it's Barbara Dickson's seminal folk
album "From The Beggar's Banquet", 1970. The AC recordings were
originally made from a library copy of the LP, while the CD is a
re-issue of 5 or 6 years ago that I feel most fortunate to have
obtained. The difference between the two is utterly unmistakable.

Alas the LP and CD come into that if you're trying to assess AC.
Particularly if you've not heard the LP for a long time and become
habituated to the AC.

Of course, but equally, I have several digitisations of vinyls of
similar material and sound, digitised on the same deck with the same
cartridge, and they too are way better than these AC recordings. Also,
I have both a commercial AC and a rather worn vinyl of Eddie Walker's
"Red Shoes On My Feet", and, even though worn with a great deal of
needle-in-the-groove noise, the vinyl is otherwise still way better
quality than the AC. From this and many other historical AC
recordings now replaced from better sources, I know that the big
problem with AC is the slow tape-speed, leading to the poor FR, and
the narrowness of the tape which contributes to a generally poor SNR.

FWIW I also routinely find that an LP sounds different to a CD of the
'same' material. The problem being that this may be down to the two
versions being 'mastered' sic quite differently. Can tell you more about
the people cutting the LP or 'improving' sic again what they put on LP
than it does about the frequency response capabilities of either system.

Yes, yes, we've been here several times before, and generally tend to
agree on the topic.

All comes down to how much care and skill were applied when producing the
LP or CD, and to the replay systems.

As I said at the top of this sub-thread, but care can not make up for
the low FR of AC, a constraint arising out of its slow tape-speed.
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In article ,
Java Jive wrote:
As I said at the top of this sub-thread, but care can not make up for
the low FR of AC, a constraint arising out of its slow tape-speed.

Commercial cassettes were usually duplicated at high speed. So never going
to be at the top end of even that lowly format.

Cassettes made on a good home deck using top quality tape could be
remarkably good, considering.

--
*Ever stop to think and forget to start again?

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 11 Mar 2015 01:19:07 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Java Jive wrote:
As I said at the top of this sub-thread, but care can not make up for
the low FR of AC, a constraint arising out of its slow tape-speed.

Commercial cassettes were usually duplicated at high speed. So never going
to be at the top end of even that lowly format.

Cassettes made on a good home deck using top quality tape could be
remarkably good, considering.

Not too difficult to achieve considerably higher quality than
commercially recorded music cassettes given a reasonable quality
cassette deck and chrome/SA tape formulations (let alone metal tapes
with Dolby noise reduction with the better decks) when you consider
that the duplication process was often run at 8 times speed and even
as high as 16 speed in some cases.

I'm not sure what the maximum duplication speed was, possibly as high
as 32 speed for audio book recordings were the lower demands for good
quality speech allowed the duplicating equipment to be pushed to its
limits[1] without any obvious degradation becoming evident in the
playback.

As the saying goes, "Time is Money" and there was every temptation to
run the duplication plant as fast as possible, often a choice of 8
speed over quad speed on older kit and probably 16 speed in place of
the 8 speed option on the newer and improved duplicators (where the
16, and possibly 32, speed was intended for audiobook quality alone).

[1] The real limits were down to heating effects and saturation of the
magnetic cores and pole pieces of the special 4 track recording tape
heads used by the slave drives to transfer the master in a single
pass.

Notably the nominal 60KHz bias current being scaled up to 960KHz for
a 16 speed transfer rate. In this case, it was the limits of the heads
that defined the maximum peak limits of the recordings rather than the
limits of the tape formulation itself which would normally be the
limiting factor on a cheap deck's performance at real time speeds.
--
J B Good