请教小南瓜的几个问题

LeeNY · 发表于 2012-10-12 09:08:45

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6357165 开友问我关于Nagra 4S, 4STC, 4S-JC的技术特点,以及在发烧及专业上的应用等,我觉得还是请教红灯,泡泡,演奏播放等专业或资深烧友,能得到較专业和全面的解答,谢谢.

波仔 · 发表于 2012-10-12 14:13:32

坐在沙发等听课

爱乐无忧 · 发表于 2012-10-12 15:57:15

坐在沙发等听课

我拿个板凳{:4_213:}

红灯记 · 发表于 2012-10-12 21:43:10

作为专业领域的便携式开盘磁带录放机，南瓜4系列是佼佼者，以4.2和4s为典型代表。从我使用、维修过的南瓜机器以及手头上掌握的技术资料来看，4S的几个衍生款式差别不大，没有后缀的机器录音电平旋钮与有后缀的结构不一样：没有后缀的平淡，有后缀的气派好看，其它有啥本质上的差别，我还没发现；录音效果很棒，放音效果与其录音效果相比差距不小。当年它的主要使用场合是电影摄制过程中的室外录音，同步录音技术很成熟，室内很少有使用它的。广播领域有用但不多，由于价格昂贵，被后来的日系SONY的NATIONAL的便携开盘取代。

LeeNY · 发表于 2012-10-12 22:33:35

就是说在4S基础上加入time code技术的4STC并没有质的飞跃,SJ也进步不大.

红灯记 · 发表于 2012-10-13 12:13:07

LeeNY 发表于 2012-10-12 22:33

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就是说在4S基础上加入time code技术的4STC并没有质的飞跃,SJ也进步不大.

time code 的加入，使机器具备了time code counter 的功能，便于循迹剪接，这在模拟磁带记录史上就是一个很大的进步，使之在影录音制作领域很受欢迎。人性化、艺术性的设计构思，既是一件实用的工具又是一件完美的艺术品，一直受到人们的热捧。我认为它优质精密的直流主导电机和用人造宝石阻尼伺服系统是其精确控制走速的先进所在，尤其是它那独一无二的表头，夜色里就像美少女的大眼睛，随着音乐在闪动，勾人心魂令人蠢蠢欲动...

红灯记 · 发表于 2012-10-13 12:22:30

4s应该都有时钟码功能，看有没有配置。录音放音磁头中间的就是TC头，下面图片来自于百度搜索有裁剪

LeeNY · 发表于 2012-10-13 18:10:14

本帖最后由 LeeNY 于 2012-10-13 18:15 编辑

[color=#脚印留下*^_^* ]红灯记发表于 2012-10-13 12:13

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7 X/ X- {# U7 Q3 W7 atime code 的加入，使机器具备了time code counter 的功能，便于循迹剪接，这在模拟磁带记录史上就是一个 ...

精采!{:4_219:}

请讲讲SJ

红灯记 · 发表于 2012-10-14 03:16:51

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Uher's range of portable audio recorders were for perhaps over 30 years, the reliable 'work horses'
of the professional radio interviewer. German made and of 'sensible' and real world construction,
these robust machines cost a fraction of an equivalent Nagra or Stellavox recorder.

While the film maker might need Pilot Tone synchronization, 48 Volt 'phantom' condenser
microphone powering, or even time code, the hack radio reporter just needed a good quality,
strong, simple and reliable tape machine with a basic dynamic microphone input. And while there
were a few alternatives to these machines from the likes of Tanberg, Ficord or even Grundig, the
Uher Report series became the de facto portable tape recorder standard for radio reporting.

Actually these machines were not all that cheap, and cost perhaps the equivalent of a serious
domestic 'Hi-Fi' tape-deck of the time. (The Nagras and Stallavoxes were many times this though.)

Actually this half track stereo recorder is a later version of the 'genre', and has improved metering
and internal electrical switchery. It has four speeds, though for serious work only the highest (7.5
inches per second) speed should be used. The lower speeds become less and less useful, but
speech recording at 3.75 I.P.S. would be perfectly OK for most broadcaster's use. While of
comparatively elementary mechanical design, these machines can make surprisingly good
recordings at 7.5, seemingly just as good as a Nagra or a Stellavox at this speed. They also record
rather well at 3 and 3/4 inches per second, but speed stability and 'wow and flutter' (how arcane in
theses digital days) is nowhere near as good as with the Swiss exotics. Remarkably, one can set the
bias up on these machines 'by ear' for indistinguishable record / replay results (yes I know this is
cheating), which you cannot do as easily on the Swiss machines, for probably good reasons. As a
reel to reel audio recorder the only, though fairly significant drawback, is a limited recording time
of 20 minutes on the highest speed. Though for radio interviews that would be edited into sound
bites anyway, this was not a problem.

Over the years Uher made a whole range of semi-professional tape equipment, audio and even Hi-
Fi equipment, much of which for domestic consumption only though. They even made a couple of
versions of a high quality (if there ever was such a thing in the context of serious audio) portable
Compact Cassette recorder. But while Uher are still involved with dictation equipment, they will
probably be remembered in the history books for these robust and reliable portable reel to reel
machines.

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(The previous owners of the above example of the stereo version have fitted a plastic collar
around the master level control so that it could only be adjusted by means of a screwdriver - seems
a sensible idea, so I kept it there.)

红灯记 · 发表于 2012-10-14 03:18:49

The Nagra IV-S Portable Audio Tape Recorder

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What can one say about what is probably the most successful and long lived portable professional tape
recorder ever made? Certainly the 'Nagra' was a legend in it's own lifetime, and remains an object lesson in
quality of engineering together with remarkably simple and unpretentious functionality. Beautifully made and
until just a few years ago just about every film and television programme produced had its sound recorded
on one of these impeccable machines.

Nagra portable film sound recorders similar to the above machine became the de facto industry standard for
more than a quarter of a century, and were only gradually edged out of use in the last few years by firstly;
compact R-DAT recorders, and now by various short-lived and almost disposable file based devices. As
with professional video, the new technology seems to be doing anything but establishing any industry
certainly or commonality of format.

The Nagra IV-S shown above is an immaculate late time code machine type NQS-TCC, which might indeed
be still available new from the factory, and I wish it was part of my own collection...

The June 1989 Audio and Video Product Line catalogue describes it thus:

'The NAGRA IV-S is a portable self contained 6.35mm (1/4") tape stereo recorder designed for high quality
musical recording, cinema and television applications. It has three speeds: 38, 19 and 9.5 cm/s (15, 7 1/2
and 3 3/4 ips) NAB or CCIR, plus NAGRAMASTER (38 cm/s only / 15ips) equalizations. The machine has
two microphone inputs with three pin XLR connectors, switchable between dynamic, "T" or Phantom
powering, with phase check, and left channel phase reverse switch, or two current line inputs. It also features
a NAGRALIN antidistortion system, high pass filters for recording or replay, and a switchable automatic
level control and limiter. Built-in loudspeaker, and headphone output and reference signal generator. The
machine can be fitted with a NAGRASYNC F.M. 50/60Hz pilot system or the SMPTE/EBU centre-track
time code system, including a built-in time code generator, for synchronizing. Other accessories are
available for particular applications.'

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Above is the tape head area, moving from left to right we have; the dual-gap ferrite erase head, the time
code record/replay head, the audio record head and finally the audio playback head. In this photograph the
tape path has been opened for lacing and the hinged audio head screening shields are folded down. One
might like to appreciate the substantial tape guides and the massive stroboscopicaly marked flutter idler
wheel. Every component looks simple, honest and beautifully engineered. This version of the machine uses
a later type of tape guide which have a slightly textured though very hard white ceramic face plate, together
with (unique?) ruby rod end stones. Apparently the ceramic face plates replaced solid polished slices of
synthetic ruby used in the previous version of these guides because it tended to cause a slight stiction or
judder effect with the tape which could increase scrape flutter. Visible just in front of the central time code
record/replay head is the unique Nagra azimuth adjusting device. This consists of a pair of very slightly
wedged disks sandwiched under each record and play head, one was fixed to the deck plate and the other
had a geared circumference. To adjust the head azimuth one just turned a small socket headed gear wheel at
the front of the head with an Allen key, and this rotates the two wedges against each other, thus rocking the
head back and forth. As far as I am aware this system was fitted to all Nagra portables, though can't recall
if it was used on the T-Audio.

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Left side of the Nagra IV-S, containing the various noise-reduction and line inputs and outputs, together
with the XLR microphone inputs and their powering mode and attenuator switches. One of the many nice
touches are the slotted carry-strap 'keepers' (extreme left).

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Right side of the Nagra IV-S showing the loudspeaker grille together with the various power and time code
connections.

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And if you ever wanted to know what the underside of a Nagra IV-S looked like... (The rectangular
door is the simply fastened battery cover, which can, if you don't keep hold of it, just fall on to the
floor.)

红灯记 · 发表于 2012-10-14 03:23:01

The Stellavox was the only true alternative to the Nagra portable audio recorder.

Also made in Switzerland and reputedly by some ex-Nagra employees, these machines were more
compact, rather better finished and felt perhaps more developed than the Nagra. It was as if Nagra
had left their own masterpiece slightly unfinished and that the Stellavox was something of an
advanced refinement. But things are never that simple and in addition to the interesting
relationship that existed between these two companies, their products also show quite strongly
differing personalities. As an amateur enthusiast I was inclined to think that the Stellavox was the
best portable reel-to-reel recorder ever made. It certianly was a very expensive and rare beast,
and when I had the opportunity to acquire one of these Swiss portable recorders, it was a
Stellavox that I went for. However, I was not going to earn my living with it or try and build a
reputation with one. But I imagine that many professionals did, and having had the chance
reciently to re-acqiaint myself with some Nagra machines, I concluded that they were just
differing 'solutions' to a similar set of problems. Unfortunately I did not have the opportunity to
compare their audio quality, but have included their specifications on the site.

An impression might be formed that the smaller and more compact Stellavox recorder seems to
contain rather more contradictions in it's make up. I believe that it was not as well accepted in the
film industry or as widely known generally (though this could be down to discontinuities of
representation, at least in the UK). but they were used when a highly portable, non sync but high
performance audio recorder was needed. Like the Nagra, variations of the Stellavox were made
for multi-channel instrumentation recording, and there were versions for 4 track 'Quadraphonic' as
well as higest quality stereo mastering (this version was known as the 'Stellamaster'). Subject to
encouraging though mixed reviews by Hugh Ford in Studio Sound in the early 1970's, to use a
Stellavox was to be rather 'diffrent', which perhaps was also part of their attraction. However on
these pages are examples of both the Nagra and the Stellavox, so perhaps some own conclusions
may be drawn.

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The above picture is my own Stellavox SU8, and this was one of the last models from the
original Stellavox company, this particular example dates from the mid 1980's. The 'U' stands
for universal, because this version of the recorder came 'loaded' with a full range of modules
and options as follows:

MSP module - switchable mono, stereo, 'snchrotone' and 'neopilot' head assembley

SXQ module - crystal pilot tone generator

SQS module - in-built synchronizer module and associated front panel controls

SOT option - balanced 600 Ohm input/output transformers and seperate connections.

AMC tape counter unit

The recorder also has switchable 48V phantom or 'T' microphone powering together with a two
position low frequency microphone filter, peak limiters and three position gain attenuators
(these were fairly standard options I beleive). The microphone gain controls have the optional
'ganged' gearing arrangement, and can be mixed with adjustable line inputs. Stellavox also made
a recorder powered external microphone pre-amplifier (and various other external modules), so
that one could have a fairly self-contained set of 4 microphone inputs if required. Oh, and the
moulded plastic reel cover had the machined-satin-chromed 'thingy' fitted, for actuating the slate
toggle while the machine is sitting in it's leather case.

The recorder's specifications may be found here.

Portable Reel-To-Reel Audio Tape Recorder

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The father of the Stellavox, Mr Georges Quellet himself was kind enough to send me this image of
his earilier SM5 recorder*.

It would seem that in 1950's in addition to those in America and Britian, a number of people in
Switzerland were also developing high quality reel-to-reel magnetic tape recorders. Whereas Mr
Studer would go on to produce his superb professional full size machines, Stephan Kudelski and
Georges Quellet made far more 'pocketable' tape recorders. As a school boy I can also just
remember the British Fi-cord brand of minature audio recorders, though 30 years later I found out
that these tiny exotic machines were also made in Switzerland (by Georges Quillet it would
appear). It was though perhaps obvious that the combination of minature electronics and precision
mechanics needed to make a high quality tape recorder would suit a country also known for
watchmaking, and one could argue that the end results would be some of the finest examples of
20th Century electro-mechanical engineering.

* It is possible that he will collaborate in a book about hs machines, do please let me know if you
think this a worthwile project and I can advise the author.

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红灯记 · 发表于 2012-10-14 03:25:11

More like an excercise in watchmaking than an audio recorder, the increasingly collectable Nagra SN is
yet another delightfully tactile object from this famous Swiss company.

Mr Tim Blackham's very early and un-legeneded example is shown above on the Left, and my own later
full track mono* version is shown lower Right. These truly pocket sized and light weight reel-to-reel
tape recorders were in actual fact true professional sound recorders in every respect, and were a very far
cry from almost every other similar sized tape recorder. While various 'toy' miniature tape recorders of
the 'Misson Impossible type' produced results varying from excruciating to just plain bad, this little
Nagra gave real Hi-Fi quality. Actually I sometimes use mine into an HH AM8/12 amplifier and a
Tannoy Monitor Gold in a Lancaster cabinet with pretty impressive results!

With built-in 50 Volt capacitor microphone powering and a proper capstan servo system, the Nagra SNN
was quite capable of making studio broadcast quality recordings at the relatively low speed of 3 3/4
inches per second on 1/8 inch wide tape. (Which was actually re-reeled Compact Cassette tape - see
below.)

Perhaps more famous for its 'security applications', this 'spy Nagra' was often used as a concealed film
location recorder before the arrival of reliable radio microphones. Simple in use; you just plugged the
microphone or line input lead into the machine to put it into record mode. It didn't have fast forward, and
rewind was done by hand by turning a miniature fold out 'starting handle'. But this rather quaint feature
was perfectly usable and saved the batteries.

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The Nagra SNN Minature Audio Tape Recorder

Above is another view of Mr Blackham's unusual Nagra SNN. As far as I can see, apart from not having
the various anodised legends on the deck plate, also absent are the adjustable AGC threshold knob and
the transport lock-out 'switch' next to the meter. The cover 'hinge' arrangement differs slightly from later
machines, as does the 'patina' of the anodised finish. A most interesting version, has anyone got another?

(Apparently yes, I have recently been advised.)

Click on either of the above images for more information.

* For those who are looking at the stereo versions of this recorder often to be found on 'Eday', do
beware, as It is unlikely that these will be the recent versions designed to record high quality music.
There are now apparently four versions of the Nagra 'SN':

Nagra SNN - full track recording at 3 3/4 and 1 7/8 i.p.s. - high quality recording in Mono

Nagra SNS - half track recording at 1 7/8 and 15/16 i.p.s. - surveillance quality recording in Mono

Nagra SNST - Stereo recording at 1 7/8 and 15/16 i.p.s. - surveillance quality recording in Stereo

Nagra SNSTR (recent) - Stereo recording at 3 3/4 and 1 7/8 i.p.s. - high quality recording in Stereo

Apparently for covert surveillance use it was preferable to have two separate recording channels to
have some chance of capturing a muffled or distant conversations. So these older stereo machines will
therefore be optimized for speech recording only, and will also run at low speed for maximum
recording time and not fidelity. Actually Nagra made a special playback loudspeaker system (25100
DSP) with built in equalization to compensate for the quite limited frequency response of these
recorders. A standard mono Nagra SNN running at 3 and 3/4, like the ones on this page are capable of
truly Hi-Fi recording, but the slow speed SNS and the SNST stereo versions are not. Perhaps it might
be possible to convert these machines for Hi-Fi use, but this would involve replacing most of the
electronics and be very expensive.

Cheaper to buy a rather better stereo IV-S in the first place!

Tape for the Nagra SN

I have been amazed at the prices some people have been willing to pay on that wild west auction site for
the little reels of tape for this machine. When I first acquired my example from the BBC naturally I
wanted to play with it and make some recordings. I knew that the tape was basically re-reeled cassette
tape so I approached a tape duplication house in the UK and quite easily obtained a few part used
'pancakes'. These are the un-flanged bulk reels of tape (about 10" dia) that are automatically wound into
the cassette shells. I then contacted Nagra UK (always helpful) and obtained for around ?5 each
several pairs of empty plastic reels. It then was quite a simple matter to wind tape off the pancake and
onto the Nagra plastic reel (by using the hand crank on the machine). I did this a few years ago and
things may be slightly different these days, but perhaps worth investigating rather than spending some
VERY silly money.

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6-Inches

6357165 · 发表于 2012-10-29 10:51:43

多谢卢老师的解答,很详细.

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