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Nagra Stories Sound-men won’t ever tell


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Hi again. 

Dela, the service manual is great, but unfortunately it does not cover any of the mechanical adjustments to the unit.

I would like to know about the mechanical adjustments now, because there is a slight problem with the left tension roller, with excessive wobble sometimes.

Is only a problem when there is a small amount of tape left on the supply reel, and the unit is stopped, then started again. The left roller keeps oscillating continuously unless I put my finger on it to stabilize it. If the tape is continuously played without stopping, there is no problem. 

Any ideas how to fix this ?  Would really prefer to fix this myself if possible, I am technically minded.


Thanks, Chris.


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I’m not a service technician so i can only respond in a general way but the problem you describe is common to the portable Nagras. I’ve experienced it with the IV-L, the 4.2 and the IV-S. The good news is that, once stabilized with your finger, the operation is good. Of course, it’s a nuisance. 


I think that service instructions for any portable Nagra ought to be applicable to your machine. Regrettably, I don’t have those manuals but they are likely to be more easily sourced. 




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David is right that it is a common problem with the portable models, but unfortunately the service manuals are not really informative about how to solve it...

The wobbling/oscillation og the roller is caused by the rather ingenious mechanical feedback system, where the left roller position is adjusting the left spool clutch. When the roller moves inwards (tape tension increases) the clutch is loosened (spool torque is decreased), because the movement of the roller is coupled to the clutch, using a metal arm between the two. It works really great if the clutch is working, but if f.ex. the clutch gets "sticky", the torque adjustment is not perfectly smooth, and you get the oscillation. The good thing is that it is not really serious (it usually goes away if you manually holds the roller, corresponding to dampening the mechanical feedback system). In my IV-S TC, which had been inactive for many years, it even disappeared by itself after a bit of use.


Getting rid of it involves taking apart the clutch and replacing the grass og the greased felt in the clutch; it can (probably) be done, but it is not for the faint hearted på apply new grease, as it is a one-way street: Once the original grease is not there, the regulation might get even worse... But it will probably be a good idea to start with making reversible changes, so adjusting the tape tension (on the adjustment screw on the clutch arm) might be a good start.

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Oops... I just checked with a scrapped 4.2 and discovered that I had mistaken left from right. The clutch is on the right reel, on the left reel the regulation is made with an adjustable brake. But the principle is the same, and actually the brake felt is a bit easier to check and replace on the brake than on the clutch system. But sorry about the confusion anyway...

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Thanks very much for the info, David & Dela !

Yes, the oscillating roller can be steadied ok with my finger.

I did not realize that this was a common issue with the Nagra decks. 

I will perhaps try adjusting the roller tension a bit with the adjustable screw on the arm. I guess if you removed the small return spring ( not the main tension spring ) that is attached to the left roller arm, this would stop the oscillation from happening ?  But then what would be the side affect from doing this ? 

Cheers, Chris.


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I am pretty sure that if you remove the return spring, the braking function will be really bad... If the spring is not pulling the roller outwards, roller will move inwards (and release the brake) with even a very low tape tension. If adjusting the spring does not work, you might try to dampen the return spring with f.ex. a bit of soft foam tightly around the spring (since the diameter is too small for putting the foam inside it). 



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Well,  I never had that problem on my 1962 Minico 3 inch recorder, the only recorder with a manual speed control on a rotating cam. 

This never needed any high price spring loaded bobbing crazy Swiss stuff.  It recorded test, test,  Merry Christmas,  testing 123 just fine. 
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Thanks for the reply, Dela.  I might try doing as you suggest.

I now have the service manual for the 4.2, it seems to be pretty much identical as far as the mechanical side of things go.

I will check the left reel brake pad material, and perhaps put a very small drop of grease on it as the manual suggests.




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Tension roller problem fixed !

I first tried adjusting the tension of the return spring (very nice screw mechanism to do this, by the way), this helped a bit, but not enough. 

So I returned the tension adjustment to its original position, then added a very small amount of oil on to the brake drum itself, but not directly on the felt pad.

This fixed the problem. Now, at the end part of a tape, the left roller starts to oscillate a few times, then quickly stabilizes, after stopping then starting again.

Much happier now ! 

Cheers, Chris.

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Hello again :)


To Sound-men would you say you used a mono Nagra, for film sound, longer than the Nagra stereo? I would be interested to know how long you used a mono Nagra machine in comparison to a stereo Nagra.

Also when was it when the digital framework began to interest you? How long was it till you moved from analogue to digital?

What about microphones? Did the technology develop in parallel?


All the best


REQUEST: Nagra Mastrclass Video's


If any of you master's would be interested in a walk through of how you used to or still do setup your Nagra, I would love to see any video's. General Setup and Tips and Tricks please. Always here to learn!!



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  • 3 weeks later...

Hi Mark C,


I used my two Nagra 4.2 recorders for 13 years for drama and documentary work.

I regularly aligned the machines to achieve the best possible performance using a

Nakamichi T-100 audio analyser.

For me the 4.2 was the ultimate recorder with all the facilities you needed.

I built my own KAT unit (which added a 3rd microphone channel) and I added

a 48v phantom setting to it unlike the Nagra version.

I used a Nagra 4STC for Cousteau expeditions for 4 years.

Although it offered time code and two channel recording, I realised that it's noise performance

did not match the 4.2 due to it's two narrow tracks with a guard band.

I also felt that the headphone amplifier was not as good as the 4.2.

I move to DAT in 1993 then to hard disk in 2004 and on to CF and SD cards.


Microphones did not immediately develop quickly, I had worked with high quality condenser

units since 1966, the Sennheiser 804 was a breakthrough in directional microphones and the

next significant leap forward was the Sony ECM-50 electret personal microphone around 1974.

Currently there are many great electret personal microphones for use with radio systems.

A very innovative Japanese manufacturer Sanken now sell an interesting range of electret units.

In the last 15 years SoundField microphones allow recordings that can produce 5.1 results.

I own an SPS-200 that has achieved stunning results with a full orchestra


The greatest  audio developments were in radio microphones with Audio Ltd, Sennheiser and then

Lectrosonics as UHF transmission developed plus pre-emphasis then double ended compansion systems

and currently digital systems that offer remarkable dynamic range and quality.


I will try to find my measurement and test sheet for the Nagra 4.2



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I used various mono Nagras (III, IV-L, 4.2) between 1975 and 1984.  By 1984 my clients had become interested in having timecode recorded on the recorder along with audio, to allow for automated and faster syncing of sound to a video tape copy of the film shot on location, and that was really only practical with various modifications of the IV-SL.  As Mike said, while the IV-S is a great machine and has 2 audio channels, it has far fewer features useful to location recordists and thus required a lot more peripheral devices to get the job done.  I used IV-S recorders modified with various time-code add-ons up through the "Harvey" or "Time Code Systems" conversion--which I still have (which came out about a year or so after the Kudelski IV-STC).   I started using digital recorders (DAT) as soon as they became available in the USA in "grey-market" versions (while official imports from Japan were held up by the record industry) in the late 1980s--these were non-timecode recorders that came along at a very convenient time for the overseas nature and culture docs I was working on then.  They were far lighter, smaller, cheaper and had tape run-times far longer than Nagras--great for travel.  Time code DATs came a bit later, were highly complex and trouble prone and grossly overpriced, in my opinion.  Again, clients requested their use, in spite of generally inferior sound compared to 1/4" Nagras.   In the early '90s early adopters of file-based recorders, such as Jeff Wexler, began to campaign to get acceptance of machines like the Deva II, followed a few years later by Sound Devices and other machines, as well as laptop-based recording systems like Metacorder.

The industry switched to file based recording pretty quickly, as DAT seemed to become more troublesome as the machines aged and computer-based post made the delivery of audio files instead of tapes very attractive.  Most younger people I work with on crews today have never been on a film or a tape-based video shoot, and have never used a Nagra or a DAT machine--the transition has been pretty widespread and complete.  Nagras are still used by some music engineers for certain projects, that's pretty much all the Nagra reel to reel usage I hear about anymore (besides being a prop in a period film).

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Just got my next "new" NAGRA for my collection but need help from the community. The new income is a NAGRA ARES-C with flash card as storage medium.  The seller told me it's dead, and its true. To fix it I desperately looking for the service manual or at least the schematics for the unit. If anybody can help me out it would be great. 

As second I need the Windows based software from NAGRA to import the recorded music from the NAGRA ARES-C.

Nagra used a special format on their PCMCIA Flash Cards.

The only thing I know about this software is the name what was stated in the owners manual.

(Called ARES-95 or ARES-NT)

I promise I will make picture and put it in the forum. (Next couple of days)


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Hi Guys.

As Mark said, this is very interesting historical info, thanks for sharing !

I still love using my Nagra E. I have added a QTIM timer roller to mine now which is quite handy, and pretty accurate.

I sometimes play it in the car, through the car sound system, is wonderful !


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10 hours ago, MarkC said:

Hello again,


From a technical perspective, can a IV-S operate timecode with the less common wider stereo record and playback heads?


I haven't seen any examples around.

As always, thanks in advance.






Unfortunately no; the TC track lies in the middle of the tape between the two audio tracks, so if there is no wide guard band between the tracks, the TC signal will overlap the audio tracks. I don´t know that much about the Harvey TC implementation, but that also relies on a middle track...

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I got myself neopilot 4.2 with Nagra QGX crystal sync generator built in. However I don’t know if it’s broken or just I don’t know how to use it. I have an XTAL plug in pilot socket. When I turn machine into the test mode pilot flag indicator turns white. But since I turn machine into recording pilot indicator turns black and it doesn’t record pilot signal. Modulometer shows pilot frequency at 0% for the whole time.


Has any of you experienced Nagra users idea what can be wrong? Maybe I am omitting something or it is damaged?


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