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Nagra Stories Sound-men won’t ever tell

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Thank you for fast response. I made some test recordings and when replaying with pilot playback chosen modulometer’s needle moves very little. Also I have some tapes recorder with 50Hz pulse sync and again modulometer reacts in the same manner. It oscillate around % mark on the meter.

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On 10/29/2017 at 8:26 PM, dela said:

 

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...

Hi Dela,

As a matter of fact I do have a X4S modded machine. So I assume this machine was originally NQS-L. If I wanted to put wider stereo heads on and did not use the pilot tone/timecode function would it work without any circuitry changes as an NQS-LSP would?

Thanks

MarkC

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28 minutes ago, MarkC said:

Hi Dela,

As a matter of fact I do have a X4S modded machine. So I assume this machine was originally NQS-L. If I wanted to put wider stereo heads on and did not use the pilot tone/timecode function would it work without any circuitry changes as an NQS-LSP would?

Thanks

MarkC

 

You could do that, if you could get the non-pilot heads. I am not certain if you need any electrical adjustments with he new heads (I would imagine not); the actual replacement of the heads is quite easy. Of course you need to make a complete readjustment of the heads, but that is what service manuals are for. I know a place that have a recording head on stock, but I don´t know the price of it...

 

I remember that you have the Harvey modded IV-S... I would really love to have such a machine, so personally I think it would be a shame to cripple the TC capability to get a marginally larger S/N ratio. But then again, I am just in it for the machines, not to really use them for recording.

11 hours ago, Lermontov said:

Thank you for fast response. I made some test recordings and when replaying with pilot playback chosen modulometer’s needle moves very little. Also I have some tapes recorder with 50Hz pulse sync and again modulometer reacts in the same manner. It oscillate around % mark on the meter.

 

I just checked with a couple of my 4.2 recorders (I know that at least one of them has problems with the pilot system...), and the pilot indicator should remain on when going into record mode. 

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On 10/30/2017 at 4:05 AM, Lermontov said:

 I have an XTAL plug in pilot socket.

 

I assume you mean that you are using the jumper plug on the Pilot-in tuchel connector. The crystal sync signal is routed from the crystal circuit board to the pilot record head through pins in the Pilot-in connector. This is an elegant way to activate the crystal function by plugging in the jumper or deactivating it be removing the jumper.

 

your copy seems to indicate that you are doing all this appropriately but it’s worth asking to be sure. 

 

David

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Jumper plug. I forgot how it’s called. Yes I have screwed this plug in Pilot tuchel socket. I thought that maybe this plug is defective and replaced it with 3 spare ones I have. I even put paper clip instead. Still no result. Guess there is some problem in the circuit.

ECC1757A-1F97-4384-AEC7-9D578203D87E.jpeg

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On 10/30/2017 at 10:58 AM, Lermontov said:

Thank you for fast response. I made some test recordings and when replaying with pilot playback chosen modulometer’s needle moves very little. Also I have some tapes recorder with 50Hz pulse sync and again modulometer reacts in the same manner. It oscillate around % mark on the meter.

 

 I have just checked up on the pilot system in the 4.2, and I have a couple of comments (but not an answer as such on why the pilot indicator turns off during record):

 

Your 4.2 has three options installed:

1) The QGX-50 crystal generator

2) The QFM-50 frequency meter option. It is that circuit that measures the frequency of the incoming og played back pilot signal. If the needle of the modulometer is stationary in the middle at 0% (when in the Frequency setting), the pilot frequency is exactly 50 Hz. If you go to playback, the pilot frequency is compared to the reference frequency. A difference between these two will result in the meter needle oscillation.

3) The QSLI synchroniser. This circuit will compare the reference frequency with the pilot signal. And here is a catch: If you select Playback without speaker on, the QSLI is not active, and the needle will oscillate, indicating that the speed is not spot on according to the pilot signal. When you go to Playback with speaker on, the QSLI will be engaged, and the meter should remain stationary, indicating that the QSLI has succeeded in regulating the speed to compensate for the pilot frequency difference. So in theory when playing back your old recordings, the needle will oscillate in Playback with no speaker and be steady when playing back with speaker on.

 

I hope hat it clarifies the workings of the system a bit; I will ponder over the service manual when I get the time and try to figure out why the pilot indicator goes off during record. It might not be a fault...

 

 

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Thank you very much Dela for so many informations! It did clarify the whole aspect of circuits installed in my 4.2.

One thing came to my mind. I’m using third party modern 18v PSU and I don’t have any fresh batteries at the moment.

Maybe I don’t provide sufficient power to the unit? 

 

 

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18V should be just fine. The Nagras are normally rated to work on 11-35V supply, and 18V is actually the voltage of a set of (new) batteries. 

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Hi all.

Just bought a Nagra III for a reasonable price, so I have two Nagra decks now !

However, it needs some work to be operational again...

The main issue is the top capstan bearing plate (the plastic part) is broken, half is missing, so the capstan will not run correctly at all.

I might try making up a replacement plate for this. Does anyone have a nice close up top view photo of this piece they could share with me ?

Also, the motor leads and the Modulometer leads have been disconnected, someone has been trying to fix it previously...

I will try & get the electronics/audio section working first, after fixing the damaged from corrosion battery contacts in the battery compartment.

Yes, it does have several issues !!  It would make a good parts unit if I really get stuck. At least it appears no other parts are missing.

Pity it has no serial number, someone has erased this from the front panel, scratched out !

Cheers, Chris.

 

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Finding a nice clean Nagra III is hard to do, there is always a lot wrong with them cosmetically.  I must have bought and sold 5 of them before finding two mint ones to keep. 
I only had one that didn’t work, what I find is most are all beat up but still work. Although, I don’t use them other than just proving everything works. I still check out just about every Nagra III that comes up for sale just to see if there are any differences in them.  I still see some nice ones now and then. 

 

 If you want I can post when I see a nice clean one up for sale or message you. I have three already and do not desire to own any others.  Unless you like the idea of a project. But what it sounds like because of the battery leakage and wires disconnected you have nothing but problems in front of you. The plastic piece is only the obvious.  When you do finally get it going the fact that the serial number is scratched out is a turnoff. 
Unless the outside is in really very good condition, it sounds like what you have is not worth fussing with. 
The first one I ever bought  and the only one I bought not working was for 50.00; the battery acid was so bad on the inside it reached into just about every part of the unit.  You can always sell it and start over.  I never had any problem selling a Nagra III even the 50.00 dollar one sold for 95.00.  I’m not sure how much you paid, but they can easily be had in working condition.  It's the cosmetic condition that's hard to find.
But all that being said I'm pretty fussy when it comes to a run of the mill Nagra III. Maybe you like fixing them up that's OK I understand that.  
I hope you'll find some answers here on Jwsound.  In fact, there are probably people on here that have the part you need.
Just know its easy to sell a Nagra III for parts and buy a real keeper.  That's what I did.

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Thanks Mr Bond for the comments.

I have made some progress, so there could be hope for it yet !

The battery contacts have cleaned up ok.

But more importantly, I have fixed the capstan bearing. The steel bushing had been pushed up and half out of place from the aluminium holding bracket on the top plate, this of course is what broke the plastic piece on top. I have pushed it back into place, and all seems good for the capstan now. Next to fix the disconnected wires & test the electronics....

Cheers, Chris.

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Chris:

 

If you need some info on the disconnected things, fortunately the schematics are included in the manual for the Nagra III:

 

http://lcweb2.loc.gov/master/mbrs/recording_preservation/manuals/Nagra III Instructions Manual.pdf

 

It is quite a while since I last looked at my Nagra III machines, but if you are not sure how to connect the motor and the meter, I can check up on it and send you some pictures of the cabling. The III can be a bit tricky to navigate in, because so much of it is enclosed in shielded modules...

 

As a collector I obviouslys like machines in good condition, but it is also fun to have a challenge once in a while. I have a water damaged 4.2 that I have spent a lot of time fixing just for the fun of it, and it is very satisfying to have fixed all the issues. It might not be mint condition, but still it has its history, and you get to know you Nagra really, really well by nursing it back to life.

 

 

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On 4/5/2015 at 2:31 AM, Glen Trew said:

 

Hi David. Enjoying this discussion. As you imply, comparing DAT to analog Nagra, as to which is best, is impossible to do because both have different strong and weak points. Here are a few additional not-insignificant points to consider:

 

First, the specs I mentioned are not only the specs I observed when aligning these machines, they are also the ones published in the Nagra manuals, and the way the machines arrived new from Nagra. These specs are the result of what was the excepted as being the best balance of signal-to-noise ratio, freq response, and harmonic distortion with low-print tape. It's easy to increase the signal to noise by recording hotter to the tape, but at the price of increase harmonic distortion. To get better than 70dB dynamic range, there must be compromises in one or more of these specs. Of course, the proprietary Nagra Master system of recording at 15ips with the same pre-emphasis standard of 7-1/2ips, increases the spec by a few dB, but, being non-standard, NM requires recording and playing back on another stereo Nagra that is, hopefully, properly calibrated. Another trick (but a good trick) was to use  the Dolby SR noise reduction scheme made possible on the Nagra 4 series with the Bryston module. However, this also required using properly calibrated Dolby SR hardware on both the recorder and playback device.

 

The -8dB reference you mentioned was the accepted equivalent for 0VU meters, and only gave 12dB of headroom (The Nagra maximum level to achieve published spec was "+4" on it's modulometer, which is 12dB above the -8 reference level. This spec was not decided because of the ability to saturate the tape, but done to counter the affects of tape hiss. Most Nagra operators never saturated the tape anyway, choosing instead to use the onboard limiter (not the best choice in my opinion). The 0VU reference level of -20dBfs on modern digital recorders came about not because it was necessary to avoid clipping, but because digital's low noise specs made it possible to have this much headroom, which also matched the headroom spec of most professional mixers. For example, if feeding a modern digital recorder with a Cooper mixer (pick one), aligning a -8 tone on the Cooper's peak meter at -20dBfs on the recorder, both the recorder and the mixer will reach maximum at about the same time (the mixer might have an additional dB or two).

 

The mention of DAT recorders not achieving their published spec due to preamps isn't valid, because the Nagra's specs were measured without the mic preamps.

 

I think the fact remains that if a modern 24bit digital recorder sounded like an analog Nagra, it would not be praised, but would be scoffed.

 

Now, if the digital recorder manufactures would follow the lead of nearly every Nagra since the early 60s by installing a speaker in the machine (Nagra still does this even with the tiny Nagra 7), it would be a great thing. Except for design considerations of the Nagra SN spy recorders, it doesn't make sense to have an audio recorder that requires another piece of equipment to hear what was recorded.

 

gt

Dear Mr Tr

 

On 4/5/2015 at 2:31 AM, Glen Trew said:

 

Hi David. Enjoying this discussion. As you imply, comparing DAT to analog Nagra, as to which is best, is impossible to do because both have different strong and weak points. Here are a few additional not-insignificant points to consider:

 

First, the specs I mentioned are not only the specs I observed when aligning these machines, they are also the ones published in the Nagra manuals, and the way the machines arrived new from Nagra. These specs are the result of what was the excepted as being the best balance of signal-to-noise ratio, freq response, and harmonic distortion with low-print tape. It's easy to increase the signal to noise by recording hotter to the tape, but at the price of increase harmonic distortion. To get better than 70dB dynamic range, there must be compromises in one or more of these specs. Of course, the proprietary Nagra Master system of recording at 15ips with the same pre-emphasis standard of 7-1/2ips, increases the spec by a few dB, but, being non-standard, NM requires recording and playing back on another stereo Nagra that is, hopefully, properly calibrated. Another trick (but a good trick) was to use  the Dolby SR noise reduction scheme made possible on the Nagra 4 series with the Bryston module. However, this also required using properly calibrated Dolby SR hardware on both the recorder and playback device.

 

The -8dB reference you mentioned was the accepted equivalent for 0VU meters, and only gave 12dB of headroom (The Nagra maximum level to achieve published spec was "+4" on it's modulometer, which is 12dB above the -8 reference level. This spec was not decided because of the ability to saturate the tape, but done to counter the affects of tape hiss. Most Nagra operators never saturated the tape anyway, choosing instead to use the onboard limiter (not the best choice in my opinion). The 0VU reference level of -20dBfs on modern digital recorders came about not because it was necessary to avoid clipping, but because digital's low noise specs made it possible to have this much headroom, which also matched the headroom spec of most professional mixers. For example, if feeding a modern digital recorder with a Cooper mixer (pick one), aligning a -8 tone on the Cooper's peak meter at -20dBfs on the recorder, both the recorder and the mixer will reach maximum at about the same time (the mixer might have an additional dB or two).

 

The mention of DAT recorders not achieving their published spec due to preamps isn't valid, because the Nagra's specs were measured without the mic preamps.

 

I think the fact remains that if a modern 24bit digital recorder sounded like an analog Nagra, it would not be praised, but would be scoffed.

 

Now, if the digital recorder manufactures would follow the lead of nearly every Nagra since the early 60s by installing a speaker in the machine (Nagra still does this even with the tiny Nagra 7), it would be a great thing. Except for design considerations of the Nagra SN spy recorders, it doesn't make sense to have an audio recorder that requires another piece of equipment to hear what was recorded.

 

gt

Dear Mr Trew,

 

Can you please enlighten me on how to calibrate a dolby NRS to an X4S. Do I need a special calibration tape? Is it necessary to have the qsnes? All the best for Christmas!

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On 8/6/2017 at 1:54 PM, Philip Perkins said:

This is actually the cart that a lot of soundies used in the '70s, and was available from rental houses.  Pinchy, heavy and awkward, it was why a lot of us started building our own.   I saw sound mixers shooting on the street in Hollywood with these in the '60s as well.

Wheeled-folding-cart-side.jpg

Oh how funny.  I had one of these, but by the time I gave it away, it had been heavily modified.  Those little wheels in the front were always a problem, even on the PSC cart.  I remember a mentor of mine, who I utility'd for on more than a few pictures, Ed Novick, reminding me "big wheels first."  I also remember my cart "getting away" and bumping into a curb.  Just like in upstate New York, Nagra Falls (sorry).

 

D.

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On 12/23/2017 at 6:34 AM, MarkC said:

Dear Mr Trew,

 

Can you please enlighten me on how to calibrate a dolby NRS to an X4S. Do I need a special calibration tape? Is it necessary to have the qsnes? All the best for Christmas!

I'm afraid I don't remember the process, and it depends on whether or not you have the 2-way system ("decoded" monitoring during record). There are manuals floating around you might search for. If I recall correctly, the IV-S is set up normally, and the Dolby setup is done on the Bryston units.

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On 12/26/2017 at 9:42 AM, Glen Trew said:

I'm afraid I don't remember the process, and it depends on whether or not you have the 2-way system ("decoded" monitoring during record). There are manuals floating around you might search for. If I recall correctly, the IV-S is set up normally, and the Dolby setup is done on the Bryston units.

That's what I recall too.   BTW this is how AC-powered Dolby NR rack units worked as well.

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Anybody want a rare Nagra QDAN?  Last time I looked at this it auction I thought I saw more pictures and I thought one picture confirming  it was serial number 91.  The seller for some reason took some pictures down. Maybe because it shows some defects I don’t know,  I was not paying much attention. Ask for more pictures and buy at your own risk, I do not know this seller.
I’m only sharing an ebay auction of a very rare, one of a kind,  Nixie tube product form Nagra.  Some fine polishing compound works wonders on a Nagra III type finish, although I was lucky and it was not needed on the one pictured below.
 
 
 
I already have mine,  
AlJINkz.jpg
 
 

 

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Dear JBond I love the neon light effect, Nagra is beautiful. 

 

Is it feasible that Nagra reduced the tape width on the Nagra IV-S to compensate for the increased S/N ratio made possible from NRS? Do the earlier IV-S recorders with 2.75mm heads have an NRS option? Just intrigued as always..

 

Not being a technician, I hope the "won't ever tells" unless asked will explain the NRS option. Was it better? Would it be better for quieter stringed instrument sounds?

 

Peace and a Brilliantly Happy New Year!

MarkC

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The pilot and non-pilot versions of the IV-S came out at the same time; they were just two variations of the same machine. So the non-pilot wide track IV-S also has the NRS option...

 

The only reason the track width was reduced, was to allow for a center track with the pilot information. It was important not to mix tapes recorded on wide- and narrow track recorders, so often non-pilot recorders were fitted with narrow track heads to avoid incompatibility. Sometimes non-pilot IV-S recorders are described/sold as very desirable and better for music recordings, but that only goes for wide track machines; if it has narrow track heads there are no difference.

 

As for the sound quality with NRS, I guess that a lot of factors play in, f.ex. the design of the specific noise reduction system and the calibration of the system/recorder. In theory the noise floor will be lower with a NRS, but it also adds a lot of circuitry to the signal path. So the resulting sound quality depends on the actual setup...

 

 

 

 

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Oh, seeing that picture of the Nagra power inputs.  Now I remember; Nagras were positive ground!!  I had forgotten.

 

Reminds me of a friend's quip that he thought Stefan Kudelski drove to work each day in reverse, using only his rear view mirror as a reference.

 

D.

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2 hours ago, tourtelot said:

Oh, seeing that picture of the Nagra power inputs.  Now I remember; Nagras were positive ground!!  I had forgotten.

 

Reminds me of a friend's quip that he thought Stefan Kudelski drove to work each day in reverse, using only his rear view mirror as a reference.

 

D.

Had to have been in an early 50's British car with positive ground electrical system.

LEF

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