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Nagra IV-S question (time code)


rstl99

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Hi all,

I recently purchased a Nagra IV-S from Pro-Sound, which possibly belonged to someone frequenting this forum (I was told it came from a sound mixer working in Hollywood). 

 

Anyway, my interest is in stereo music recording, so I'm thrilled to have this IV-S to play with.  This IV-S a time-code version, which I'm not familiar with.  Since I don't need to sync with anything the timecode circuitry if of no use to me.  However, I note a small toggle-switch just behind the speaker, inside, and wonder if someone could tell me if the position of that switch impacts in any way stereo audio recordings that I want to make with the IV-S.

 

I attach a picture in case this triggers your memory of the function of that switch.

 

Thanks for your help.

 

  --Robert

 

post-7331-0-74809500-1386802324_thumb.jp

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60hz pilot was for mono machines.  because the low frequency would bleed from the centre track,  13.5khz fm sync was developed. the record and playback heads were narrowed on the timecode version, to provide better separation and prevent timecode bleed,  which accounts for the lower signal to noise ratio on the timecode  machine,  compared to the regular stereo nagra. 

 

ao

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Thanks Crew, and ao.

I haven't done test recordings with it yet, but will keep the switch on FM sync as you suggest Crew.

 

I once owned a IV-S that had no center head, just record and playback heads.  I had read the IV-S had originally been designed for audiophiles can see why that 2 head model was the best possible configuration for stereo music recording (full use of the two halves of the tape without center portion reserved for pilot or time code). 

 

I've also owned another IV-S that didn't have timecode but did have a center head, which I assume is for recording an external pilot signal through the side connector?  Would the S/N ratio of that model have been slightly better than the time-code one I just acquired?

 

Cheers.

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The 60Hz pilot signal on the IV-S was frequency modulated at 7kHz, which is why it was referred to as "FM Pilot" instead of "Pilotone". This kept the 60Hz hum from bleeding into the audio tracks.

 

The timecode signal of the Nagra-issued timecode version of the IV-S (commonly but unofficially referred to as "Nagra IV-STC"),laid down the timecode linearly, without being frequency modulated. This is because the frequency of timecode was deemed sufficient to not bleed significantly onto the audio tracks. In truth, the timecode added perceptible noise, but it was mostly lost in the tape hiss. 

 

The early versions of the Nagra IV-STC did not have the option for recording without timecode. When this was scoffed at by those recording nonsyncronous music, Nagra accommodated by adding the option for disabling the timecode generator, thus reducing noise.

 

The Nagra pictured above appear to me to be a popular after-market timecode mod by Timecode Systems, affectionately known as the Harvey Mod. (If it is the Harvey Mod, there will be an LED display on top of the deck). It was a good, high-quality mod when installed properly. Unlike the Nagra version, the Harvey Mod allowed either FM Pilot or Timecode to be recorded on the center track. But if sync is not needed, you might as well disable the sync signal, whether it is FM Pilot or timecode.

 

Glen Trew

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I have about 15 boxes of 808 and or the re biased 908 scotch recording tape for that machine...  I need to look and see... I have been waiting to get it to someone who needs it... It's been a long time... still new and stored properly...If that someone is you, let me know....  PM me....  Make me a donation and pay for shipping and you can have it...

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That's not a Harvey mod board.  The Harvey install replaced the stock Nagra speaker (this one has the orig one) with a smaller speaker set back into the case, to accomodate the Harvey control panel on the right side where the speaker was.  A Harvey mod does not require opening the machine to switch from TC to FM Pilotone to no sync recorded at all--that was all avail on the rotary switches on that side-mounted panel.  This machine might have been a custom mod.

 

philp

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I can recall that when we got in Harvey mod 1/4" timecode tapes in the 1980s for telecine in post, those seemed to be more accurate than the original Nagra TC tapes for some reason. Eventually, Nagra worked it out and the timecode started having zero offset. 

 

Fred Ginsberg wrote a very thorough book on the Nagra IVSTC back in the 1990s. I believe it's still available for download at this link:

 

http://www.filmtvsound.com/index.php/user-manuals/category/14-nagra

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New to jwsound.

Just bought a nagra iv-s non-pilot ccir and looking for advice on service and parts. It was from belgium and i'm in canada. Any adjustments needed to the machine other than swapping power adapter fuses to run it on 120v ? I have a replacement 60hz speed strobe to swap with the installed 50hz one. Any suggestions on calibrating the speed and bias or who can do this would be welcome. I've been reading different posts about tape stock but still uncertain as to what i should buy.

Will be looking for a new modulometer as mine is a little mashed up with cracked glass but works. Also will be lurking for any reasonably priced QGB with hubs to expand the tape and playback options.

Good to have landed here. Seems a place i will learn from and hopefully can contribute as i can.

Chris

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The 60Hz pilot signal on the IV-S was frequency modulated at 7kHz, which is why it was referred to as "FM Pilot" instead of "Pilotone". This kept the 60Hz hum from bleeding into the audio tracks.

 

The timecode signal of the Nagra-issued timecode version of the IV-S (commonly but unofficially referred to as "Nagra IV-STC"),laid down the timecode linearly, without being frequency modulated. This is because the frequency of timecode was deemed sufficient to not bleed significantly onto the audio tracks. In truth, the timecode added perceptible noise, but it was mostly lost in the tape hiss. 

 

The early versions of the Nagra IV-STC did not have the option for recording without timecode. When this was scoffed at by those recording nonsyncronous music, Nagra accommodated by adding the option for disabling the timecode generator, thus reducing noise.

 

The Nagra pictured above appear to me to be a popular after-market timecode mod by Timecode Systems, affectionately known as the Harvey Mod. (If it is the Harvey Mod, there will be an LED display on top of the deck). It was a good, high-quality mod when installed properly. Unlike the Nagra version, the Harvey Mod allowed either FM Pilot or Timecode to be recorded on the center track. But if sync is not needed, you might as well disable the sync signal, whether it is FM Pilot or timecode.

 

Glen Trew

Thanks Glen for the detailed and always informative input.

As Phil noted, it's evidently not a Harvey Mod as there is no LED on top.

The side panel has the Nagra Time Code In/Out connector, so now I understand why a modification was deemed necessary to the stock circuitry, for the reasons you stated.

I'll have to take the cover plate off and have a look and see if I can figure out how to disable the sync signal, as you suggested, since I won't be needing it.

 

That's not a Harvey mod board.  The Harvey install replaced the stock Nagra speaker (this one has the orig one) with a smaller speaker set back into the case, to accomodate the Harvey control panel on the right side where the speaker was.  A Harvey mod does not require opening the machine to switch from TC to FM Pilotone to no sync recorded at all--that was all avail on the rotary switches on that side-mounted panel.  This machine might have been a custom mod.

 

philp

Good eye.  Rich at Pro-Sound NYC (where I bought the recorder) said he thought it was a Neil Stone modification for TC.

 

I can recall that when we got in Harvey mod 1/4" timecode tapes in the 1980s for telecine in post, those seemed to be more accurate than the original Nagra TC tapes for some reason. Eventually, Nagra worked it out and the timecode started having zero offset. 

 

Fred Ginsberg wrote a very thorough book on the Nagra IVSTC back in the 1990s. I believe it's still available for download at this link:

 

http://www.filmtvsound.com/index.php/user-manuals/category/14-nagra

Thanks for the link to the document.  I think I already have it from several years ago but will need to re-read and refresh myself with that aspect.

 

I attach a picture of the side panel showing the stock Nagra TC in/out connector, and a somewhat closeup of the inside, for interest.

 

Thanks again!post-7331-0-79712300-1386865792_thumb.jp

post-7331-0-59720700-1386865813_thumb.jp

 

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New to jwsound.

Just bought a nagra iv-s non-pilot ccir and looking for advice on service and parts. It was from belgium and i'm in canada. Any adjustments needed to the machine other than swapping power adapter fuses to run it on 120v ? I have a replacement 60hz speed strobe to swap with the installed 50hz one. Any suggestions on calibrating the speed and bias or who can do this would be welcome. I've been reading different posts about tape stock but still uncertain as to what i should buy.

Will be looking for a new modulometer as mine is a little mashed up with cracked glass but works. Also will be lurking for any reasonably priced QGB with hubs to expand the tape and playback options.

Good to have landed here. Seems a place i will learn from and hopefully can contribute as i can.

Chris

Welcome to the forum.  I'm also in Canada.  There's some great folks here with impressive knowledge of these venerable machines, so you will likely get some good insights into your situation.  From what I have read, the NAB Nagra IV-S's have arguably superior audio qualities to the CCIR (European) ones.  I've always steered away from CCIR Nagras because of uncertainty about running them in N-A, but others here will let you know if that's a problem or if there are solutions.

As far as the QGB goes, those attachments usually sell on ebay for more than a IV-S itself, so I don't know if "reasonably priced" ones can still be had.  For my recordings, a 7" reel is more than enough.

Service and parts?  Not too many places still work on these but I believe Trew Audio in Nashville still does (Glen can confirm).  Pro-Sound in NYC (from where I bought my IV-S) have service people and parts for them.  Others here will inform you better.

Good luck.

  --Robert

I have about 15 boxes of 808 and or the re biased 908 scotch recording tape for that machine...  I need to look and see... I have been waiting to get it to someone who needs it... It's been a long time... still new and stored properly...If that someone is you, let me know....  PM me....  Make me a donation and pay for shipping and you can have it...

Thanks, PM being sent!

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I believe the CCIR-EQ'd Nagras can be adjusted for NAB specs assuming you have the service manual, scopes, and test tapes. But that's a lot of assumptions. Nagra in Switzerland may be of assistance:

 

Audio Technology Switzerland SA, 
Chemin de L'Orio 30A, 
1032 Romanel, 
Switzerland.
 
Audio Technology Switzerland (USA) Inc.
450 W. Main Street 
Suite B-4
Gallatin, TN 37066
USA
(615) 451 4168
belt@nagrausa.com

 

I don't know how many spare parts they have on-hand, but I bet they may have manuals available as PDFs. I was always queasy about the QGB large reel adapters because it looked like such a Rube Goldberg deal, plus the rewind on portable Nagras was dodgy (to me). The AC-operated Nagra T, though, was in a class by itself and would play back, record, and rewind extremely well. I've seen those relatively inexpensive (under $1000) on eBay from time to time, which is well under their original $12,000 list price in the 1990s.

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I can recall that when we got in Harvey mod 1/4" timecode tapes in the 1980s for telecine in post, those seemed to be more accurate than the original Nagra TC tapes for some reason. Eventually, Nagra worked it out and the timecode started having zero offset. 

 

Fred Ginsberg wrote a very thorough book on the Nagra IVSTC back in the 1990s. I believe it's still available for download at this link:

 

http://www.filmtvsound.com/index.php/user-manuals/category/14-nagra

Not to mention "time code in the reel world" written by I think manfred klemme and Jim Tannenbaum wrote.

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That's not a Harvey mod board.  The Harvey install replaced the stock Nagra speaker (this one has the orig one) with a smaller speaker set back into the case, to accomodate the Harvey control panel on the right side where the speaker was.  A Harvey mod does not require opening the machine to switch from TC to FM Pilotone to no sync recorded at all--that was all avail on the rotary switches on that side-mounted panel.  This machine might have been a custom mod.

 

philp

Yes, Philip, after giving it more than a quick glance it's clear that it's not a Harvey Mod. The side panel is clearly a standard Nagra timecode IV-S panel, but switching between FM Pilot and timecode required a board change. Maybe it's a timecode machine with the FM Pilot board installed?

 

gt

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I believe the CCIR-EQ'd Nagras can be adjusted for NAB specs assuming you have the service manual, scopes, and test tapes. But that's a lot of assumptions. Nagra in Switzerland may be of assistance:

Audio Technology Switzerland SA,

Chemin de L'Orio 30A,

1032 Romanel,

Switzerland.

Audio Technology Switzerland (USA) Inc.

450 W. Main Street

Suite B-4

Gallatin, TN 37066

USA

(615) 451 4168

belt@nagrausa.com

I don't know how many spare parts they have on-hand, but I bet they may have manuals available as PDFs. I was always queasy about the QGB large reel adapters because it looked like such a Rube Goldberg deal, plus the rewind on portable Nagras was dodgy (to me). The AC-operated Nagra T, though, was in a class by itself and would play back, record, and rewind extremely well. I've seen those relatively inexpensive (under $1000) on eBay from time to time, which is well under their original $12,000 list price in the 1990s.

Thanks Marc!

Good to know.

I found the owners manual online but still wondering about what needs to be switched to run properly in NAmerica other than power unit fuses. If i record and playback my own recordings, i can keep ccir so long as i learn what tape the machine was last biased to right?

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I found the owners manual online but still wondering about what needs to be switched to run properly in NAmerica other than power unit fuses. If i record and playback my own recordings, i can keep ccir so long as i learn what tape the machine was last biased to right?

 

The only new 1/4" tape stock I know of today is RMGI, available here:

 

http://www.rmgi-usa.com/

 

How that would be biased is a good question. You'd really need the manuals, test signals, and scopes to find out for sure. And don't forget head alignment.

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I've never seen a Neil Stone IV_S mod, so that's a good guess maybe.  (The ones I saw were the 4.2 mods).  That is the stock Nagra lemo TCi/o, as far as I can recall.

 

philp

 

The Neil Stone Mod used the Denecke ST-1 (sync stripper) along with a Denecke SB-2 or GR-1. I don't see the ST-1 board in the picture, so I don't think it it is Neil's mod. ??

 

-- Charlie

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Well, it seems the modification of my recently acquired IV-S is proving intriguing, as to who may have done what kind of mod on it, so I removed the cover in case it reveals more clues.  Looks like a bit of a kludge to me...  Oh well, I assume it did the trick as the recorder belonged to a west coast sound man who has a lot of feature films to his credit!

 

post-7331-0-08877700-1386988922_thumb.jp

 

post-7331-0-07734400-1386988939_thumb.jp

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my guess is that perhaps the owner had both TC and FM Pilot boards available to swap between..

That sounds plausible.  If the lower board (the one marked "FM") would be the one swapped with a TC board, I'd have to see if the red yellow and white wires soldered onto it are hard-wired, or easily disconnected somewhere inside to accommodate the other board.  If not, I gather this wouldn't allow a spontaneous swap in the field, as some de-soldering would be required.  Anyway, it's a moot point for me, since I won't be using either FM or TC.  At some point, I may want to find out how to disable either, to just have audio recorded onto tape.

Maybe the previous owner will stumble on this post and clarify the mods that were done to accommodate his needs...

Thanks.

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Thanks Marc!

Good to know.

I found the owners manual online but still wondering about what needs to be switched to run properly in NAmerica other than power unit fuses. If i record and playback my own recordings, i can keep ccir so long as i learn what tape the machine was last biased to right?

Although you've sort of "hijacked" my thread  ;D  I thought I would direct you to this good description of the IV-S, which offers the following on the NAB vs CCIR for potential buyers of used Nagras:

 

"When seeking out a good used sample of a Nagra IV, one must be aware that versions made for the US market are obviously adapted for 60Hz mains as well as having the necessary equalisation conforming to NAB standards. The NAB equalisation is not really a problem, unless you want to play back tapes that have been recorded using European CCIR equalisation. Conversion of a machine designed for 60Hz to one that is to be used on a 50Hz mains, requires modification that can only be done by the local Nagra distributor."

 

From: http://www.adventuresinhifiaudio.com/22/07/2011/the-nagra-iv-s-two-track-magic-in-a-portable-tape-machine/

 

Hope this helps you.  I am not certain just what modifications "by local Nagra distributor" would consist of.  Perhaps if you contact one of the few shops still servicing Nagras they could let you know.  Hope you find a way.  Cheers.

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[snip]

Thanks.

  At some point, I may want to find out how to disable either, to just have audio recorded onto tape.

 

Maybe I'm missing something here, but I've been wondering why you don't just remove the jumper plug from the external pilot tuchel connector. Actually, looking at the photo supplied, the pilot jumper doesn't appear to be present anyway.

The pilot and/or TC signal passed through that 4-pin connector. Unless the signal were jumped from (if memory serves) the Xtal pin to the Grnd, the signal would not carry through to the sync head. Removing it would take the sync circuit out of the path completely.

 

Alternatively, if one doesn't have the screw-on jumper plug and wanted to use sync recording. one could just bend and cut a paper clip to a U-shape and use it with a piece of tape to hold it in place.

 

David

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