some notes: Contrary to what the narrator says, the Nagra SN (miniature) series wasn't originally devised for surveillance; the first version was full-track, ran at 3.75 ips and supported crystal sync, and was used for film sound as an alternative to a "wireless mike" (pocket transmitter). The 15/16 ips, half-track surveillance model ("SN-S") came later. There was also an in-between model "SN-G" with the same half-track heads as the SN-S, but set up mainly for the 1-7/8 ips recording speed.
In case it's not clear from the video, the SN recorders used cassette tape stock wound onto little reels.
The two-needle modulometer on the IV-S recorder had a nifty setting in which the green needle would display the peak value of the higher of the two channels, while the red needle would give a frequency-weighted reading of the difference between the channels. That corresponded directly to the horizontal and vertical modulation that would be cut into a stereo record groove. This made it obvious if you had a mike or cable wired "out of phase" (with inverse signal polarity). It would also let you know in a hurry if your miking wasn't suitable for eventually cutting a stereo LP from your tape, since excessive vertical modulation could cause phono cartridges to mistrack or even skip. Recordings that made the red needle move very much in this mode tended to be incompatible with mono playback, and since I did a lot of recording for FM radio stations and NPR, etc., where mono compatibility was considered very important, I watched it carefully.
The reason the narrator couldn't get the IV-S to go into fast forward mode has nothing to do with the battery. He apparently didn't realize that he needed to turn the operating lever on the front of the machine one more click, to the "playback with speaker" position, for fast-forward to work.
The IV-S machines had a socket on the left side of the machine where you could connect noise reduction circuitry such as Dolby "A". That way you could use the microphone powering and the excellent, low-noise preamps of the recorder--then feed the signal out to the noise reduction circuitry at line level and from there, back in to the recorder where it would go onto the tape. -- The IV-series machines also had a nice set of optional low-cut filters for music and speech in good rooms as well as filters for rooms with too much "room gain" at low frequencies, and one extreme "roll off" setting beyond even that, for truly crappy rooms.
The IV-series machines could take 7" reels as the man said, but this didn't require a special lid (though one was available for that purpose)--you could also remove the existing lid entirely and use 7" reels that way. 10.5" reels could be used via an outboard accessory ("QGB") which had two motors and a tension servo system in it. I recorded many, many concerts on that type of setup from about 1973 through about 1981, when portable digital recording equipment such as the Sony PCM-F1 became available. But I still have my IV-SD and SN-G recorders right here for playing back the tapes I made on them.
--best regards
Topic: Nice YouTube video - Nagra III, IV, IV-s, IS and SN reel to reels (Read 2142 times)