AUDIOCLINIC (Feb. 1995)

Archiving Radio Programs

Q. I have several hundred 7-inch reels of old-time radio programs. To reduce the cost of recording media, I recorded one of these monophonic programs on each of the tape's two channels. I recorded at 3 3/4 ips because 1 7/8 ips would not have been practical for trading shows with other collectors. I am concerned about finding a more lasting medium on which to archive these programs.

It would also be nice if I could do all this without going broke. Taking into consideration both cost and recording density, what medium is best? I have considered DAT, MiniDisc, and even 8-mm videocassettes.

Am I missing some other possibility? I would have to buy new equipment for DAT or MD, but I already have an 8-mm deck. My concern is that 8 mm is still tape and subject to a limited life. MiniDiscs are optically recorded; this would seem to offer the hope of long life.

With any of these formats, can I still continue using the left and right channels to record separate programs?

-Ronald Riemer, Phoenix, Ariz.

A. I'm also thinking of copying my many reels of old-time radio shows to some other medium. However, I know of no machine in any of the formats which you mentioned that can record each channel separately. That will be no problem when copying your existing tapes, which already have two simultaneous programs running together. When you copy new material, you may have to sacrifice the economy of your current double-tracking sys tem, unless you can simultaneously feed two mono programs into the recorder at once, using one channel for each.

As to long life, all the systems you name (and one more contender, which I'll get to later) use tape, except for MiniDisc. Its magneto-optical recording system, while possibly not offering the life expectancy predicted for CD, may well be the safest of the lot for archival recording.

To determine recording density, we must see how the various formats stack up. If you record at 3 3/4 ips in quarter-track mono and use 1-mil tape, you will get six hours on each reel. That would double if you could simply recopy the programs onto reels at 1 7/8 ips. (Whatever you do, though, don't consider using half-mil tape.) You can use conventional C-90 cassettes.

If you can arrange to simultaneously record two programs, one on each channel, you will really get 180 minutes of recording on such a tape. However, I am not convinced of the really long-term stability of most audio cassettes. (Good open-reel tape holds up quite well.) I have used Maxell UD tape and to date have not had problems with it. And the cost is low: 90-minute cassettes usually sell for less than $3 each.

With MiniDisc (MD), you can record 74 minutes or so-but again, if you can record two separate programs at one time, you'll double that. The resulting 148 minutes isn't bad, but even so, if you're recording half-hour programs, you'll only be able to get two of them on each track. Later this year, there should be MD recorders that will be able to make 148-minute mono recordings as well as 74-minute stereo ones. Aside from the convenience for your purpose, this would let you get five, instead of four, programs per disc, allowing 29.6 minutes for each program. However, MD is much more expensive than cassettes about $18 for a 74-minute disc.

At standard speed, DAT cassettes offer maximum stereo recording time of 120 minutes; most DAT recorders also have a long-play mode that gets double this recording time. When you record separate programs on each channel, you then have up to eight hours per DAT cassette. It is very, very unlikely that any of your shows have upper frequencies above 10 kHz, so you shouldn't mind that the frequency response at this speed is flat to only about 14.5 kHz. The Minidisc can rival that, but there are some problems with transients on this medium. Discount mail-order houses sell R-120 DAT tapes for about $10 each. I therefore think that this is a very competitive price compared to the others.

We can throw in another system, VHS Hi-Fi. In the six-hour mode, when recording separate programs, it can actually hold up to 12 hours of programming. I have found some good-quality VHS tapes at less than $3 each, so this system can prove economically practical. I have had some problems here and there with edge damage, which can cause flutter and distortion at times. This can sometimes be corrected if the machine has a manual tracking control; I have yet to see how well these problems can be compensated for when using an automatic tracking system. So, I am not truly sure if this medium is really good for archival purposes, although I use it that way.

Last, we have the 8-mm video format. Just how well this stacks up depends on the machine. At a minimum, it will let you record up to two hours per reel, doubled if you use your recording scheme. Some machines can also record in an all-audio mode, like VHS Hi-Fi. Some machines let you record six pairs of stereo channels, each of which can record up to two hours per tape, for a total of 12 hours--24, if you record as you do now. Still other 8-mm machines have six stereo pairs that can each hold up to four hours per channel, which will double to eight hours when recording in simultaneous mono. This is an astounding 48 hours of taping on a little cassette! That's impressive! I can't say for sure what the price for each tape may be, but you can bet that if you figure a price per hour, this 8-mm system will beat the pants off any other system.

I do not know for sure what the life span of these tapes is, but I suspect that it may be better than standard VHS Hi-Fi tapes. I also do not know the frequency response on a machine of this type. Unfortunately, it is very hard to find machines of this type as new items. Kodak used to make a machine that provided the six stereo pairs at two hours per pass. Sony, with its SV-3000, could record our 48 hours per reel. These are no longer made. If you want to find any of these machines, about all I can suggest is that you place an ad in our Classified section. I have been told, too, that Audiomart (Rte. 3, Box 692, Crewe, Va. 23930) can sometimes come up with odds and ends like this.

Before we get completely carried away, we are forgetting that the more information packed onto a small space, the harder it will be to retrieve. You will have to maintain very careful records of counter settings, for both left and right channels, versus program name. If we are talking 8-mm, we must keep track of all this plus the particular pair of channels on which to look for the program. This is a formidable task of record-keeping. It can be done, but be prepared to spend long hours compiling your data base, and you had better make good backups of the information.

The DAT and MD formats are the only ones I know of that can solve the retrieval problem to any extent. During the recording process, whenever you start recording or when both channels are silent, the recorder will set an index mark that the machine can readily find in playback. If you're recording in simultaneous mono, where the silences might occur in only one channel at a time, you can put an index mark on the tape or disc by pressing a but ton. The DAT system won't retrieve information as fast as one can search for information on a MiniDisc, but it is certainly fast enough for most applications.

Audio on Ice

Q. I have heard a great deal about power amplifiers getting hot, about the need to position amplifiers where ventilation would not be a problem, and about how manufacturers employ heat-sinks and fans to keep equipment operating at a safe tempera ture. I was wondering if dry ice could be used as a coolant. Would it damage equipment by lowering the temperature too much, or would the amplifier operate better than at room temperature?-Name withheld AI think that using dry ice to cool a power amplifier is an extreme approach; it should not be used. Chances are you would need a fan to blow over the ice in order to direct the cold air onto the heat-sinks. If you try using dry ice, be sure to protect your hands.

Amplifiers are designed to run warm, somewhat above ambient room tempera ture. Running the amp at really low temperatures could easily change the output stage's operating characteristics. This change would likely lower output and in crease distortion.

Recording in Your Car

Q. I have sought in vain to acquire a car cassette system that is capable of recording. If I can't buy one, is there a standard outlet on any car cassette system that will allow me to connect a portable recorder to it?

-Jay Wilfong, St. Petersburg, Fla.

A. I don't know of any current car stereo units that can record as well as play. Many car systems do have line-level outputs designed to drive external amplifiers, and a portable recorder could be connected to such an output. However, the signal level at these outputs depends on the volume-control setting. If you adjust your listening volume while you're recording, you'll also change the signal level going to the recorder-and if you turn the volume down, there may not be enough signal to drive your recorder to full modulation.

A skilled electronics technician could probably add output jacks that tap the signal before the volume control, and possibly even buffer the new outputs so turning your recorder on or off won't affect the signal you're listening to. But any recordings you make off the air while driving will be affected by interference, fading signals, and other problems common to car radio listening; these problems will become more annoying each time you listen to the tape.

There has always been some demand for car stereo units that record, and manufacturers have occasionally produced them.

However, the demand has never been enough for anyone to keep such a model in production very long.

Recording by Timer

Q. I was very disappointed that Audio's Annual Equipment Directory issue (October) fails to note whether analog cassette tape recorders have timer-controlled record/playback capabilities. I do lots of off-the-air recording, so, all else being equal, this is a deciding factor in my purchase of a deck.

I am concerned that manufacturers will eventually eliminate this feature.

-Ken Massey, Indianapolis, Ind.

A. Audio does not ask companies about timer recording because the available space must be used for features and specifications of widest interest. How ever, as long as there's substantial interest in a feature, manufacturers will continue to provide it. (Editor's Note: Timer recording would seem to be a more popular feature in Japan, where electronics stores usually carry suitable timers; such timers are comparatively rare in the U.S. However, since most cassette decks come from Japan, the feature seems likely to remain available. –I.B.)

I recently worked with a Technics DCC recorder; timer control was a well-implemented feature. Although your concern is analog decks, you should be heartened to see the feature appearing on new designs.

I have found that some machines permit timer control, even when it was not specifically intended. If you have an older deck with a wired remote control whose buttons stay down once they're depressed, plug the machine into your timer, set up for recording, and press the remote's play/record buttons. When the deck starts getting power from the timer, it should begin to record.

The old piano-key decks can also be used this way. However, leaving the idlers and capstan roller engaged while waiting for the timer to start can create flat spots on the idler, causing wow and flutter. It's best only to use this trick for short periods.

The pads or soft-touch buttons on decks with all-electronic control do not remain depressed. I once got around this difficulty by wedging the desired buttons so that they could not pop out. When powered, the deck immediately went into its record mode. This may not work with all machines, and problems might arise if the buttons are still jammed down when the tape comes to an end.

Headphones vs. Subwoofers

Q. My powered subwoofer is connected, as recommended, between my integrated amplifier's pre out and main in ports.

This puts the subwoofer's crossover in the path to the headphone outlet. Therefore, when I listen through headphones, I get no bass below perhaps 90 Hz, the subwoofer's crossover point. My attempt to bypass the subwoofer, using two four-pole double-throw switches, worked but gives me a lot of hum.

What else can I do?

-Robert A. Keeler, Grand Rapids, Mich.

A. You have already partially solved the problem. Actually, the switching can be done with just one four-pole double-throw switch. The switch and its associated tie points and/or connectors should be mounted in a metal project box. The metal will act as a shield.

To minimize the number of phono plugs, I suggest that all wiring to and from the box be "captive cables." In other words, do not mount any connectors on the box.

(You could, but I don't recommend it.) Cables will exit the box, and they should be marked as to where they are to be connected: Pre out, main in, crossover in, and crossover out (this last is for the satellites).

Of course, you duplicate these cables for the second channel. Be sure to run all grounds through, or you won't have a signal path; you will not be switching grounds. (Your use of the second switch suggests to me that you did just that.) If hum persists, you might try breaking the ground path for one channel.

Use two poles per channel (thus, the four-pole switch). We will consider each pole as a separate switch, for ease of discussion here, but we'll just talk about SW1 and SW2, for the left channel; you need simply to duplicate this wiring for the right channel.

The center terminal of SW1 is connected to the pre out cable. The center terminal of SW2 is connected to main in. Position A of SW1 is wired to position A of SW2. Position B of SW1 is wired to crossover in. Position B of SW2 is wired to crossover out. A 1-megohm, 1/4-watt resistor is wired be tween pre out and ground. A second such resistor is wired between crossover out and ground. (The resistors are used to remove the possibility of a transient click when the switch is moved from one position to the other.)

When the switch is moved to position A, the pre out is directly wired to main in.

This permits either full-range satellite or headphone listening. When the switch is moved to position B, pre out is wired to crossover in; main in is wired to crossover out. The subwoofer will then be placed in service.

(Audio magazine, JOSEPH GIOVANELLI, Feb. 1995)

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