Readers enjoyed Criss Onan’s article about the NAB cartridge and the machines that played them (“These Were the Carts of Our Lives”). They sent the following letters.
Cart memories
The cart and those machines started my career in radio technology over 50 years ago. I had the fortunate opportunity to spend hours with Jack Jenkins at International Tapetronics Corp. I believe he and Larry Cervon played the major parts in making NAB carts the mainstay of broadcasting for over a decade — from simple spot machines with less-than-spectacular audio, to machines and tapes that delivered reel-to-reel performance.
I remember the Fidelipac 300s with their pencil leads for lubrication. Other early carts included the Aristacart, whose engineer demanded removal of the center tape guide, and the Tapex, the cross-your-heart bra of carts. Then Capitol Magnetics and the A-2 cart.
Eventually Fidelipac and Audiopak/Capitol both came out with high-performance carts, the Fidelipac Mastercart and the Audiopak AA-4. The latter had superior tape and became a favorite for all cart formats. Then came the ScotchCart, a 3M product that was introduced with 3M’s purchase of ITC, and ITC’s introduction of the revolutionary Series 99A. Unfortunately the cart didn’t work well with the 99A.
The tape pack was outside of the bulk erase coil in the recorders; and there were problems with grounding the tape due to the fact that the ScotchCart had no pressure pads and the 99A had a ceramic capstan shaft; because ceramic doesn’t conduct electricity, a charge would build to the point where the tapes would bind.
All problems were solved with the 99B; ITC couldn’t make them fast enough. The 99B RPSE listed for $5,995 in 1981.
— John F. Schaab
Tower of carts
Criss your article was thoroughly enjoyable and certainly brought back plenty of memories. I would like to share my favorite from cart machine lore long ago.
I was working in a midsize-market AM/FM. The AM was live DJs, the FM was a Gates automation system playing easy listening music with six reel-to-reel music tape decks and a 55-stacker cart machine, plus one cart machine solely for station IDs.
The real beauty of the system was the 55-stacker. It was a mechanical marvel, comprising one cartridge playback deck that was moved up and down vertically by means of two large threaded screws to pick out the next commercial cartridge to be played. The motorized screws moved up and down on either side of the cart deck to position it in place to receive the cart from its resting shelf on the front of the machine.
In theory it was simple: Play the first cart at the top of the column when requested, eject it to the empty cart slot, drop the cart playback assembly one space and draw the new cart into the machine, and at the appointed time play it. Repeat the sequence until all 55 carts were played. Reload the machine with new spots and repeat.
The problem arose if the playback deck got ever so slightly out of alignment. It would either fail to draw the cart in, or would not eject it properly.
The rubber pucks that inserted and withdrew the carts, made by Gates, were robust. Problem was, even small misalignment of the player deck assembly would result in the pucks trying with all their might to seat the cartridge; when this failed to happen, it didn’t know when to give up. The carts would literally explode into flying pieces of plastic shrapnel. Run for cover!
The 55-stacker used a heavy-duty motor to drive the screw drives. Because of the high motor startup current, Gates had placed some high-wattage low ohm value surge start-up resistors in line with the AC voltage mains to the drive motor. Simple enough.
But one weekend, one of the surge resistors burnt out. The result was that the whole 55-cart machine was out of service till the electronic parts store opened on Monday. All commercial revenue would be lost.
Not so fast! Broadcasting engineers are pretty ingenious. When I reported for work the chief engineer described the problem and his solution. He determined that the heating coil in the engineering coffee pot was approximately the same resistance as the surge resistor. So he wired it in place of the defective resistor.
My assignment for the shift was to make sure there was water in the coffee pots so the resistor in the coffee pot didn’t burn out. I was on water detail all evening to ensure the pot never went dry. Oh what good times.
— Walt Konetsco, Retired Foreign Service Officer and Voice of America Field Engineer
The weight of history
Thanks so much for publishing Criss Onan’s terrific article on the history of the broadcast audio tape cartridge machine. What a fascinating story!
Reading it brought back a memory of how I obtained my first personally owned cart machines. In 1972, I worked as a design engineer at Gately Electronics, a pro audio manufacturer and Ampex distributor, in my hometown of Havertown, Pa. One day, one of our customers, Joel Fein, stopped out to pick up some Ampex audio mastering tape for his recording studio.
I helped Joel load the Ampex tape into the trunk of his 1960-something Chevy Impala, and I noticed that he had two RCA RT-7B cart machines nestled in each of the Chevy’s rear wheel wells. I asked him about the RT-7s and he told me that he was using them to give his Chevy “Better Winter-Time Traction,” as each one of those machines weighed close to 50 pounds!
Joel had taken the RT-7s as payment for studio time, and he offered them to me for helping to load his trunk. I still have them to this day, and they both work perfectly.
BTW, you can see one of Joel’s credits as a re-recording mixer on the restoration of Stanley Kubrick’s motion picture “Spartacus.”
— Steve Hemphill, Licensee, WA2XMN, Alpine, NJ.
MacKenzie and more
Thanks for your great reference on broadcast cart machines. I started repairing them in the 1970s when a few were donated to our local community radio station. We ran many PSAs, as you can imagine, and carts sure beat reading them live.
I have a collection of recording equipment including BE, Spotmaster and the top-of-the-line Pacific Tomcat, the pinnacle of cart technology. Many similar patents including Cole’s “uni-reel” and others flooded the industry, with many never getting out of the design phase.
How about a piece on the MacKenzie repeater, which found its way into many stations across the U.S. and Canada?
— Matt Laube, Vintage Tape/KC8HGQ, Williamsburg Ohio
Criss Onan replies: Thanks for the suggestion. I’ll see what documentation I can find. An increasing challenge is that many primary contacts have passed.
Several technologies attempted to replace the NAB tape cart for spots, including wide multitrack loop, magnetically-coated Mylar disk, cassette, DAT, floppy, 8MM and Bernoulli. However, MacKenzie seemed to be the most viable one.
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