This is the Spot Tape (Cart Machine) Section of
The Broadcast Archive

Maintained by:
Barry Mishkind - The Eclectic Engineer
Last Update 10/16/22

Once upon a time, all commercials and music were broadcast live ... except when talent got "mic fright."

As records became used more and more in broadcast operations, many of the network programs were delayed. Commercials, and later, jingles were also "cut" into "electrical transcriptions," and as many as six turntables might be found in a control room. Spot breaks with a lot of short items were quite a busy time for engineers and disk jockeys.

Clay Freinwald notes that long ago Viking had a Model 35 deck used in businesses to play background music, playing large carts running at slow speeds. Some of the early manufacturers adapted the Model 35 to be used in broadcast operations. "I don't know the history of the 36, but I suspect that someone wanted the 35's to be remote started (other than turn on the capstan motor, as some did).

"Sierra (who ever they were, in California if I recall) adapted the 36 to broadcast use using the Viking Reel-to-Reel record amp and I had a cart machine in the station I was working at in the fall of 1961..

"An early player was Spotmaster and they put the 36 to work."


Tape machines

My sincere thanks to Alan Alsobrook, Park Seward, Tom Spencer, Lane Lindstrom, Larry Lamoray, Douglas Pritchett, Kim Sacks, Glen Kipple, and many others for sharing their pictures.

Click on pictures for larger view.

Please note the names above. They are some of the kind folks who shared pictures. More pictures are welcome - to show more about these key pieces of gear which made radio in the 60's-90's much more vibrant and exciting. Can you share any pix?

Pictures of various tape cartridge are shown below.



Louis G. MacKenzie developed his "repeater" in 1955. Using a silver coated tag applied to an endless tape loop (to provide a "cueing" function, the single and "five pack" machines could provide instant starting of desired spots. The tape cartridges were square metal boxes, with the tape loop hanging out.

The MacKenzie repeater was used extensively in places as diverse as radio stations, television and movie studios, and Disneyland. The multi-deck units were very popular for use to insert "sweeteners" in television and movie productions - added laugh tracks, for example, or audience applause, etc. Perhaps the biggest drawback for broadcast was that the tape loop was exposed outside the cartridge, making it easy to damage.


MacKenzie Repeater 500


MacKenzie Repeater APR-20

MacKenzie ProFx repeater

MacKenzie Cart (The box is metal, with an endless loop inside, but hanging outside.)
ATC (Automatic Tape Control)

Ted Bailey (then CE of WJBC) and staff engineer Jack  Jenkins developed the ATC (Automatic Tape Control) machine based on a transport from Moulic (SMC). A joint patent was granted to Bailey, Jenkins and Nolte (station manager of WJBC) as inventors. The cart machine was offered first to Gates, however Parker declined because he had the ST-101 in development., 

Collins Radio got wind of the machine, so when Gates Radio turned them down, Bailey and Jenkins took their design to Collins Radio and immediately made a deal to market the P-150/190 unit. ATC was formed in Bloomington, IL to manufacture the machines. Collins seemed to have set fairly high prices and sold fewer units than ATC desired, leading to a parting of the ways, giving Gates a second opportunity at Jenkins' design.




Gates Radio

When Bailey and Jenkins approached Gates with their design, Gates Radio was already developing the ST-101. The ST-101 found its way into many stations, but it was not practical to run more than one spot at a time. Eventually, Gates changed and built machines that could utilize individual cartridges.

Eventually moving their products from Collins to Gates, Jenkins designed the Criterion series. The company was purchased by Gates and became the Automatic Tape Control Division. (Harris was afraid Automatic Time Control would charge trademark infringement.) Mo Franklin, Andy Rector, Jack Jenkins and others resigned and departed the Gates Radio Division when it became apparent that Harris would not support a continuation of the ATC quality tradition. 

This led to ITC. 

ST-101 - 1960 - $995
This unit featured a 13-inch-wide tape belt and moveable head.  It could run 101 different tracks, but only one at a time. 



CartriTape II

Criterion II

Criterion 80

Criterion Compact

Criterion Compact III



Criterion 90

from Radio Estancia, Sao Lourenco, Brazil

Criterion 90-3

Broadcast Electronics

In 19xx, Broadcast Electronics was formed to manufacture the Spotmaster brand. The original machines used a Viking 36 deck. Quite a few announcers who got their start in the 1960s remember the distinctive lever, used to engage the cartridge. 


Spotmaster 400A recorder 


Spotmaster 405 reproducer - The first of the famous ones with the "hand crank" to bring the pressure roller up for use. The case on this one is made of wood!

Spotmaster 500A recorder


Spotmaster 500B  recorder

1963 - $695 - to switch from record to play you had to rotate the knob on the lower right.


Spotmaster 505B playback 

1963 - $545

Spotmaster 500C  recorder

The record switch was replaced with a button.

Spotmaster 500D  recorder

Spotmaster 500AR Rack mount

Spotmaster 10-70






5500C five stack

Approximately $5000 in 1988 

Ten Spot

PhaseTrak 90 RPS featured a built-in phase meter and correction, and a splice finder
    Delay unit - Many stations used this model to foster local talk shows, especially the telephone talk programs. This and similar machines eventually gave way to digital (bit brigade) machines. 


Rockville, MD

TC-1000 - playback   Sold for $400

600-P - reproducer

700-RP - recorder

700-RP - recorder

700-RP - Stereo recorder

700-P - reproducer
   X-700RP - recorder

X-700P - reproducer


This is another company that started with the Viking deck and built a solid broadcast cart machine, then branched into other products.


A Viking deck with foil sensors.



Sparta 600P Rack Mount. A record amp was available.

Century Series

It is reported that RCA's early machines used a Viking 38 deck, modified for broadcast use.


RCA Four Stack, with automation switching

Glen Kippel says: "There is a rotary switch on the front (minus the knob) marked MANUAL-REMOTE-SEQUENTIAL-AUTOMATION. I assume that in the REMOTE position, the carts could be started by buttons on or near the mix console. SEQUENTIAL may mean that it will fire the carts 1-2-3-4 in sequence. AUTOMATION [probably] means that the carts could be controlled by some sort of automation system. MANUAL probably means the bttons on the front panel are used. It is a HEAVY dude -- I would guess somewhere in the vicinity of 100 pounds, or more.



ITC - International Tapetronics Control

Before his resignation at Harris, Jenkins was working on a new tape deck design. Franklin, Rector, Jenkins (as President, Sales Manager and CE respectively) and several backers then formed a new company south of Bloomington called ITC (International Tapetronics Control). The ITC designs were all pure Jenkins. The RP and SP machines were known as workhorses that truly merited the label "Premium Series." In the late 1970s, the "99" series was born, a combination recorder, player, eraser and splice locator. ITC was purchased by 3M in 19xx. 3M sold it to Don Carle and Al Taylor in 1990.  The company did not do well and went out of business in the 90s.

The RP/SP series were among the most popular of all cart machines.


SP - 1970 - The workhorse for thousands of stations.

RP - 1970

3D - a nice machine in many ways, but the lack of a middle bearing made the center deck subject to more wow and flutter than the top or bottom decks. A bit of a maintenance headache at stations where there was only one unit in the control room.

99 (There was an "A" and a "B")

PD-II - a real budget level machine for stations that could not afford the RP and SP.  Designed by Paul Dillow, it was the second attempt by ITC to build a low cost machine, hence PD-II

Delta - 1983

Delta 3 - Unlike the 3D, each deck could be removed without affecting the other two.

Omega - another cheap effort
Series 1 - This was a 3M driven machine.  

Series 2 - Built after 3M sold the machine, it was never a big success.  

1K - 1977 - a concept product. Only one was built. It lived as aa automated telephone library system at the University of Wisconsin, Madison for about 10 years. Technology moved too fast - and this Z-80 based machine was obsolete almost as soon as it was designed..

PR&E - Pacific Recorders & Engineering

In the late 1970s, the folks at Pacific Recorders designed the Tomcat. Using "MaxTrax" heads, unmovable precision heads with extra width on the program channels to improve S/N and headroom, many stations found the S/N and stereo integrity of the Tomcat's fixed heads to be superior.

Carts recorded on the Tomcat were incompatible with any other machine. However, the Tomcat quickly had a reputation for solid operation with stable stereo reproduction. 

Still, the Tomcat was quite expensive. So in 1986, PRE delivered the Micromax, based on the British Sonifex machine. The Micromax was a very quiet, cool running (the recorder only used 15 Watts) machine that many stations found to be just what they wanted. The belt and flywheel kept wow and flutter way down.

Tomcat - 1980 Recorder

Tomcat - 1980 Reproducer (Three in a rack mount)
Micromax - 1986 - Recorder - Electronics by Jim Tonne.

Micromax - 1986 - Reproducer


Ampro was sold to Scully in 197x. In November 1983, Ampro/Scully was sold to TTC


2500 Series

3500 Series

4500 Series
    8300 Series



CTM-10 Series  CTM-10/CTM-10M/CTM-10S/CTM-10R

CTM-10 Series reproducer



Series 100

Series 200


Audi-Cord was founded by Carl Martin who was another former ATC engineer.


A Series A10

E Series E10/E11/E15/E16/E20/E21/E25/E26/E50/E51/E55/E56

S Series S11/S16/S21/S26, TDS1/TDS6
  DL Series DL-P/DL-R/DL-D


In 19xx Mike Sirkis began to build a new line of machines for Fidelipac, among others. His Dynamax series, for example, used photocells to identify different carts, allowing the system to react to different emulsions, recording levels, or even contact closures. Unfortunately, his association with Fidelipac did not last. The CTR-90 was designed by others.


Dynamax CTR-10

Dynamax CTR-30 - a three stack

Dynamax CTR-90 

Dynamax CTR-100 - recorder

Dynamax CTR-100 - reproducer


In the early 1970s, Don Kalmokoff and engineers at CKNW invented the Aristocart whwen the CFMI automation system had problems with stereo music on the Fidelipac carts. The company lasted until the mid-1990s, with Kalmonkoff retiring in the early 90s. 



A British company, Sonifex machines have had an impact on American machines, but have not sold well here.


microHS - 1979
microHX - 19






   1000 Series


A curious cart machine. Designed by Ry Smith, this one was the only cartridge machine able to reverse/rewind. KRS Magnetics was in Los Altos, CA. Smith even turned the idea into a reversible 8-track machine (the REV8) ... in 1979.

 KRS STACT - A single record/play

IGM - International Good Music


InstaCart 48 slots! (48 heads and rollers to clean!!!)

Primarily used in automation systems, it was also employed by some stations with "aggressive formats."



The Moulic family (Edison and sons Robert and William Jr. started Moulic Specialities in 1945, renaming Sono-Mag Corp  (SMC) in 1968.

MaCarTa = Magnetic Cartride Tape - almost exclusively used in automation systems (see below).
  DP-1 Digital Programmer

SMC Controller

KIOC - Vidor, TX - 1982 - Courtesy: Michael Minn

  250 - Carousel - 1962 - some 10,000 sold.

350 - Carousel -
590/592 Cart Record/Play




Automation Systems.

IGM, SMC, Gates, Harris, and others had automation systems that used cart machines in various forms. 

Carousels, Gates 55, AudioFile, and other names were familiar to users of these products.  This page can be found here.


The Cartridges

What is inside:

Plastic carts were invented for the audio tape player, usually a four-track machine for automobile installations. Several manufacturers adapted them to broadcast use.
Fidelipac and Audiopak developed this into a broadcast standard, which lasted for many years.
As more and more stations began broadcasting stereo music on carts, the manufacturers 
developed machines and carts to reduce stereo phase errors. 
  • Fidelipac developed a cart that used a longer tape path, so the tape was oriented vertically sooner. 
  • ITC developed the "Scotchcart," which used no pads, but a long tape path and 
    internal pressure to maintain constant tape speed and phase.
  • With the more sophisticated market, BE introduced features like automatic stereo phase correction.


Cartridges were made in several sizes, including the A or AA, which was standard for 
shorter carts, B, and C sizes, which were used for longer purposes, such as the
recording of each minute for time announce systems.

Click on picture for larger view  

It used a metal case and
silvered tape for cueing

Marathon carts were known for their rounded end. Pictured here are two test carts.


Early 1970s, this cart had a guide post at the back end to give tape time for stabilization as it ran.


300 - Standard cart "A" size

300 - Standard cart "B" size

300 - Standard cart "C" size
      350 - Stereo version with an adjustable corner piece allowed the cart to be "tuned" for best stereo reproduction. 
    Mastercart - Red - A longer tape path was used to "settle" the tape before it reached the heads, with the goal of even better stereo performance.
        Mastercart II - 
  Fidelipac used other formulations to try to improve the S/N ratio, including one with a High Energy/Cobalt emotion.
Audiopak Originally a division of Capitol Records

Scotchcart - brown. When 3M bought ITC, they designed their own cartridges - with optimal stereo reproduction as the goal. The Scotchcart had no turntable or pressure pads. An arm was used to keep the tape tension constant.
    Scotchcart II -  black.




And when the tape goes bad?