Ampex ATR 124

• The ATR-124 was introduced by Ampex in 1979 as its most advanced 24-track machine, using 2-inch tape width. 

• According to sources, only around 50-70 units were ever made (some say 62) due to its very high price and niche market. 

• It is regarded by many in the pro-audio world as one of the finest sounding analog multitrack tape machines ever built. 

• Despite its quality, the machine’s high cost and the rise of digital recording led to limited commercial success; by 1983 Ampex exited the professional audio tape-recorder market.

• The ATR-124 uses a 2″ wide tape (standard for 24-track analog multitrack) along with large reels (studio size) and robust transport mechanics. 

• Tape motion: Controlled by capstan servo for speed/direction, and reel servo for tape tension and reel drive; no conventional pinch-roller mechanism is used in the usual consumer sense. The transport uses a capstan + servo design. 

• The machine supports multiple tape speeds (noted below) which allow flexibility for differing fidelity versus recording time trade-offs. 

• The machine is physically large, heavy, and required professional installation, cooling (forced-air ventilation) and maintenance due to its complexity. 

• Channels: Up to 24 tracks for audio recording/reproduction in the flagship model. 

• Selective Synchronization (Sel-Sync): Enables recording on one or more tracks while simultaneously monitoring other previously recorded tracks. This is critical for overdubbing in a multitrack studio. 

• Operational features include:
  Tape timer (displaying hours/minutes/seconds from zero reference).
  Search-to-Cue: Automatic access to a pre-programmed point on the tape for editing.
  PURC (Pick-Up Recording Capability): Helps prevent overlaps or “holes” when inserting new material into an already recorded program.
  Dynamic braking: Instead of mechanical brakes, the machine uses dynamic electrical braking to stop tape motion, including in power-off conditions.
  Modular construction: The recorder consists of major assemblies (transport, head assembly, audio electronics, control assemblies, power supply, meter panel, I/O panel) with multipin connectors for easier removal/servicing.

While full technical specifications (frequency response curves, noise, crosstalk, tape width, weight) are not all publicly detailed in the sources I found, here are the key spec items:

• Tape speeds: 7.5 in/s, 15 in/s, 30 in/s (inches per second). 

• Channel count: Up to 24 tracks in the 2″ format. (Some variant references also mention 16 track versions) 

• Build quality: Very ruggedly constructed with audio specs that “nearly rivalled the first digital recording machines”. 

• Original price: In 1980-era dollars, roughly US$62,500 for the 24-track machine.

• Because only a small number were built, parts availability for the ATR-124 is limited. One user’s comment:
  “While arguably the best sounding machine ever built, the maintenance is over the top. … if you don’t have a second parts machine, then you’re pretty much screwed at this point…” 

• Technicians reported that the machine, while superb, demanded significant time and commitment to keep running, especially if used heavily in a studio environment. 

• The rarity, prestige and performance of the ATR-124 make it desirable for vintage studios, tape-to-digital archiving, and for engineers seeking the “classic analog tape sound”.

• For modern use, planning for maintenance, head alignment, transport adjustment, tape path cleaning, and access to service documentation/manuals is crucial. The complexity of such a machine is significantly higher than consumer tape decks.

The Ampex ATR-124 stands as one of the ultimate analog multitrack tape machines: 2″ tape, up to 24 tracks, multiple speeds, professional features (Sel-Sync, PURC, search-to-cue), and superb build and audio quality. Its rarity, cost and maintenance demands mean it's more a studio legacy piece than a casual machine. If you're looking into operating or acquiring one, it is excellent—but you must be prepared for the infrastructure, service support, and space/power requirements.