Nagra IS

The Nagra IS (Integrated System, sometimes referred to as the Internal System) was introduced around 1974–1976. It represented a major shift in focus from the larger film-centric models (like the Nagra III and 4.2) toward creating a smaller, lighter, and more specialized machine for radio journalists and broadcasters.

The Nagra IS prioritized portability and speed of operation for news gathering while retaining the legendary Nagra sound quality.

The IS model came in two primary versions, often differentiated by their speeds:

Nagra IS-L (Single Speed) and Nagra IS-LT (Two Speed).

• Circuit topology:
  Fully discrete, transistor-based (no ICs)

• Channels:
  Two fully independent recording/playback channels

• Frequency response:
  Approx. 40 Hz – 15 kHz (±2 dB) at 7½ ips

• Signal-to-noise ratio:
  ~58–60 dB

• Total harmonic distortion:
  <1% at nominal level

• Equalization:
  NAB or CCIR (region/version dependent)

• Bias system:
  High-frequency AC bias optimized for professional tape stock

• Inputs:
  Two balanced microphone inputs
  Line-level inputs

• Microphone preamps:
  Broadcast-grade, low-noise design
  High headroom for dynamic material

• Microphone powering:
  Designed primarily for dynamic microphones
  Optional powering arrangements depending on configuration

• Outputs:
  Line output
  Headphone monitoring output

Each channel had independent gain control, allowing true stereo balancing in the field.

• Metering:
  Single modulation meter with channel switching
  (Some versions use summed or selectable channel indication)

• Monitoring:
  Headphone monitoring with source/tape selection

• Calibration:
  Precise internal trims for level, bias, and EQ

• Power source:
  Internal batteries (typically D-cells)

• Voltage regulation:
  Highly regulated supply for both audio electronics and transport

• Portability:
  Lighter and more compact than later stereo Nagras

• Pilot tone / sync:
  Not a primary feature

• Intended role:
  Music, effects, ambience, and general stereo recording

• Film relevance:
  Occasionally used for double-system sound, but without the industry-standard pilot-tone workflow of the Nagra III

This limitation is one reason the IV-S eventually replaced it for professional film stereo work.

While overshadowed by the Nagra III (mono film sound) and IV-S (stereo film sound), the IS remains a technically elegant and historically important machine.