Urei 1178

Urei 1178 Stereo Compressor

The Urei 1178 compressor was introduced in 1979 by Universal Audio. It became a popular choice in recording studios during the late 1970s and throughout the 1980s, and it remains a sought-after vintage piece of audio equipment today.

Urei 1178 Stereo Compressor Details

The Urei 1178 is a dual-channel version of the popular Urei 1176LN Peak Limiter, widely used in recording studios, broadcast stations, and sound reinforcement setups worldwide. This Dual Peak Limiter is designed for applications that require the processing of two audio channels, ensuring a balanced output across both channels. The two limiters within the Urei 1178 are meticulously matched for accurate tracking, making it ideal for precise stereo applications.

Both channels’ attack and release times are controlled simultaneously, while the input and output levels can be adjusted independently. In stereo mode, a front panel switch links the gain reduction amplifiers of both limiters. This allows the limiter with the higher peak amplitude to reduce gain equally across both channels. Alternatively, switching to single-mode lets each limiter operate independently, offering the user flexible control.

The Urei 1178 is engineered to deliver performance comparable to the single-channel 1176LN, using FETs as voltage-controlled resistors for limiting. Its unique circuitry enables intense limiting without additional distortion, and the compression ratio can be tailored for different audio programmes. The Urei 1178 ’s gain structure provides an excellent signal-to-noise ratio, even under typical operating conditions.

It includes dual, backlit meters on the front panel that can be set to display either the gain reduction amount or the output level, with reference points of +4 dBm or +8 dBm. Users can also select between average signal metering (VU ballistics) and peak metering. The limiter requires only 3½ inches of rack space and operates on either 100-125 VAC or 200-250 VAC at 50/60 Hz.

Features

  • Two independent Peak Limiters with perfect tracking when used in stereo mode.
  • Attack time front panel adjustable from 20-800 microseconds. Independent of peak duration or frequency.
  • Release time front panel adjustable from 50 ms to 1.1 seconds.
  • Pushbutton selection of four compression ratios, to satisfy various program requirements.
  • Balanced, transformer outputs.
  • Switchable meter ballistics (VU, peak).

 

While the 1178 is a vintage piece of equipment, it is still highly regarded in the audio industry and sought after by many professionals for its unique sonic qualities. Bob Clearmountain is a highly respected audio engineer and mixer known for his work with numerous iconic artists and bands. One of the notable aspects of Bob Clearmountain’s mixing style is his use of the Urei 1178 compressor. Clearmountain has been known to incorporate the Urei 1178 into his mixing chain for various purposes, including drum and vocal processing.

The fast attack time of the 1178 can help control transients and shape the dynamics of instruments and vocals, which aligns with Clearmountain’s mixing philosophy of enhancing the clarity and impact of individual elements in a mix. While Clearmountain’s approach to using the Urei 1178 might vary from project to project, it’s often cited as one of the tools in his arsenal that contributes to the signature sound of his mixes.

Bob Clearmountain Urei 1178

Bob Clearmountain’s effects rack showing the Urei 1178 Compressors

Specifications

  • Input: Balanced bridging, differential amplifier
  • Input Impedance:
    • 20 kΩ used as balanced input
    • 10 kΩ used as unbalanced (single-ended) input
  • Maximum Input Level: +20 dB maximum (Reference: 0.775 volts RMS)
  • Maximum Gain: 45 dB, ±1 dB
  • Frequency Response: ±1 dB, 20 Hz – 20,000 Hz
  • Output: Floating, transformer isolated
  • Output Load: 150 Ω or greater
  • Maximum Output Level:
    • +24 dBm into 600 Ω load (12.28 volts)
    • +20 dBm into 150 Ω load (7.75 volts)
  • Distortion: Less than 0.5% THD, 50 Hz to 15 kHz with limiting, at 1.1 seconds release setting
    • Note: As with all limiting devices, distortion of low-frequency peaks increases with faster release time
  • Signal to Noise Ratio: Greater than 81 dB at threshold of limiting, 30 Hz to 15 kHz
  • Attack Time: Less than 20 microseconds for 100% recovery; adjustable to 800 microseconds with front-panel control
  • Release Time: 50 milliseconds minimum, 1.1 seconds maximum (for 63% recovery). Adjustable with front-panel control
  • Threshold vs Output Level:
    • Compression Ratio Settings: 20:1, 12:1, 8:1 and 4:1
    • Input Level at Minimum Limiting Threshold ±2 dB: 20:1: -24 dB, 12:1: -25 dB, 8:1: -26 dB and 4:1: -30 dB
    • Relative Output at Threshold*: 20:1: +10 dBm, 12:1: +9 dBm, 8:1: +8 dBm and 4:1: +7 dBm
  • Dimensions: 483 mm x 89 mm x 203 mm
  • Weight: 5 kg

*Note: With output gain control set to provide a reserve of approximately 10 dB.

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The details provided above are drawn from historical documents like advertising brochures or user manuals. They’re shared without bias or review. This info is given solely for your consideration, helping you gauge its usefulness to you.

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Timeless Studio Powerhouse

By Peter Oldman

Sound Quality 95%
Build Quality 80%
Usefullness 100%
Mojo/Funk 90%
Reliability 90%

The Urei 1178 compressor is an absolute beast! It’s been a trusty companion in my studio for years. The transparency and control it offers are second to none. This thing just oozes classic vintage vibe, and it’s a secret weapon for achieving that pro sound. If you’re serious about audio, you need this in your setup. An absolute gem!

Used it? Leave your rating and review.

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