Replica of classic compressor UREI 1176LN / revision G

This replica is a faithful reproduction of the classic compressor Urei 1176LN revision G, from the electronic point vision it's practically original device made 40 years later. Revision G as the first had removed the input transformer, and replaced via a differential amplifier. This change gave lower distortion THD than in earlier revisions A-F. Company Urei has produced 598 pieces of this revision.

Specification electrical:

  • INPUT: XLR, balanced bridging, differential amplifier.
  • MAXIMUM GAIN: 45 dB, +/- 1dB
  • FEREQUENCY RESPONSE: 20-20,000Hz, +/-1dB.
  • OUTPUT: XLR, floating, transformer isolated.
  • SIGNAL TO NOISE RATIO: Greater than 81 dB at threshold of limiting, 30 Hz to 15 kHz.
  • ATTACK TIME: 20 microseconds to 800 microseconds.
  • RELEASE TIME: 50 milliseconds to 1.1 second.
  • COMPRESSION RATIO: 4:1, 8:1, 12:1 and 20:1.
  • POWER SUPPLY: 115 or 230 AVC, 50/60Hz, less than 10W.

Independent review about units 1176LN revision G from ProReplicas. This is one snapshot from whole article in Attack Magazine. More: (This pair of units, was one of the first units and had the front panels with original name brand, which are currently replaced by name “ProReplicas”.)

studio picture of UREI 1176 Rev.G

* construction details

urei 1176 scheme

The original schematic for the revision G from 1979 year.

List of key components used in the replica:

  • Op-amp NE55321 x Op-amp NE5532, applied in revision G and later, in a differential amplifier on input, instead of the input transformer UTC 0-12. In Urei 1176LN this one op-amp was from a Signetics company, that designed it, today NE5532 Signetics is recognized in the audio environment as the best NE5532. Currently is no longer produced.
  • MPSU05-552 x Motorola MPS U05 / MPS U55, original pair of transistors used in block of output amplifier. Currently is no longer produced.
  • 51171 x 5117, original, very mysterious and exotic transistor, which was produced only for the Thomas Organ Company about 70's years. He was also used in legendary wah-wah pedals Cry Baby. Currently is no longer produced and is very difficult to obtain.
  • 2N50872 x 2N5087, original transistors used in block of output amplifier.
  • 2N3391A3 x 2N3391A, original transistors used in block of pre-amplifier.
  • 2N54572 X 2N5457, original and matched for pair FET transistors.
  • 2N50884 x 2N5088, transistors used in block of control amplifier. They are used instead of a 2N3707, this is only one exception, 2N3707 though no longer manufactured are still available but among them very difficult to find pieces with H.F.E. 250 or above, like is recommended in a schematic. In replicas Purple Audio MC76 are also used 2N5088 as a replacements of 2N3707.
  • B111481 x B11148 or 22-0018, original output transformer used in revision F and G of Urei 1176LN and also in LA-3A. Currently is no longer produced.

The rest of the electronic components is high quality: resistors metal film 1%, capacitors Panasonic FC/Wima/Nichicon-Muse, potentiometers Alpha, professional VU-meter with lighting. Additionally I have employed anty-interference EMI power filter.

* pictures of inside

  • urei 1176
  • urei 1176
  • urei 1176