ProReplicas - vintage audio equipments for recording

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:  http://www.attackmagazine.com/features/my-studio/chopstick-johnjon-suol (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”.)

* samples

(bypass is switchable on knob of attack, via extreme rotation in left)

* pictures

* construction details

The original schematic for the revision G from 1979 year.

List of key components used in the replica:

• 1 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.
• 2 x Motorola MPS U05 / MPS U55, original pair of transistors used in block of output amplifier. Currently is no longer produced.
• 1 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.
• 2 x 2N5087, original transistors used in block of output amplifier.
• 3 x 2N3391A, original transistors used in block of pre-amplifier.
• 2 X 2N5457, original and matched for pair FET transistors.
• 4 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.
• 1 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