ProReplicas - vintage audio equipments for recording
Replica of classic compressor UREI 1176LN / revision D
The faithful reproduction of the classic compressor Urei 1176 revision D. Units of revision D were the first revisions with built-in of low noise mode LN and had black front panel with characteristic logo UREI over the VU meter. This revision had audio transformers on input and output, and in detail of constructions, was it transition the between the first and the last revisions of Urei 1176. Sound these units is very vintage and is recognized by many sound engineers as pattern for compressors Urei 1176. Company Urei has produced 1092 pieces of this revision. Presented replica is based on original schematic of revision D from 1970 year and has applied a specially audio transformers for this revision recreated by Ed Anderson.
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.
* pictures
* construction details
The original schematic for the revision D from 1970 year.
List of key components used in the replica:
The C-3837-1 is a reproduction of the UTC O-12 input transformer used in the early Rev.A-F FET compressor models. Faithfully recreated by Ed Anderson. On request is possible use original transformer UTC O-12 in your replica.
The 5002 is a reproduction of the output transformer used in the early Rev.A-E FET compressor models. Faithfully recreated by Ed Anderson. On request is possible use original transformer UA-5002 in your replica.
2 x 2N5457, original and matched for pair FET transistors.
4 x 2N3391A, original transistors used in block of pre-amplifier and output amplifier.
1 x 2n3053, original transistor used in block of output amplifier.
1 x 2n3707 discontinued, original transistors used in block of output amplifier.
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.
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.
