Pro Audio Review July 1999

Purple Audio MC76 Limiter

Review by Russ Long

The hard-to-find UREI 1176 limiter continues to grow more rare as the years pass. An 1176 in good condition can pull in more than $2,000 dollars if the right buyer is found. It wouldn't surprise me if that price tag doubled over the next decade. No need to worry, though. Purple Audio has arrived to save the day with the Purple Audio MC76, the modern day rebirth of the famous UREI 1176.

The electronics of the MC76 are modeled after the 1176LN: black-face revision E, except Purple Audio has gone the extra step to include a stereo link circuit. Like the 1176, the MC76 is a mono Field Effect Transistor (FET) peak-limiting amplifier. Like the 1176, the MC76 also uses an FET-based circuit to create a warmth that's hard to believe isn't tube-based.

The MC76 even looks identical to the 1176 except for the bright purple color. If I didn't know better I would swear that Purple Audio allowed the color-savvy folks over at HHB to vote in the color scheme election.

Features

The rear panel of the transformer-balanced MC76 is equipped with a female XLR for audio input and a male XLR for audio output. Both are wired pin two hot. The unit is powered by a Zener shunt-regulated power supply.

The front panel has two large knobs, two small knobs, a meter and two columns of buttons. The large knobs adjust input and output level, the small knobs adjust attack and release times. Attack time can be set from 20 microseconds to 800 microseconds and release time can be set from 50 milliseconds to 1.1 second. Turning attack control counterclockwise until it clicks, disables the limiter and the unit can be used as a line amp.

The first column of four buttons selects the compression ratio at 4:1, 8:1, 12:1 or 20:1. As on the 1176, the age-old more-than-one-button-at-a-time trick works nicely. The first three buttons on the second column select the desired meter function. The meter can be selected to monitor gain reduction or output level referenced to +4 dBu or +8 dBu. The last button on the second column turns the power off. Selecting any meter function (+8, +4 or GR) turns the unit on.

The MC76 boasts a frequency response of 15 Hz to 80 kHz +/- 1 dB. The unit uses discrete transistor electronics and features transformer balanced inputs and outputs. It uses the highest quality components and has a wonderful sound.

In use

I have used the MC76 on everything from percussion to electric guitars, from vocals to strings, and have always had pleasing results. Like the 1176, the MC76's compression is smooth, and small amounts of compression are virtually undetectable. I found myself using the 12:1 setting most often, but each ratio was used from time to time.

The unit also performs extremely well on bass guitar. I've been working on some Roy Orbison recordings over the past several weeks and the MC76 has been indispensable. The Orbison songs were recorded in the mid-'80s and we have been replacing some of the tracks and remixing others for an upcoming movie soundtrack. We replaced the electric bass with upright bass, which I recorded to two tracks, one direct and the other with a microphone.

For the direct track I used a Demeter tube DI through a Hardy Preamp through an MC76. For the mic track I used the Royer R-121 ribbon microphone through a Daking preamp/EQ module through a MC76. The musician (who plays upright on records every day) loved the tone and punch of his instrument and made sure I gave him exact details on the signal path. On the Orbison project I also used the MC76 on electric guitars, backing vocals and percussion. Like the 1176, the MC76 sounds unbelievable on the tambourine.

I had fantastic results using the unit on lead vocals. I mixed an independent project for an artist from Pennsylvania last month and MC76 became the lead vocal compressor on every song.

Summary

Anyone who loves the 1176 will find themselves falling for the MC76. It sounds wonderful and its versatility should make it a welcome addition to any studio. For the engineer who loves the sound of the 1176 but wants the reliability of a newer device, the MC76 is the answer.

Russ Long, a Nashville-based producer/engineer, owns The White House and The Carport recording studios. He is a regular contributor to Pro Audio Review.