Recording Magazine January 2000

Purple Audio MC76

A modern-day recreation of the classic UREI 1176LN compressor?

Review by Dave Martin

Purple Audio MC76

There's something strikingly familiar about the Purple Audio MC76. It's not the color of the front panel (though I did have a tie-dyed T-shirt in 1974 that was exactly that color, and there was a teacher whose neck would turn a similar shade when some of us came to class a few minutes late...), and it's not the model number (though if you were awake the day your math teacher discussed Roman numerals you'll figure it out).

But really it's quite simple. A couple of years ago (the MC76 was introduced at the 1997 AES convention in New York) the price of vintage gear was skyrocketing: a UREI 1176LN was selling for $2500 - $3500... when they were available at all. So Andrew Roberts and John Klett formed Purple Audio to design and build their own version of the 1176.

Since there were many versions of the 1176, from the original tube-powered 176 through the blue stripe, black-faced and silver-faced models... as well as different revisions (A through F), Roberts and Klett based the MC76 on the E revision of the 1176LN, which most compressor connoisseurs feel to be the best sounding version of the original.

The MC76 boasts two large Input and Output controls, and two smaller knobs that control attack and release times. The unit can be bypassed by turning the attack control counterclockwise. A row of buttons to the left of the large VU meter offers compression ratios of 4:1, 8:1, 12:1, and 20:1. The buttons on the right control the meter, showing either gain reduction or input levels calibrated to +8 dBM or +4 dBm. Power implementation is complete, with an on/off switch and an fused IEC detachable AC connector with switchable voltage selection. There's also a lug to facilitate chassis ground.

The MC76 is not a complete clone of the UREI-it uses XLRs for I/O (with the pin out configuration stenciled the between the connectors) rather than the barrier strips common in the original units. The MC76 is also easier to link than its predecessor; the UREI required an 1176SA (stereo adapter), which some engineers claim were problematic at the best of times.

The MC76 has link circuitry built in, with two 1/4" jacks, along with offset adjustment and a phase switch on the back of the box. This circuitry is powered with an AA battery.

The MC76 has transformer-coupled inputs and outputs, discrete transistor electronics, and a Class A output amplifier. Attack times are adjustable from 20 to 800 microseconds, release times from 50 milliseconds to 1.1 seconds, and the MC76 is capable of up to 45 dB of gain (with no limiting).

The manual is quite readable and it offers information applicable to all levels of users, from the simple explanation of compression and limiting aimed at the novice to quite detailed instructions on how to service the unit (for techs and repair people). Besides, how can you not like operating instructions that end with "7) Experiment"? (And speaking of experiments, both the 2-button and the 4-button trick work. If you don't know what I mean, forget I ever said it....)

How do they sound?

Quite good. If you're used to the distinctive sound of an 1176, you won't find the Purple to be a great surprise, though to my ears the MC76 is a little bit brighter and may have a little bit more of an edge than the originals.

While the MC76 doesn't sound exactly like any of the original 1176s that I've played with, it still sounds like an 1176. The sonic differences between an 1176 and the MC76 are pretty subtle, and both the monitoring environment and the signal passed through the box can change your perception of these differences.

It's also true that every original 1176LN sounds different, for a variety of reasons. Electronic components change differently as they age; units that have been well maintained-having dried-out capacitors replaced, for example-will sound better; and it wasn't uncommon for a studio or broadcast facility to modify electronic equipment to suit the tastes of the engineers who used it. So it's quite possible that the Purples sound like brand new 1176s.

Regardless, the MC76-and for that matter the 1176-is a little edgier than a comparably priced a tube limiter, and that's not a bad thing; I've used that edginess to make a dark vocal sound out in a track a little and to help keep a kick drum at the front of a mix. In fact, I've used my Purples pretty much anywhere I need to keep a track big while controlling the dynamics.

It's safe to say that I haven't done a mix in a year and a half without my pair of Purples somewhere in the processing. I've tried them on all sorts of instruments and voices, and they work well everywhere. If you're in the market for a the sound of a vintage piece of gear but don't want the hassles, the Purple Audio MC 76 is an excellent choice.