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The MC77 Limiter

The MC77 recreates the audio circuitry of the revision E 1176, using modern components matched to the original.

Starting in 1997 Purple started making the MC76, an 1176 type compressor based on the D & E version units. (MC is 1100 in roman numerals) At the time the 1176 was not available from any manufacturer. Coming from the repair background it was clear a better built, more road worthy unit could be build and sold new for less than the 20+ year old units that were coming through the shop. After another manufacture brought an 1176 clone on to the market Purple introduced the MC77. The MC77 added new features that were lacking from the original. Thousands of units later Purple keeps its parts and build quality high. Using parts that will last decades. Have a look inside and see for yourself. Toroidal power transformer, the best interlocking switches on the market, conductive plastic potentiometers. Quality for longevity.

New in 2019 Plugin Alliance

Available at  Digidesign’s Bomb Factory:

The Purple Audio MC77 is meticulously modeled and personally approved by Andrew Roberts of Purple Audio, Inc. It is a spot-on digital replica of Roberts’ acclaimed MC77 Limiting Amplifier, which in turn is an update of his classic MC76 hardware unit. Representing a different take on the 1176-style FET limiter, Purple Audio MC77 gives you access to all the goodness of the original with the convenience and flexibility only a plug-in can offer.


*This plugin may no longer be supported by your version of Pro Tools based on Avid’s specifications.


Inherited from the MC76

• Discrete Transistor Audio Path Electronics

• Single Element Class A Output Amplifier

• Transformer Balanced XLR Inputs and Outputs

• Zener Shunt Regulated Audio Power Supply

• Compression Ratios – 4:1, 8:1, 12:1 and 20:1

• Fast Attack Time – 20 to 800 microseconds

• Release Time – 50 milliseconds to 1.1 second

• Gain of 45dB (full gain with no limiting)

• Ruggedized Design – PCB stiffener, chassis mounts

• Purple Anodized Aluminum Front Panel

• 3 Year Warranty*

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NEW on the MC77

• True Bypass via sealed relay w/front panel switch

• Improved stereo linking w/front panel switch

• Sidechain insert loop or key input w/front panel switch

• Buffered VU meter can monitor input or output level at +4dBu

• LED meter lights that don’t burn out

• Heavy gauge black cold rolled steel enclosure

• 155v/230v operation switchable from rear panel

The MC77 should be fitted with 1/4A slow-blow @ 110V, 1/8A Slow-blow @220V.
1/4A slow-blow available from Mouser or Digikey in the US.

MC77 Manual & Schematic

PDF Recall Sheet

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MC77 Limiting Amplifier
Average rating:  
 2 reviews

1073 > MC77 = Magic


Solid piece of gear that not only can be used on a variety of instruments and processing but is very musical as well. I love it on bass guitar, toms, guitars, vocals, the list is endless. A definite must for any studio.

I had the pleasure of visiting with the team at purple and saw how their products are made. They take great pride in what they do and are extremely knowledgeable. This kind of attention to detail and customer service is quickly fading away here in the fast paced technology driven world. You won't be disappointed by investing in Andrews products.


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