Purple Audio MC77 1176 Style Compressor/Limiter

Manufacturer's Description from Purple

The MC77 is a standard 19″ two space rack-mountable limiter. The MC77 recreates the audio circuitry of the revision E 1176, using modern components matched to the original.

One significant component is the input attenuator. The input attenuator that was custom made for the original revisions A-F 1176 and for the Purple MC76 by Clarostat was discontinued in 2002. It was a J series T-pad attenuator with two 600 OHM “build out” resistors to keep a constant 600 OHM load on the source and primary of the input transformer. Clarostat changed carbon manufacturers and the new carbon manufacturer was unable to make the part. Purple temporarily stopped making the MC76 to find a solution. We tried several three deck Clarostat 70 series pots in different configurations to achieve the same loading and to match the taper. We found a solution that matched the original. Based on that feedback, from hundreds of satisfied MC76 users we incorporated useful new features into the new MC77.

Features:

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
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 stainless 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.

About Manufacturer

Purple Audio was founded by Andrew Roberts in 1997.

While attending NYU’s music technology program in 1994 Andrew bought, sold and repaired recording equipment from a dorm room on the college campus.

In the fall of 1996, Andrew was introduced to John Klett who invited him to join a new repair shop in midtown Manhattan. This shop, dubbed Tech Mecca, was the new location for Manhattan Audio, a large repair facility and wiring company and Klett’s new midtown home. Andrew apprenticed under Klett and began repair on high-end audio gear.

By the fall of 1997 Purple had introduced the MC76. Soon after Purple Audio’s inaugural AES show Purple needed more space, the operation was moved to a loft in Long Island City, Queens. This large space provided overflow space for Tech Mecca’s large projects.

Purple Audio spent the late 90s and early 00s shipping the MC76 and getting involved in console and tape machine rebuild projects. Andrew studied analog circuit and logic design, seeing it in practice during field service calls to major studios in the area. While sales of the MC76 started to drop off as a result of a new competitor’s ad campaign, which in turn brought increased awareness of the MC76 product and user comments proved that the Purple Audio product was clearly superior. Distribution was finally achieved and Purple Audio began selling direct and through select dealers.

Then began a long process in console design. Andrew designed a couple of large master sections, which were retrofitted into existing consoles. The master sections went through several design revisions before the Super 8 modules were designed. The process resulted in op amps and a mic preamp design that later became the Biz. Eventually Purple delivered 16 channel portable rigs and a 32 channel full-blown console.

In 2006 the bold move was made. Purple Audio uprooted its operations in New York and shifted focus to a new location in Pennsylvania. Andrew settled in the quaint little river town of Jim Thorpe Pennsylvania, where he began restoration of a 1850’s Victorian home. Just a short drive from his new residence Purple’s new location was up and running in a 1000 sq ft. industrial complex in Weissport PA. The shop in New York still exists and is the home of Coral Sound, Exile Studios, Technical Audio, & Eisen Audio.

Upon his move to Weissport, PA in 2006 Andrew was now freed from the distractions of New York, Exile, and repair work. This allowed him to focus on the design work he had anxiously been working toward for years. With that came the completion of the new Purple Audio products in 2007 : the Action, Cans, Pants, Sweet Ten ready for the AES show with actual production the first few months of 2008.

In 2011 Purple Audio once again upgraded its facilities and purchased a historic fire company in Jim Thorpe PA, called the “Marion Hose”.

Located just blocks away from Andrews residence in Historic Jim Thorpe PA. The Building was sold to Purple Audio by the Mauch Chunk Historical Society. An entire year was devoted to the gutting and refitting of the new Purple manufacturing facility. While respecting the original historic architeture the exterior remains intact and historically correct while the interior reflects a NYC style loft with a hi-tech organic flare. The second floor is primarily for design and manufacture, and an area designated for an artist lounge, kitchen, bath and views. More to come on that.

Tube vs. FET Mic Comparison: Lauten Oceanus & Lauten Atlantis

Doug Wessling of the Sound Pure Pro Audio Team talks about the more general differences between FET, or Field Effect Transistor, mics and tube microphones. For this comparison we chose two exceptional large diaphragm mics from Lauten Audio, the Atlantis FET mic and the Oceanus tube mic. While they each have their own unique tone and vibe, both mic examples do a fantastic job showcasing the broader tonal characteristics associated with each microphone topology. First you'll hear both mics completely dry and unprocessed on our guest vocalist Beau Buttons (twitter: @beaudeas), then we'll do one more pass through with some typical vocal compression using the Purple MC77, EQ using the A Designs Hammer, and reverb from our Bricasti M7 Reverb System. In general, FET condenser mics like the Atlantis are going to provide a very accurate, detailed depiction of the sound source. Tube mics generally showcase more roundness, body, and warmth imparted into the signal, resulting in some of the detail to be smoothed out. Additionally tube mics tend to add extra depth and dimensionality to the recorded source. If you're having difficulty hearing the differences, feel free to email us at mics[at]soundpure.com for the full length hi-res audio files to compare for yourself. Both the Lauten Atlantis and Oceanus mics are available for Sound Pure's free try-before-you-buy demo program. If you'd like to set up a trial period to hear one of these incredible mics for yourself, would like to talk more about FET vs Tube mics, or just microphones in general, feel free to shoot us an email or give us a call at anytime. Thanks for watching!