The History of MY ITI Audio MEP-130 Parametric Mastering EQ Modules
The original 1969 ITI Audio MEP-130 Console EQ Pair, Serial #001 & #002
ITI Audio’s Beginnings
It’s crazy to think there was a time before recording consoles had EQ, not to mention parametric EQ. It all started back in the late 60s. Deane Jensen (yes, of Jensen Transformer fame) and George Massenburg (who later started George Massenburg Labs or GML) came to Burgess Macneal‘s studio in Maryland to help build a new console that was to have parametric EQs with independent control of gain, Q (bandwidth) and frequency for each band. Burgess got his recording legs by recording the Baltimore Symphony Orchestra as a teenager.
For its time, including parametric EQs in a console was extremely forward-thinking. Only one console was ever built. Shortly after, Macneal and his business partners parted ways, and his Recordings Incorporated studio was absorbed by ITI (International Telecomm Incorporated). Burgess Macneal became Vice President of ITI, which was headquartered in Hunt Valley, Maryland.
The EQ module for the console, the MEP-130, had no fixed stops, making it theoretically practical only for tracking and mixing. Its sound, however, was so good that engineers used it widely. As the technology gained attention, ITI and the audio community recognized its potential for mastering applications, planting the seed for what would later become the Sontec MEP-250.
Unfortunately, the mixing console never went beyond the prototype stage, and only one or two units were built. One console ended up in a Scandinavian houseboat studio, Blue Seas Recording Studios, which produced records for Little Feat, Robert Palmer, Bonnie Raitt, and Emmylou Harris before it sank in the Baltimore Harbor. The MEP-130 EQ was later sold briefly as a console module and then repackaged in 1971 as the MEP-230A rack-mount unit. Together, the MEP-130 and MEP-230 became the first commercially available fully parametric EQs. Like the MEP-130, the MEP-230 featured three bands of fully parametric EQ, but with a 10kHz high shelf and a selectable 50Hz/100Hz low shelf.
Potted and Unpotted Op-Amps and Filter Blocks
Potted filter blocks that could not be replicated easily and often died from thermal breakdown
The undersides of the ITI 30329 opamp and the ITI 30229 EQ Filter block.
Unpotted ITI Audio 30329 Rev B / 30229 Rev B amp and filter modules
The underside of the unpotted amps and filters.
After the first two prototypes, all subsequent EQs used potted op-amps and filter blocks, covered in black epoxy. This served two purposes: 1) acting as a heat sink for output transistors, and 2) protecting the design from being copied. It was possible to replace dead op-amps or filter blocks without soldering, this depended on ITI continuing production. When the company stopped manufacturing these components, failed modules turned the EQ into an unwieldy paperweight.
The Great Find On Craigslist
In the summer of 2017, I spotted a Craigslist ad for an ITI EQ, mistakenly listed as an “MEP-30 EQ - $100.” Curiosity got the better of me. At worst, I’d see an early ITI EQ and gather some information; at best, it was functional with extra filters and amps. It turned out to be a genuine MEP-130 module from the prototype ITI console. I spoke with the seller, Doug, who had worked with Burgess Macneal and the original ITI console. He confirmed that most of the original ITI consoles had ended up on a houseboat recording studio, many sinking to the bottom of Baltimore Harbor. This MEP-130 I acquired might be the last surviving example. At this point, I wasn’t even sure it would pass signal safely.
Joe From JLM Audio Restoration
I took the gamble and purchased it. Naturally, being a tinkerer, I opened the top panel, photographed the unit, and shared the images on Instagram. Shortly after, Joe Malone at JLM Audio contacted me. Joe, an expert in modern and vintage gear (not to mention a mensch), quickly realized from my photos that the ITI MEP-130 still had unpotted op-amps and filters - confirming it was a prototype. With his expertise, he rebuilt all the op-amps (so others could take advantage of the filters and amps), replaced the power supply with a modern compact SMPS unit with improved filtering, and restored the module to full working order. Today, this 60-year-old ITI MEP-130 parametric EQ is fully operational in my mastering studio and is ready to be used on your next record.
ITI MEP-130 Parametric Equalizer Channel Module - Technical Manual
