THAT and ATI Ink Exclusive License Agreement for
Advanced Balanced Output Stage

THAT and ATI Sign License Agreement

Milford , MA - THAT Corporation and Audio Toys, Inc. have entered into an exclusive license agreement under which THAT will design and manufacture integrated circuits incorporating ATI’s patented "Electroformer" balanced output stage technology. Using its own innovative adaptation of the Electroformer, THAT has developed a design that significantly improves on the circuits used in conventional output stages. ICs based on the advanced circuitry are expected from THAT early in 2001. The agreement was signed at the 108th Audio Engineering Society Convention in Paris, France.

"The combination of ATI’s circuit technology with our robust complementary Dielectric Isolation IC process will advance the state of the art in balanced output stages", said Win Craft, THAT’s VP for Marketing and Sales. Larry Droppa, ATI’s President, explained the technical advantages of his circuitry. "Active balanced output stages use both negative and positive feedback to maintain the two output currents in balance. In the conventional approach, the balance between positive and negative feedback is dependent on precise resistor ratios, which requires ‘knife edge’ precision to maintain stability. The genius of ATI’s technique is to separately control the common-mode and differential feedback loops, which greatly enhances stability under real-world circuit variations."

Gary Hebert, THAT’s Chief Technology Officer and the designer of the planned ICs, will explain how he has adapted the basic ATI concept, originally developed by Chris Strahm, to improve clipping performance in a paper offered at the 108th Audio Engineering Society Convention held in Paris during February of this year. "When a conventional balanced output stage clips into a remotely grounded single-ended load, high current flowing through the ground return results in audible artifacts that sound much worse than simple clipping," he explained. "But our design always maintains equal and opposite currents in both driven lines, even with such single-ended loads. This eliminates ground currents, preserving the purity of the sound." THAT has applied for a patent on the concepts involved.

Balanced output stages are used primarily in professional audio, broadcast, and telecommunications products to convert audio signals into a 2-wire differential format. These balanced electrical signals can then be transmitted between different pieces of equipment with less noise pickup than the single-wire ("single-ended") format used in consumer products. Because balanced outputs are often connected to single-ended inputs in practice, their performance in this mode is an important consideration for equipment designers.

The first balanced output IC to be introduced with the new design, the THAT 1646, will be pin-compatible with existing ICs from other manufacturers, and priced competitively. A low-offset version is also on the drawing board.

About Audio Toys
Audio Toys, Inc., a part of the ATI Group, is a leading manufacturer of high quality sound reinforcement equipment for the professional audio industry. ATI was founded in 1988 and is located in Columbia, Maryland. The company has played an important role in determining the direction of the design and usage of touring sound consoles. ATI’s products are utilized in fixed sound installations, recording studios and touring sound systems, and include the Paragon Sound Reinforcement Console, Pro6 Audio Processor and the 8MX2 Preamp/Mixer. ATI has been awarded a design patent both for the Electroformer and for its unique compressor circuitry.

About THAT Corporation
THAT Corporation, founded in 1989, designs and sells high-performance analog integrated circuits for professional audio manufacturers. THAT’s ICs include analog input and output stages, digitally controlled low-noise preamplifiers, Analog Engines® and its original line of voltage-controlled amplifiers (VCAs) – all used throughout the pro audio industry. The company also licenses patents, trademarks, and other intellectual property to the TV broadcast and reception industries. Licensed products include the dbx-tv® Total™ series of audio enhancement technology and digital implementations of legacy TV audio receiver standards. The company is headquartered in Milford, Massachusetts, with offices in Milpitas, California.

For more information, contact:
  THAT Corporation, 45 Sumner Street, Milford, MA 01757-1656 , USA
  Telephone: +1 (508) 478-9200; Fax +1 (508) 478-0990
  Email:

Editorial Contact:
  Ken Nevard, IC Marketing Manager
  Tel: +1 (508) 478-9200 x108
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