TI-600 Development

om electronics LLC

TI-600 Development

The introduction of a high-quality audio transformer in the signal path is certainly not a new concept. Mixing boards have used transformers from input to output for decades. High quality transformers are expensive and a large part of the cost of older mixing consoles. In an attempt to build more affordable consoles engineers began to create designs that eliminated the need for transformers. The current breed of mixing boards feature wide bandwidth and high signal to noise ratio, but some might argue they lack some of the character of earlier designs. Recording engineers and producers frequently insist on using vintage processors in the signal chain when tracking for this very reason.

During the development phase of the TI-600 Goldsmith attempted to acquire some of the same UTC transformers that he discovered in the junk bin at Chess Records. Much to his chagrin the UTC transformers were no longer manufactured and available only in limited supply from resellers. He then turned to another favorite transformer from the 1970s made by Triad-Utrad. The company is still going strong but, unfortunately, does not build a suitable unit for something like the TI-600. Alas, none of the cherished iron of that era is being manufactured by the original manufacturers.

Much has been said about the elusive nature of audio transformers. Specifications often have less to do with the ultimate result than the art and science of design and construction. Two transformers with identical turns ratios and similar build can sound completely different. A well-designed transformer that is fabricated with the proper combination of materials in the correct manner can mean the difference between sonic nirvana and absolutely horrible audio. Transformers offer many advantages to circuit designers and can improve input and output designs. Good transformers can impart a degree of magic to the audio passing through it. The search was on for a suitable transformer for the TI-600 prototype.

Goldsmith contacted numerous distributors and coil manufacturers looking for units to test in his prototype. An acquaintance, who happens to be a design engineer at Sound Devices, introduced him to Lundahl transformers. Sound Devices uses the widely respected Swedish transformer in their popular USB Pre. Unfortunately, he discovered that Lundahl doesn’t make a unit that fit his design specifications. Goldsmith struck up a friendship with Dr. Don Rogers who makes high quality, custom-designed transformers and is the owner of Sescom. Rogers, a Ph.D. in electrical engineering, is the designer of the former Dean Markley line of guitar amplifiers for which he holds the patents. Dr. Rogers’ busy schedule made it impossible for Sescom to meet Goldsmith’s timetable for the prototype and the search continued.

One American manufacturer, Jensen Transformers, has arguably taken the design and fabrication of audio transformers to new heights. An untold number of manufacturers are sure to advertise the inclusion of a Jensen transformer in their design. Why, because the Jensen name is synonymous with excellence and a little name-dropping might rub off. One thing is sure: Jensen has taken the art and science of transformer design and fabrication to a very advanced state. Several stock Jensen transformers were tested for this unique application with mixed results. Working closely with the engineering staff at Jensen, a custom-fabricated transformer was developed for use in the TI-600. After extensive testing in the laboratory and in the studio we are proud to feature a Jensen transformer as the primary component in the TI-600.