A fully active balancing direct box without fet's question.

[KR]

There used to be a -fully- active direct box made in the 70's that was designed without transformers, didn't use fet's and it was balanced XLR output. It was phantom or 9-volt powered. Larry Comara made them and no info can be found or sourced. What type of circuit could it have been? Please chime in. I wonder what Ron Wickersham would say about this.

[elwoodblue]

There's a couple pics on this thread...


https://www.gearslutz.com/board/so-much-gear-so-little-time/47750-has-anyone-heard-quot-fat-box-quot.html

[hieronymous]

Looks a lot like a brass colored blue box from the outside? Pics from the gearslutz thread that elwoodblue linked to, though it's worth reading the thread too.

[KR]

That's the Fat Box I used in the 80's. The only info Larry Comara has shared is that it's transformerless and no FET's used. Holland Synthesizer makes a Transformerless/no FET 18 volt unit called a TBD. Still wonder what type of circuit Comara used. I often wondered if the Countryman Type 85 was a commercial realization of the Comara design, but I see the Type 85 uses FET's.

[edwin]

That's the Fat Box I used in the 80's. The only info Larry Comara has shared is that it's transformerless and no FET's used. Holland Synthesizer makes a Transformerless/no FET 18 volt unit called a TBD. Still wonder what type of circuit Comara used. I often wondered if the Countryman Type 85 was a commercial realization of the Comara design, but I see the Type 85 uses FET's.

Doesn't the Type 85 also have a transformer?

[KR]

Edwin, I just saw your post. You're right. The Type 85 is transformer balanced.