Tag Archive for Iron Pre

Iron Pre

Well ,it started as solution for two customers; both having my Babelfish amps, both driving Dynaudio Contour 1.3 with them.

Whatever solution they had for preamplifier in that time, they weren’t on par with amp quality ….. so logical development of situation is to mate  amps with line stage simple enough but not simpler than necessary …… simply put -preamp made in same manner.

After some chat , consensus was that “plain” buffer (so , no gain ) is adequate,so I decided to make a quick mockup with buffer pcb I had from yore,as part of Poor Serbian Man Lightspeed project.

Frankly – not “plain” buffer anymore , but I simply couldn’t go with less .

Basically-4 separate buffer cells , and simple but witty bipolar (+/-12V) shunt reg on board.Cells are made of scarce and expensive Toshiba JFets (2SJ74BL , 2SK170BL) as source follower. In this case , just two buffer cells are populated, as not needed more for unbalanced operation. For more details, it’s easy to check my signature on diyaudio.com .

Schematic sketch and first proto , conveniently put in dreky casset deck case :

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