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Ironamp Details

Summer has been really busy and I don’t think I’ll be able to do a lot of audio related stuff until later in the Fall. Here are the details for the Ironamp power and bias supplies I’m using. The transformers I used were custom wound by Edcor. I built monoblocks, so they’re for one channel. The primaries are 115V @ 60Hz, and there are two secondaries, one 80V @ 2A, and one 21V @ 50mA, 150VA.

Here’s the main power supply:




And here’s the bias supply:



Enjoy ūüôā

P.S. If you find yourself thinking about sending me a cranky email to tell me what I should have done differently, or why such-and-such is better, or that so-and-so on the forums says you shouldn’t do that, I want you to know that I value your time, and that I really suggest you don’t waste it being cranky. ¬†Do whatever¬†you want to do. ¬†Your energy will be better spent on your own creative efforts.

Linear Systems Releases JFETs Into The Wild

The silicon wizards at Linear Systems have been cooking up a special batch of JFETs in their secret underground laboratory.  The LSJ74, a replacement for the Toshiba 2SJ74, will be sold exclusively to the DIY community through  This is a nice nod to the audio enthusiasts who have been pushing for these parts, and will no doubt put them through their paces before they are released to OEMs.

Linear Audio Volume Six Out Now!

v6 cover 150pix

I’ve written an article titled “A Concise Model for Static Induction Transistor IV Characteristics”, which will appear in Volume 6 of Linear Audio.¬† Linear Audio is a book-zine published twice yearly by Jan Didden.¬† Each issue is packed with quality technical articles you’re sure to enjoy.¬† Copies of Linear Audio can be purchased at

The new article details a new model for SIT characteristics and includes software you can use to make your own models.  I hope you find it useful.