Category Archives: Uncategorized

Stuff Is Happening!

Times are a changin’ and audiohobby.com is now audiomaker.tech. Update your bookmarks!

I’ve moved to a new location with more lab and workshop space, and a spiffy new listening room for demos and evaluation. I’ve got some new stuff in store for this year, new projects, new videos, new merch including printed circuit boards, and a LIVE Twitch channel!

Watch this space 🙂

V-FETRON 75 UPDATE #1

Achievement Unlocked: 75 Watt Class A Zero Feedback SIT Circlotron

75wclip
Soft clipping at 75W

Because of the high input capacitance of the 2SK180’s and the gain of this circuit, we have to pull out all the stops to get our 75W beast to make audio bandwidth. Here you can see that each SIT is getting its own transformer and buffer.

vfetron75

vfetron75bench

vfetron75thd

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:

pwrsupply

power

choke

And here’s the bias supply:

bias

bias

Enjoy 🙂

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.