another firstwatt f2 build log - Page 2
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If you are living where u need 120V from the wall, grab the 250VA torroid from parts express:
I thought Hug’s BOM was missing a couple of 2.2K resistors, but I may have ordered incorrectly. Double check it. Just add a couple more to your order and you’ll be fine. Also, note your gonna need 8 of the .33 OHM 1% resistors, and the BOM lists 6. As far as the missing caps go, I just got cheap poly box caps 1uF and 10uF- any standard ones should be fine. I advise use relatively inexpensive components to get it working first, then worry about tweaking it later. It sounds really great with the K1K’s using stock parts. When you get the trafo turned just properly, this amp puts out VERY little noise.
As far as heatsinking is concerned, those conrad’s are definitely a solid choice. I went cheap and just ordered some off of Ebay, got some aluminum angle, and built them myself. My amp runs 80 C peak on 9240 mosfet itself, and the sinks run around 60. This “should” be OK, but then again I’m not driving full speakers here.
More to come later
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One more thing, what do you mean by "very little noise"? Can you actually hear any hiss in the K1000 at all? I was hoping any noise would be absolutely 100% inaudible...
Just wanted to pop back in and say that the F2 is still running great...4 years later! Only issue that has arisen is the cheap $50 transformer makes a very quiet hum that is audible about 1 foot from the amp... Otherwise, heatsinking has held up surprisingly well- I've accidentally left it on for 2 days with no issues. I no longer own the AKG K1000's, but instead have been using the amp to power a set of single driver Tekton design speakers.
Anyone have any success upgrading to the F2J? seems interesting, but medical school takes up my time now.