FYI, I rebuilt last night with both amp boards connecting to one PSU board, moving the rectifier and amps farther away from the toroid (2-3"), and twisting the signal in/out and toroid->rectifier connections. I have not yet done a disconnecting network or the other more complex steps suggested above.
There was close to no hum or buzz, but a little bit could be discerned with your ear very close to the speakers. The rectifier-> amp connections are intentionally sloppy as I intend to reconnect in dual-mono when I get a larger chassis to work with.
I am using One Pi studio speakers, which have 94dB sensitivity, so maybe they're just very good at exposing things. With music, it all sounds great. I was playing MP3s and CDs off my laptop with iTunes. The amp has no volume control built into it and I plan on building a source selector/buffer/preamp to pair with it. Speaker cables are Dayton 13Ga from Parts Express on cheapo Radio Shack posts.
One thing I noticed is that one of my amp boards gets a bit warmer than the other one when the amp is not running or at very low volumes, and the offset (~95Mv) on this channel is higher than the other (~65Mv). At normal volume the temps equalize and neither are hot, just noticeably above ambient. I have not taken it up past 30% because I live in a smaller city apartment and I think it would crack the plaster in the walls.
Overall, so far, so good. Including tools and other things (I was starting near zero so I had to buy everything) I have a little over $500 in, and could probably build the next one for $300-ish. I am very happy with both the BrianGT kit and One Pi speakers and would recommend it without reservation to someone upgrading from consumer equipment.
There was close to no hum or buzz, but a little bit could be discerned with your ear very close to the speakers. The rectifier-> amp connections are intentionally sloppy as I intend to reconnect in dual-mono when I get a larger chassis to work with.
I am using One Pi studio speakers, which have 94dB sensitivity, so maybe they're just very good at exposing things. With music, it all sounds great. I was playing MP3s and CDs off my laptop with iTunes. The amp has no volume control built into it and I plan on building a source selector/buffer/preamp to pair with it. Speaker cables are Dayton 13Ga from Parts Express on cheapo Radio Shack posts.
One thing I noticed is that one of my amp boards gets a bit warmer than the other one when the amp is not running or at very low volumes, and the offset (~95Mv) on this channel is higher than the other (~65Mv). At normal volume the temps equalize and neither are hot, just noticeably above ambient. I have not taken it up past 30% because I live in a smaller city apartment and I think it would crack the plaster in the walls.
Overall, so far, so good. Including tools and other things (I was starting near zero so I had to buy everything) I have a little over $500 in, and could probably build the next one for $300-ish. I am very happy with both the BrianGT kit and One Pi speakers and would recommend it without reservation to someone upgrading from consumer equipment.
Today I put in two trafos; 225VA 2x24V~
I also put in a new heatsink and mounted a small fan in case it'll ever be needed, but I doubt it, new sinks are that much better.
The amp is now so quiet that I thought I had broken it when plugged it in, couldn't hear humming even with your ear against the speaker.
I also put in a new heatsink and mounted a small fan in case it'll ever be needed, but I doubt it, new sinks are that much better.
The amp is now so quiet that I thought I had broken it when plugged it in, couldn't hear humming even with your ear against the speaker.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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