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Re: Group Build National Semiconductor amp [message #10365 is a reply to message #10364] |
Wed, 18 January 2006 12:48 |
Manualblock
Messages: 4973 Registered: May 2009
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Illuminati (13th Degree) |
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Nelson has a good article in this months issue. Uses high current N-channel JFET's. The 3875 is the basis of Brian GT's and many others kit. I have one and they sound pretty good. I tried the stock unit and the modded unit and the mod sounds better. I use a nice Hammond toroidal trans and plenty of capacitor. You might want to check out the AEX article since it deals with a very different and supposedly arcane topology. Nelson claims it produces the same specs as a triode amp. No one is doing those so it might be interesting.
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Re: Group Build National Semiconductor amp [message #10368 is a reply to message #10362] |
Sat, 21 January 2006 11:30 |
Skip
Messages: 27 Registered: May 2009
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Chancellor |
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Wayne, I don't know what your goal here might be, but I've built 3 of these and will probabaly do a few more. Maybe I can bring one up to GPAF now that I've moved to Houston. This would be a great project for first time builders, particularly with a PCB such as Brian Bell's. I think Manualblock used his. I've also used Scott Nixon's, but Brian's is a bit easier. There's also a great manual .pdf. I probably won't participate in this one, but will watch and be happy to help. Off thread, my HT room with 4 Studio 2 Pi's and 1 Studio 1 Pi is now sounding fairly good. I hung rugs from IKEA on the sidewalls and it's much nicer. I'm using the Yamaha receiver recently reviewed in Absolute Sound, about $400, and it does a good job of time correction between the too-close speakers. Skip Pack
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Re: Group Build National Semiconductor amp [message #10377 is a reply to message #10362] |
Mon, 23 January 2006 11:28 |
GarMan
Messages: 960 Registered: May 2009
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Illuminati (2nd Degree) |
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Wayne, I think a group build of a chip amp is a great idea. Simple enough for everyone. Amazing performance for the project price. And if everybody on this board has one, it provides a standard to compare other components such as pre, source and speakers. One suggestion though. My experience shows that the chips are one of the least expensive parts of this project. About $6 each for a single unit at Digikey. A group buy on these would not save much money (saving of $2 to $4 per stereo amp). Transformer and (nice) chassis accounts for most of the cost. A group buy on these two items would have a bigger impact. Also might consider a group buy on high quality output caps too. gar.
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