After a 20+ year hiatus as an electronic tech I've pulled out my old scope, variac and DMMs. They all still work, but I'm pretty rusty myself. and most of my books are gone.
I decided to build a chipamp and may have rushed things a bit in my parts selection. I picked up two transformers and four boards on ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersion&item=170437050006&view=all&tid=482789703007
28Vx2 200VA Toroid Transformer DIY HiFi Power Amp Kit - eBay (item 250649543698 end time Jun-18-10 12:38:43 PDT)
After reading through the diy forums I'm starting to think the LM3875 isn't that great a chip anymore and the supply voltage will be too high for reliable operation. I plan to drive 2 different pairs of 8 ohm speakers as surround sound on my patio. I also was thinking of finally finishing that Phoenix Systems Parametric Equalizer project from Popular Electronics that I bought pcbs for long ago, and try to use it as some sort of preamp. It's supposed to go in the tape loop. Can I just feed it the headphone out from an mp3 player or Squeezebox Radio? Where's the best place for a volume control?
I decided to build a chipamp and may have rushed things a bit in my parts selection. I picked up two transformers and four boards on ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersion&item=170437050006&view=all&tid=482789703007
28Vx2 200VA Toroid Transformer DIY HiFi Power Amp Kit - eBay (item 250649543698 end time Jun-18-10 12:38:43 PDT)
After reading through the diy forums I'm starting to think the LM3875 isn't that great a chip anymore and the supply voltage will be too high for reliable operation. I plan to drive 2 different pairs of 8 ohm speakers as surround sound on my patio. I also was thinking of finally finishing that Phoenix Systems Parametric Equalizer project from Popular Electronics that I bought pcbs for long ago, and try to use it as some sort of preamp. It's supposed to go in the tape loop. Can I just feed it the headphone out from an mp3 player or Squeezebox Radio? Where's the best place for a volume control?
your link for the kits you selected doesn't work (or is it just me?)
transformer voltages are too high
For 8 ohm loads they should be 25Vx2
You might want to build regulator circuits ,but that might prove to be far to much effort and a waste of power.
here is an example of such a circuit:
PA100 DIY 2x LM3886 in parallel gainclone audio amplifier
transformer voltages are too high
For 8 ohm loads they should be 25Vx2
You might want to build regulator circuits ,but that might prove to be far to much effort and a waste of power.
here is an example of such a circuit:
PA100 DIY 2x LM3886 in parallel gainclone audio amplifier
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