Sure gary! I built an Orion clone using LM3886 as the amplifiers. Tweeters are 27TDFC with
waveguides, woofers are RS225-4, subwoofers are RSS315HF. I used a DCX2496 as the crossover. Each driver has a separate amplifier.
Details on power amplifier: My amps were built into the speakers, 6 channels on each speaker (I have the 2 spare channels in case I needed to bridge for more woofer output).
I used an Antek 600VA 20V + 20V transformer for each 6 channel amplifier (overkill, and probably could be easily halved for my purposes.) Each is charged through a soft-start as seen on
Rod Elliott's page. If I had gone with two 300VA transformers instead (and not powered them on at the same time, maybe I would not have needed the soft-start.
There is one bridge rectifier on each transformer, with pairs of 10000uF (could probably be smaller with no ill effect) capacitors for each amplifier. Each amplifier also has local 1500uF, 100uF, and 1uF bypass caps (on the
www.chipamp.com boards, very close to the chip supply pins). The large capacitors are mounted close to the amplifier boards, with wire leads to the rectifier, and star grounded to chassis ground. The idea here is to have current surges come from the capacitors, which are somewhat isolated from the transformer and rectifier by the small lead wire resistance. This is all experimental on my part, but it makes sense to me, and seems to work well.
The chipamp.com boards can be had with power supply boards that use discrete diodes. I cannot comment on using multiple rectifier bridges on one transformer, though it doesn't seem like a problem to me. You can probably find discussion on this on the chipamp forum, but I invite anyone reading this thread that has personal experience with multiple rectifier boards on the same transformer to comment on the suitability of this application.
Note that with my application L and R channels are inherently separated. Alot of people advocate separating L and R power supplies, I can't personally comment that I've heard a difference, though the theory makes sense. If you draw all of the power from one transformer and one rectifier, I would recommend getting the heftiest metal case rectifier you can find. I got mine from
www.apexjr.com. I didn't need them, but uou can also get binding posts from ApexJR for a good price. Come to think of it, my filter capacitors were also from ApexJR.
Some people report having issues with hum if their RCA jacks are grounded to chassis ground, mine are on a non conductive panel and as such are inherently isolated from chassis ground. I used simple twisted pair wiring from the RCA jacks to the amplifier boards.
My system is currently in pieces and in boxes. I never got around to building a proper loudspeaker enclosure for my bachelor pad and have gotten married, moved into an apartment, bought a house, remodeled it, and moved into said house in the last 8 months, so it may be awhile before I can ever get around to playing with that system again. I still have to tile one bathroom tub surround and finish remodeling the garage!
Regarding extra parts laying around, I don't even want to think about how many boxes of parts I have that aren't getting used. Perhaps once I've finished my major home projects and have a functional workshop/garage, I can inventory my spare parts and post them in the appropriate section.
Best Regards,
David
