Dave, the Pioneer has since been sold off in favor for a more 'purist' setup. I'm currently using Audio-GD NFB12 Active Preamp / DAC, with a Class D Audio SDS-224 amplifier. Great combination that easily trumps the Pioneer in most every way, especially 3-dimensional sound staging. It doesn't accent any single frequency as the pioneer did (highs and lows) but does a nice job staying out of the way of the music.
You guys can see my build of the amp and speakers alike at Http://Szaiontz.imgur.com to see my builds. I've had this combination on a wide array of speakers and feel it's a very neutral setup for most any speaker.
You guys can see my build of the amp and speakers alike at Http://Szaiontz.imgur.com to see my builds. I've had this combination on a wide array of speakers and feel it's a very neutral setup for most any speaker.
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A class D amplifier in a wooden box is likely to be radiating RF into everything. It could be part of the problem.
dave
The way a Class D amplifier works is that it takes the incoming signal, chops it into a very high frequency pulses (pulse code modulation) and then uses that to switch the output devices on & off. By its very nature it sprays the modulation frequencies & harmonics all over. The LC filter at the output before the speakers filters this out of the drive signal (note that optimum LC values will differ depending on speaker impedance). Just like a computer the amplifier itself should be in a metal box or farady cage that keeps any "spray" inside.
dave
dave
Well that's not good. Perhaps I should hook up the shield wire from the transformer to help against this. I have one of Antek's new transformers with a purple shielding wire wrapped around the transformer that I just left unconnected. It also doubles as a chassis ground. I'd imagine that if I took that chassis ground wire and connected it to the IEC ground that it would reduce or eliminate the RF spray.
Alright, I just had a long winded chat with a good electrical engineer friend of mine. He and I agreed that the easiest way to block the RF frequencies would be to line the inside of the box with foil tape and connect it to ground. I'll knock that out this weekend. Hopefully it will improve things a bit. I'll also hook up the transformer shield wire to the IEC ground to help shield the transformer a bit as well. I've already programmed the router to cut out pieces so I can do the 6.35liter (.224ft^3) enclosure so when that's done we'll see how everything does.
When I was pulling the speakers from the cabinets this morning I noticed that there was quite a bit of pressure on the speaker chassis which was caused the distortion mentioned in another thread from contorting the actual frame and causing the suspension to foul during playback. I will open up the cutout to release all pressures on the actual speaker itself on this new box. From previous experience with CHR-70's in sealed enclosures I think I'll be pretty happy the way it all comes together. Now my only question is, what flavor of veneer should this gray coned driver be treated to?
Thanks for the input guys. Also, Buzz, what variation of enclosure are you on now and what was your favorite so far?
When I was pulling the speakers from the cabinets this morning I noticed that there was quite a bit of pressure on the speaker chassis which was caused the distortion mentioned in another thread from contorting the actual frame and causing the suspension to foul during playback. I will open up the cutout to release all pressures on the actual speaker itself on this new box. From previous experience with CHR-70's in sealed enclosures I think I'll be pretty happy the way it all comes together. Now my only question is, what flavor of veneer should this gray coned driver be treated to?
Thanks for the input guys. Also, Buzz, what variation of enclosure are you on now and what was your favorite so far?
An anecdote: I like using brass screws. Chris does not. He says it is too easy to twist the heads off. My attitude is that i've twisted a head off i've tightened them too much (ornot done the pilot hole well enuff)
dave
Why bother with the soft brass screws when the supplied MA screws are so easy to use?
jeff
Because they are magnetic and every time i use the MA ones i'm swearing at them.
Now some stainless Torx (or hex) would be nice.
dave
Lots of "sheet metal" styles available in 18-8 stainless. You can even get them coated black.
McMaster-Carr
If you want Torx, the only one I could find is for plastic. There are more with the "tamper proof" style head, but I doubt you would want those.
jeff
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