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Post by garbulky on Sept 11, 2018 20:21:51 GMT -5
With all due respect to everyone here I’ve been working with and or designing both linear and switching supplies for more then 25 years. While linear supplies are simple and easy to do they have one huge disadvantage. 60 and 120Hz noise that you can’t get around. It modulates both on the ground planes and the power lines even with all the secondary filtering and storage. Modern day switchers are running up in the megahertz range so second, third and even forth harmonics are way outside the audio band and therefore offer a huge increase in S/N due to the reduced noise floor. It is for this exact reason why we are using them in all new designs. They simply offer better audio performance. Lonnie Pardon me, but do they really? Two different publications have measured the Emotiva XPA gen 3 units with their switching power supplies. This is THX's measurements of the XPA gen 3 with comparison to the Monlith 7 channel (torroid) . We are seeing -40 db harmonics with the XPA gen 3 and -108 db with the Monlith amp. . Jeez look at this IMD test from the XPA gen 3 _pid-31_cid-48_tid-34_20180322_223435_w.png) In comparison is the Monolith 7 channel IMD test _pid-22_cid-48_tid-34_20180321_181950_w.png) In the Monolith in the -3db test the first distortion spike is about -105 db. In the Emotiva you get a --38 db spike with lots of spikes close to it. That's a large difference and likely pretty audible. Here's Stereophile's test of the XPA- gen 3 - pretty similar.  |
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Post by novisnick on Sept 21, 2018 6:29:21 GMT -5
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Post by rbk123 on Sept 21, 2018 7:58:24 GMT -5
It looks like my Geek needs a 12v power supply. I have a message in to LH Labs to confirm specs, and if I hear what I think I will from them - I will order the ifi iPower 12v power supply and try it. Did you get it? |
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klinemj
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Official Emofest Scribe
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Post by klinemj on Sept 21, 2018 8:10:54 GMT -5
It looks like my Geek needs a 12v power supply. I have a message in to LH Labs to confirm specs, and if I hear what I think I will from them - I will order the ifi iPower 12v power supply and try it. Did you get it? yes...sounds great. Have not had time to do extensive comparisons to the original but it seems quieter. Mark |
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