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Opus Analog Power (5V) upgraded with Placid Single - Local 5v regulator bypassed - Placid is set at 5V, and it is fed by LCDPS at 9V (this is an overkill, but the second half of LCDPS was used to power the analog side and now sits idle. In addition, dropping the voltage to 3-4V above Placid's regulated output helps keep the transistors running cool. Power More discussion here: http://www.twistedpearau....aspx?g=posts&m=4558OPUS+Power supplies Power line directly from Placid I cut the trace from the local regulator output and soldered the power line from Placid to L2 Edited by user Saturday, November 28, 2009 11:22:16 AM(UTC)
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Joined: 10/5/2009(UTC) Posts: 15 Location: Sweden
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Nice work!
Does bypassing the onboard regulator improve the sound quality?
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Rank: Member
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Joined: 11/9/2007(UTC) Posts: 453 Location: usa
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I'm on the technical camp of the audiophiles, still I feel there is improvement with respect to low level details -sort of like more refined or more delicate. Can't do A/B comparison, so mostly from memory on familiar music.
Some e-mails with Wolfson engineers indicate that ultimately the performance of the DAC depends on the analog supply. But assuming the local regulator has 100 uV of noise and the Placid has 100 nV of noise, in theory, you can't hear that difference riding on signal that is at least 1000X higher than the noise. But kike most audio diy/tweakers like us, the feeling of having improved the system adds to the enjoyment of the music.
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Joined: 6/30/2008(UTC) Posts: 12 Location: South Worcestershire, UK
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1000X larger is only 60dB; this is only cassette or AM radio type dynamic range, and should be readily audible.
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Rank: Member
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Joined: 11/9/2007(UTC) Posts: 453 Location: usa
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That is true. But my ears only have 50 db dynamic range :-)
I did a volume test on my ears and with as loud a sound as I could stand set as reference zero, I couldn't hear pass -50 dB
Now, the noise of the lm317 is -60db, the Placid is probably -90db....
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Another picture, everything mounted, a little shielding...
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Rank: Member
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Joined: 11/9/2007(UTC) Posts: 453 Location: usa
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And operational...
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Rank: Member
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Joined: 10/5/2009(UTC) Posts: 15 Location: Sweden
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Hey glt,
Did you cut the trace before or after C18?
Daniel
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Joined: 11/9/2007(UTC) Posts: 453 Location: usa
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Before c18. Just right after the output of the local reg. Thus the c18 is still being used, which should be no problem for Placid. I wanted to do the cutting where there is more space. I try to make the mods reversible whenever possible. Good luck
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Joined: 10/5/2009(UTC) Posts: 15 Location: Sweden
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Helpful as always, thank you! This is the last mod before programming the Arduino and TFT display.
Daniel
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Rank: Member
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Joined: 11/9/2007(UTC) Posts: 453 Location: usa
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My OPUS configuration, New Year Edition :-)
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