hi everyone,
since i started a thread on my hacked-up NS500V DVD/SACD player a while back, i figured i'd start one for the C222ES SACD changer i'm working on now.
here's my first round of tweaks:
- replaced stock power cord with old TG Audio cord i had lying around (basically 8 x 18ga speaker cable); re-wired R-core analog transformer directly into power cord, bypassing main power switch. this keeps the analog stages powered up at all times so i can get rid of the output muting transistors.
- DAC/Clock 3.3V supply decoupling cap changed from 47uF 25V Elna Silmic to 120uF 25V Pana HFQ - a whim change, but i may implement "Goudreau triplets" later which the HFQ is part of.
- changed front channel DAC output coupling caps from 47uF 25V Elna Silmic to Black Gate 10uF 50V nonpolar
- replaced stock JRC opamp with AD8620. one modder claimed the stock opamps sound better than the AD8620 here, but i have a hard time believing that. a big positive of the 8260 is that due to the better DC performance (JFET input vs bipolar for JRC), output DC offset is reduced from 30mV to a negligible .4mV, thus making the output coupling caps unnecessary. this is a big step forward in my opinion. the other modder did not remove the output coupling caps, instead replacing them with Black Gates... perhaps if you leave the caps in, you do not realize the full potential of the 8260 since coupling caps do not function as well with no DC offset.
- coupling cap/resistors/muting transistors after output stage bypassed entirely with a single 100 ohm Holco resistor wired directly to the output jacks
about to fire up the player, we'll see how it sounds with these small tweaks. next steps include a new clock circuit (Elso Kwak clock?) and supply tweaks.
cheers,
dorkus
since i started a thread on my hacked-up NS500V DVD/SACD player a while back, i figured i'd start one for the C222ES SACD changer i'm working on now.
here's my first round of tweaks:
- replaced stock power cord with old TG Audio cord i had lying around (basically 8 x 18ga speaker cable); re-wired R-core analog transformer directly into power cord, bypassing main power switch. this keeps the analog stages powered up at all times so i can get rid of the output muting transistors.
- DAC/Clock 3.3V supply decoupling cap changed from 47uF 25V Elna Silmic to 120uF 25V Pana HFQ - a whim change, but i may implement "Goudreau triplets" later which the HFQ is part of.
- changed front channel DAC output coupling caps from 47uF 25V Elna Silmic to Black Gate 10uF 50V nonpolar
- replaced stock JRC opamp with AD8620. one modder claimed the stock opamps sound better than the AD8620 here, but i have a hard time believing that. a big positive of the 8260 is that due to the better DC performance (JFET input vs bipolar for JRC), output DC offset is reduced from 30mV to a negligible .4mV, thus making the output coupling caps unnecessary. this is a big step forward in my opinion. the other modder did not remove the output coupling caps, instead replacing them with Black Gates... perhaps if you leave the caps in, you do not realize the full potential of the 8260 since coupling caps do not function as well with no DC offset.
- coupling cap/resistors/muting transistors after output stage bypassed entirely with a single 100 ohm Holco resistor wired directly to the output jacks
about to fire up the player, we'll see how it sounds with these small tweaks. next steps include a new clock circuit (Elso Kwak clock?) and supply tweaks.
cheers,
dorkus
clock frequency
11.2896MHz, as in schematic shown here:
http://www.diyaudio.com/forums/showthread.php?threadid=8462
11.2896MHz, as in schematic shown here:
http://www.diyaudio.com/forums/showthread.php?threadid=8462
so far, so good
after some break-in the player is sounding good with those small mods. definitely a bit more forward (was very "brash" initially but that's smoothing out with break-in), but with a lot more punch and energy... the sound is more "lively" now instead of "sleepy" as the old player tended to be. with this gain in energy there maybe some slight loss of warmth and mellowness, but i think that was more fuzz than anything else; it's much more transparent this way. i like the AD8260 a lot so far, it's sounding very good... still sounds like an opamp but much cleaner than any other opamp i've tried. not rich and euphonic, but a clean, sharply-defined sound. good thing i just got 3 more sample chips in the mail today!
SACD seems even more open and transparent now... listening to the Sony SACD of Stravinsky Firebird Suite (1960's recording w/Stravinsky conducting), there is more of that "live" quality, as if i'm one step closer to a live mic feed.of course there are dozen more steps to go, but it's still a noticable improvement. Redbook CD sounds better as well, in particular i notice that the soundstage has opened up and is huge now, altho still not as well-focused and distinct as the better CD players out there. it also lacks some bass fullness and macrodynamics compared to my modified MSB Link DAC, but compensates with better inner detail - individual instruments have a nice floating quality on the stage, with a well-developed sense of air around them. i think the NS500V dvd player with its AKM DAC chips could be even better still in this regard, but that player is a lot harder to mod cleanly.
i think the next big step will be power supply and clock upgrades... i am considering making the analog supply outboard, should be easy since it is quite separate from the main digital supply. i'm going to implement a version of the Kwak clock, but it'll take some time as i want to get an optimum surface-mount board layout. i think these two steps will greatly improve perceived dynamics and fullness of sound...
after some break-in the player is sounding good with those small mods. definitely a bit more forward (was very "brash" initially but that's smoothing out with break-in), but with a lot more punch and energy... the sound is more "lively" now instead of "sleepy" as the old player tended to be. with this gain in energy there maybe some slight loss of warmth and mellowness, but i think that was more fuzz than anything else; it's much more transparent this way. i like the AD8260 a lot so far, it's sounding very good... still sounds like an opamp but much cleaner than any other opamp i've tried. not rich and euphonic, but a clean, sharply-defined sound. good thing i just got 3 more sample chips in the mail today!
SACD seems even more open and transparent now... listening to the Sony SACD of Stravinsky Firebird Suite (1960's recording w/Stravinsky conducting), there is more of that "live" quality, as if i'm one step closer to a live mic feed.of course there are dozen more steps to go, but it's still a noticable improvement. Redbook CD sounds better as well, in particular i notice that the soundstage has opened up and is huge now, altho still not as well-focused and distinct as the better CD players out there. it also lacks some bass fullness and macrodynamics compared to my modified MSB Link DAC, but compensates with better inner detail - individual instruments have a nice floating quality on the stage, with a well-developed sense of air around them. i think the NS500V dvd player with its AKM DAC chips could be even better still in this regard, but that player is a lot harder to mod cleanly.
i think the next big step will be power supply and clock upgrades... i am considering making the analog supply outboard, should be easy since it is quite separate from the main digital supply. i'm going to implement a version of the Kwak clock, but it'll take some time as i want to get an optimum surface-mount board layout. i think these two steps will greatly improve perceived dynamics and fullness of sound...
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