After reading praises regarding the Phillips TDA 1451 DAC chip I purchased this Sony CD player. I liked its sound in stock condition but of course we are DIY. You may be interested in my upgrades.
-A/C power line filter with equipment ground added
-Gold plated RCA jacks installed
-All power supply capacitors changed to Nichicon UFG
-Rectifying diodes charged to Vishay Ultra Fast BYV26C
-DAC decoupling capacitors changed to Wima .100uf PPS
-Wima .022uf PPS bypass capacitors added to DAC power pins
-Output coupling capacitors changed to 3.3uf Clarity Cap ESA (sized for 20K ohm feed impedance)
-Removed muting and emphasis transistors
-Low pass op amp changed to Burr Brown OPA2134
-Resistors in analog circuit changed to PRP metal film
-A/C power line filter with equipment ground added
-Gold plated RCA jacks installed
-All power supply capacitors changed to Nichicon UFG
-Rectifying diodes charged to Vishay Ultra Fast BYV26C
-DAC decoupling capacitors changed to Wima .100uf PPS
-Wima .022uf PPS bypass capacitors added to DAC power pins
-Output coupling capacitors changed to 3.3uf Clarity Cap ESA (sized for 20K ohm feed impedance)
-Removed muting and emphasis transistors
-Low pass op amp changed to Burr Brown OPA2134
-Resistors in analog circuit changed to PRP metal film
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Nice to see work neatly done, particularly where oversized parts are used 
You might want to investigate using Jfet's for the muting if you find any clicks etc annoying. Often they can be a direct swap for bjt's as long as the control voltage is within suitable limits. Although a Jfet won't achieve as deep a mute as the bjt they are pretty good if used correctly and a suitable device chosen.
You might want to investigate using Jfet's for the muting if you find any clicks etc annoying. Often they can be a direct swap for bjt's as long as the control voltage is within suitable limits. Although a Jfet won't achieve as deep a mute as the bjt they are pretty good if used correctly and a suitable device chosen.
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