symon,
lpf = low pass filter
surprisingly, there was no decoupling cap for the opamp.
what's more surprising is that the TDA1541 DAC also has no decoupling cap!
Only an electrolytic (Nichicon MUSE) was used to bypass the psu.
i don't know what the heck Sony was thingking.
baka di pa uso yun psu decoupling nun panahon nito.