I am using a four channel digital interface. There is a stereo balanced volume control with a PGA4311. The unit sounds great now. A little power has been done on the power supply.
Looking inside, the four channels and headphone circuit all use a MC33179 quad opamp. These are 36 cent four channel opamps.
Looking, there are small ceramic bypasses at the power pins. The design appears competent enough to upgrade to a faster, higher bandwidth, lower distortion chip.
I ordered some OPA4132 and LME49740 chips yesterday. I hate to do too much boardwork with these SOIC-14 chips. The 4132 are close enough in BW and slew rate that they are no issue. The LME49740 is another animal. I worry about using a chip with 11 times higher BW.
The four channels are balanced, and two are subwoofer out and the other two everything else. My thoughts are to use the LME49740 for the 60 Hz and up and either the MC33179 or OPA4132 for sub. J never use the headphone and the stock chip is higher current for a heavy load.
Should I just stick the OPA in to avoid an issue with a screamer. Or if locally decoupled well enough, is the LME enough of an upgrade to gamble?
George
Looking inside, the four channels and headphone circuit all use a MC33179 quad opamp. These are 36 cent four channel opamps.
Looking, there are small ceramic bypasses at the power pins. The design appears competent enough to upgrade to a faster, higher bandwidth, lower distortion chip.
I ordered some OPA4132 and LME49740 chips yesterday. I hate to do too much boardwork with these SOIC-14 chips. The 4132 are close enough in BW and slew rate that they are no issue. The LME49740 is another animal. I worry about using a chip with 11 times higher BW.
The four channels are balanced, and two are subwoofer out and the other two everything else. My thoughts are to use the LME49740 for the 60 Hz and up and either the MC33179 or OPA4132 for sub. J never use the headphone and the stock chip is higher current for a heavy load.
Should I just stick the OPA in to avoid an issue with a screamer. Or if locally decoupled well enough, is the LME enough of an upgrade to gamble?
George