Hi Chris
Decided not to go with Ci as it is a pain to add on this PCB as double sided which makes resistor removal a pain. Could have cut the track under the PCB and add the cap there but I probably would have stuffed it. I'll live with the DC offset.
The LM3875 Brian Bell amp has a tube like sound to it which makes it sound smooth and glosses over the harsh parts of the music. Maybe it has high levels of even order harmonics. What's odd is it is quieter in the cheap plastic case with no noise at all except for a small pffftt on shutdown as the caps drain. Maybe the external power supply helps or the small 50VA transformer.
Off topic - FYI Chris
It's funny how things can snowball as experienced over the last couple of months. I built a small 0.1 woofer and needed a amp so tried a TPA3116 mono which turned out bad with noise and massive turn on thump.
So pulled out my ESP P19 and cut the PCB in half and used one half to drive the 0.1 woofer (see pic). That left me with the case and power supply so the LM1875 (ebay modules) went in there.
Now with the left over ESP P19 half I built another small 0.1 woofer and needed a case for it. Out came the LM3875 Brian Bell and installed the ESP P19 in there.
I thought that was the end of it as I was going to give away the LM3875 but remembered I still had a left over power supply case that powered the LM1875. So the LM3875 went in and is now a test amp.
Speaking of test amps. In the eBay module thread I mentioned I had buzzing issues when running 2 channels on the ESP P72 (LM1875) module. So cut it down to make a single channel and has become a small bench top amp (see pic).
Decided not to go with Ci as it is a pain to add on this PCB as double sided which makes resistor removal a pain. Could have cut the track under the PCB and add the cap there but I probably would have stuffed it. I'll live with the DC offset.
The LM3875 Brian Bell amp has a tube like sound to it which makes it sound smooth and glosses over the harsh parts of the music. Maybe it has high levels of even order harmonics. What's odd is it is quieter in the cheap plastic case with no noise at all except for a small pffftt on shutdown as the caps drain. Maybe the external power supply helps or the small 50VA transformer.
Off topic - FYI Chris
It's funny how things can snowball as experienced over the last couple of months. I built a small 0.1 woofer and needed a amp so tried a TPA3116 mono which turned out bad with noise and massive turn on thump.
So pulled out my ESP P19 and cut the PCB in half and used one half to drive the 0.1 woofer (see pic). That left me with the case and power supply so the LM1875 (ebay modules) went in there.
Now with the left over ESP P19 half I built another small 0.1 woofer and needed a case for it. Out came the LM3875 Brian Bell and installed the ESP P19 in there.
I thought that was the end of it as I was going to give away the LM3875 but remembered I still had a left over power supply case that powered the LM1875. So the LM3875 went in and is now a test amp.
Speaking of test amps. In the eBay module thread I mentioned I had buzzing issues when running 2 channels on the ESP P72 (LM1875) module. So cut it down to make a single channel and has become a small bench top amp (see pic).
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