Op-amped lampucera problem

defec

Member
2004-07-22 10:07 pm
!
Hi, I took my cheap CS4397 board, aka the Lampucera, and followed the below directions but also adding a .1uf ceramitic cap between pins 4 and 8 of the LM4562.

opamped_lampucera

Only now I'm getting -1.5 volts DC at the outputs. About half that at the opamp itself before the 1k/14.7 k resistor. I'm assuming this can be a problem. Is it okay to take the 14.7k resistor and move it from pin 4 to pin 8 of the opamp to cancel out the dc offset? Does anyone have any idea what else could be adjusted to get it zeroed if needed? Thanks.
 
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defec

Member
2004-07-22 10:07 pm
!
Okay, I swapped over the 14.7k resistor from the negative to the positive rail and now it's DC offset is less than a millivolt on one channel and 3ish on the other. All I had were some carbon film resistors around.

Anyway, It sounds much better now then when I tried it in it's stock configuration or just having the CS4397 output's going to caps as suggested on the lampucera site.