Op-amped lampucera problem

defec · 12:28 AM

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.

defec · 14th September 2010, 03:22 AM

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.

14th September 2010, 12:05 AM	#1
defec diyAudio Member Join Date: Jul 2004 Location: !	Op-amped lampucera problem 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. Last edited by defec; 14th September 2010 at 12:28 AM.

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14th September 2010, 03:22 AM	#2
defec diyAudio Member Join Date: Jul 2004 Location: !	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.

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