Hello there,
i am currently working on a simple DSP guitar/line effect pedal,
using Paul's Teensy Audio Adaptor (SGTL5000).
I've built a schematic for the input/output pre-amp section, but i am not sure about the input/output levels of the audio adaptor board.
Are the line inputs bipolar? I mean are they centered (+/-) around 0V?
I've read in the datasheet that the input of the SGTL5000 can accept voltages between ~0V and ~3V.
So is this not true anymore for the audio adaptor shield when using the Line input? I mean line signals are usually bipolar +/- around 0V, right? So I would have levels from ~ -1.2V to 1.2V.
I don't want to damage the audio adaptor. Can i put in signals with -1.2V?
Here is a picture of the schematic:
http://i.imgur.com/DiNH3km.png
there you can see that right before going into the ADC of the SGTL5000, i remove the DC bias.
Please also comment on the schematic: Will it work this way, is it designed in a stupid way? (it's my first "not super small" circuit actually) If you're wondering about the thing in the lower left corner: Its two opamps buffering a voltage divider and providing double the output current to power the Virtual GND of the other opamps. Found something like this in a forum somewhere...
Thanks a lot for replying! If it's possible for you to reply even today, I would really appreciate this,
because i am very short in time and I try to build this circuit in a few hours. Yeah, sorry...
Anyway, I will be very happy to read any answers,
Best regards, Jan
i am currently working on a simple DSP guitar/line effect pedal,
using Paul's Teensy Audio Adaptor (SGTL5000).
I've built a schematic for the input/output pre-amp section, but i am not sure about the input/output levels of the audio adaptor board.
Are the line inputs bipolar? I mean are they centered (+/-) around 0V?
I've read in the datasheet that the input of the SGTL5000 can accept voltages between ~0V and ~3V.
So is this not true anymore for the audio adaptor shield when using the Line input? I mean line signals are usually bipolar +/- around 0V, right? So I would have levels from ~ -1.2V to 1.2V.
I don't want to damage the audio adaptor. Can i put in signals with -1.2V?
Here is a picture of the schematic:
http://i.imgur.com/DiNH3km.png
there you can see that right before going into the ADC of the SGTL5000, i remove the DC bias.
Please also comment on the schematic: Will it work this way, is it designed in a stupid way? (it's my first "not super small" circuit actually) If you're wondering about the thing in the lower left corner: Its two opamps buffering a voltage divider and providing double the output current to power the Virtual GND of the other opamps. Found something like this in a forum somewhere...
Thanks a lot for replying! If it's possible for you to reply even today, I would really appreciate this,
because i am very short in time and I try to build this circuit in a few hours. Yeah, sorry...
Anyway, I will be very happy to read any answers,
Best regards, Jan
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