Bug #42
openCore 8 - Mic level is low
0%
Description
I connect the 2 pin header of MIC3 from the top board to the Bottom board (next to the speaker output)
and placed one of the DORSETTE Educational tapes to listed to AUDIO through the ATARI XC12 tape
i can hear the Audio / voice form the Tape but the level is significant low compared to a real Atari
Nir
Updated by sadosp over 7 years ago
Have you connect these with right polarity? I mean ground to ground etc?
Updated by foft over 7 years ago
I don't have any tapes! I've not tuned the volume but it seemed pretty loud to me...
Updated by ndary over 7 years ago
yes i connected correctly... and the volume still low..
i also notices that when the X12 is connected but nothing is played on the tape you can hear 'noise' from the MIC input
Nir
Updated by foft over 7 years ago
Yeah we need a digital filter for that, part of the reason I don't want to make it louder yet:-). I found it pretty load though when I connected an input.
Updated by sadosp over 7 years ago
Noise is there only when the SIO connector of XC12 is connected?
Updated by foft over 7 years ago
- Subject changed from Core 9 - Mic level is low to Core 8 - Mic level is low
Updated by ndary over 7 years ago
yes Panos, the noise is when SIO of the XC12 is connected
Updated by foft over 7 years ago
I think on the final board we should add a passive low pass filter to the ADC inputs. Also are large resistor to pull it down when there is no input connected. Then I can boost the volume without boosting the noise. Of course we can test this by adding some parts to this board...
Updated by foft over 3 years ago
This is due to the Atari audio 'mixing' circuit. It has a gain of 5.6x and doesn't really mix - just directly connected...