Brief description of project
I am working on a device that has two audio signals. We have set up the board so that there are two audio out jacks. On the right jack the tip is sig#1 and the ring is #2. It is switched on the other, the left jack the tip is sig#2 and the ring is #1. We did this because we often use Radio Shack's external speaker which takes mono input from the tip. This way we could plug in two speakers and hear the one signal on one speaker and one on the other. Both audio out jacks have the other signal on the ring so that we can send both signals to a mic-in port on a computer and see both signals.
Also, there are two switches / thumbwheel potentiometers. Both switches power all of the board's ICs. The right pot controls the gain of the right signal (#1) and vis versa for the left.
Issue
I have realized a problem I could use some help solving:
1. When both switches are on, I am observing the audio crossing-over (hearing both signals on the external mono-input speaker) in one instance but not another. It is working well when I have the right audio jack connected, there is no combining of the signals on the external speaker. When I tried this with the left audio jack connected, I heard with both signals. These two tests were done with both switches on, pots turned up all the way.
Update: I found that when I connect an audio cable to the right jack (with other end is connected to nothing), the crossover issue of hearing sig#1 and sig#2 (heard on the external speaker with the left jack providing the signal) goes away. The right jack has a tip switch, so that the onboard 8ohm speaker outputs the signal#1 when the the right audio jack is not populated and when this jack is populated, signal to the lm386 (8ohm speaker amp) is disconnected.
I have attached a picture of the schematic and the board layout.
I am working on a device that has two audio signals. We have set up the board so that there are two audio out jacks. On the right jack the tip is sig#1 and the ring is #2. It is switched on the other, the left jack the tip is sig#2 and the ring is #1. We did this because we often use Radio Shack's external speaker which takes mono input from the tip. This way we could plug in two speakers and hear the one signal on one speaker and one on the other. Both audio out jacks have the other signal on the ring so that we can send both signals to a mic-in port on a computer and see both signals.
Also, there are two switches / thumbwheel potentiometers. Both switches power all of the board's ICs. The right pot controls the gain of the right signal (#1) and vis versa for the left.
Issue
I have realized a problem I could use some help solving:
1. When both switches are on, I am observing the audio crossing-over (hearing both signals on the external mono-input speaker) in one instance but not another. It is working well when I have the right audio jack connected, there is no combining of the signals on the external speaker. When I tried this with the left audio jack connected, I heard with both signals. These two tests were done with both switches on, pots turned up all the way.
Update: I found that when I connect an audio cable to the right jack (with other end is connected to nothing), the crossover issue of hearing sig#1 and sig#2 (heard on the external speaker with the left jack providing the signal) goes away. The right jack has a tip switch, so that the onboard 8ohm speaker outputs the signal#1 when the the right audio jack is not populated and when this jack is populated, signal to the lm386 (8ohm speaker amp) is disconnected.
I have attached a picture of the schematic and the board layout.
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