I am mixing audio tones from two 555s.
The basic circuit is working fine so I have not shown all the little capacitors and resistors, etc.
I want to control the volume of 555 #1 only.
That is, I want to be able to set 555 #1 to 0 volume but still hear 555 #2.
I tried using a potentiometer as shown in the diagram. But if I set it to 0 resistance, all the current goes to ground and I cannot hear 555 #2.
I also tried using a large 256K pot at the output of 555 #1. This reduced the volume but the sound was still just audible.
Is there some way to isolate the two branches?
Is there some method with transistors?
Do I have to use two separate power sources?
What other options are there?