Active vs Passive Hi Pass Filter for Audio

[AltAudio]

Integrating 5KΩ Variable Resistor

Trying to add on/off switch to this circuit, but it ends up sapping the 9V batteries of voltage. I added the switch between LED and transformer stages.

 

[audioguru]

Trying to add on/off switch to this circuit, but it ends up sapping the 9V batteries of voltage. I added the switch between LED and transformer stages.

You somehow connected the transformer to the positive supply and now you added a switch to disconnect something.
Please post a schematic of the existing circuit so we know what you are talking about.

 

[AltAudio]

Will do later today, thanks.

 

[AltAudio]

Ok, here are two schematics: HiPass is the one that works but has not potentiometer. HiPass2 is the attempt to add pot. Incidentally, I had to improvise a bit with regard to symbols as I could not find a pot in LT Spice. The attempts I made with pot failed miserably at the point of connecting output to transformer.

 

[audioguru]

What are you doing, AltAudio?
1) You have two positive 9V batteries in parallel, not in series. So there is no negative supply for the opamps.
2) Your attempt at connecting the transformer primary to +9V simply shorts the positive battery.
3) A volume control connects to the input of a power amplifier, not to its output.

A pot is simply two resistors in series.

Your circuit has a voltage gain of more than 1160 times which is way too much gain, no wonder you need a volume control.

 

[AltAudio]

Ok, I forgot to remove the ground and 47Ω components. This is how it looks currently.

 

[audioguru]

You don't know what you are doing:
1) The 47 ohm resistor is important for the LED to survive.
2) The connection of the transformer primary to V+ does absolutely nothing. Connect it to ground instead like I showed before.
3) The voltage gain is much too high at more than 1160 times. What is the input coming from? A very weak microphone?