.... since headphones make it sound like the music is being played in your head, not out in front of you.

https://forum.allaboutcircuits.com/threads/project-stereo-cross-feed-network-for-headphones.125782/

Also recently I've completed an active circuit that does basically the same processing as the passive one (see the link). Both of them don't completely eliminate the sense of reproduction in the head, but in my opinion do make the reproduction apparently localized in the front.

 

Is there no ground wire between the AC plug and your circuit?

When you look at the negative power supply (which I think is the common or ground of your circuit), where is the scope's input ground connected?

I just went back and reviewed the thread. If you are getting 30V P-P at 60 Hz on "ground" and you are only using a single +15V supply, you are looking at the power line. Earthing ("grounding") is a very good idea for this and other reasons.

 

Is there no ground wire between the AC plug and your circuit?

When you look at the negative power supply (which I think is the common or ground of your circuit), where is the scope's input ground connected?

I just went back and reviewed the thread. If you are getting 30V P-P at 60 Hz on "ground" and you are only using a single +15V supply, you are looking at the power line. Earthing ("grounding") is a very good idea for this and other reasons.

Normally no, I don't have the ground wire from the AC plug connected to the circuit under test.

My bench power supply is variable dual +/- voltage output with respect to a common terminal. The way that the power supply was arranged, the common terminal is not connected to earth or the green wire coming from the AC wall outlet. The 'scope's input ground is connected to the common of the supply. In putting together the supply, I do have a binding post on the supply connected to earth, so I can connect common and earth terminals.

In testing the MOSFET follower, the drain was connected to +15V and the source terminal of the FET through the source resistor connected to the common terminal.

Today I noticed the same thing occurring when testing a different circuit. My 'scope is about 23 years old, so maybe something in the 'scope is failing.

Thanks for the help,
Pete

 

Was the ground lead of your scope probe connected to the common "ground" of your circuit?

 

Was the ground lead of your scope probe connected to the common "ground" of your circuit?

Yes.

This afternoon, while testing with a 'scope probe terminated in alligator clips, the ground alligator clip connected to common of the power supply, and common NOT earthed, I did not see the disturbance on the 'scope. So I might conclude that the tip probe that I used previously is defective. Not sure if a faulty tip probe could produce what I'm seeing where common of the power supply is not earthed, but does that seem like a reasonable possibility?

Thanks,
Pete

 

Yes, it is a possibility. It could be something simple like a poor connection between the ground lead and the clip -happens with my cheap probes and even the Tektronix probes sometimes.

 

Yes, it is a possibility. It could be something simple like a poor connection between the ground lead and the clip -happens with my cheap probes and even the Tektronix probes sometimes.

Thank you!