help with op amp headphone amp hum and distortion

[gregas]

So what do you think was the biggest contributor to reducing the hum?

 

[Rick PA Stadel]

From .. what point in the development?

Because -- a DC offset, for example, often masquerades as a hum problem.

Are you considering attacking the remaining hum after all?

 

[gregas]

Yes.
We moved where the input came from. No longer on the tube pin 1.
Also added an input and output cap.
I guess out of those mods.

At one point I may give it another go but not anytime soon.
I think you mentioned to seperate the rectifier and the smoothing caps?
Right now the headphone amp listened to on my Grados sounds better than the main amp and speakers.