Sennheiser HD6XX Headphones

[Chewie5150]

I'd ignore this. Audiophile forums want to run these headphones with tubes and not solid state. Tubes objectively measure worse than solid state and any benefits people think they hear are because of distortion, artifacts and change in the frequency response due to those amps.
I have a headphone amp too. They are no better or worse than the newer Apollo interfaces for driving HD650. I'd rather adjust the eq to flatten the response a bit (bump up the 2K, reduce the bass).

yes. I totally sense a lot of corksniffery out there on forums about this. I think I'm good with Apollo's HP outputs for the time being

 

[FPFL]

Yes, the idea that integrated circuits... are a problem?!?! is LOL funny.

 

[Smittefar]

Did you try running the headphones directly from the AxeFX? That HP amp is very powerful.