What's the limiting factor, phones or head amp?

Hi,

I recently upgraded the Modi Multibit in my chain Schiit Modi Multibit -> Lake People G103-S -> HD6xx to a Chord Qutest and I'm having a very hard time telling much of a difference between the two DACs.

When I compare Modi Multibit and Qutest in my speaker system I can easily make out differences like better texture, better depth, easier flow...
But all these improvements are a mere shadow when listening with headphones.

Now I'm wondering what I should upgrade in order to get the most out of the Qutest?
The HD6xx are said to scale pretty well and the Lake People amp got a favorable review from Stereophile as being a pretty neutral amp only lacking slightly in the highs.

 

My experience with (the relatively inexpensive) Lake People amps, the G109A in my case, is that they're a bit bland and overly restricted, though very, very "clean" sounding as a consequence. The Sennheiser HD6XX (which I've not heard but is apparently a reskinned HD650, which I have had at home for a long while and isn't all that different from the HD600 I own now) isn't exactly TOTL due to weak bass quality, lack of incisiveness (not in the context of FR) and smallish headstage, but is really damn good at sussing out tiny nuances in recordings.

Also, this seems a more relevant post for the all-purpose advice thread than a standalone one. Then again, I suppose it's a valid question for many whether their headamps are doing their headphones justice or vise-versa.

https://superbestaudiofriends.org/i...purpose-advice-thread.19/page-427#post-278203

More relevant, many people on here agree that speakers are far more revealing of upstream components than any headphones are, esp. where imaging and staging are concerned; I wouldn't know anything much about that because I have no meaningful experience with 2ch or other besides some cheapish nearfields.