Dedicated headphone amp vs Headphone socket on amp

Ultimately, I am now going in the direction of choosing a new set of headphones. Given the strong performance level of the existing headphone socket in the Rega Aethos. A sensible option would be to build upon it. My overall preference is for open back type headphones providing the trademark open and wide soundstage in my current Sony MDR-F1. Now, as good as these headphones have been over the years, some areas of concern can not be overlooked. Becoming more apparent when comparing sound on my reference system with headphones and without. This is where the gulf in quality and of course price is crystal clear. The headphones just lack the warmth, resolution , depth in soundstage, timbre and separation of the reference system.

All things considered above, what might be some options to explore in a new set of headphones with a budget of $400 - $1000 ?.....Are there any standout performers / perennial favorites among seasoned headphones enthusiasts coming with strong recommendation.

Good choice. 

Some to think about... Sennheiser, Focal, and Grado. There are lots more available that are great. I have a large selection... and only use the Sennheiser... my partner has used Sennheiser for decades at night when I am sleeping.. She keeps them on all night and is extremely picky about comfort and she is female so is also sensitive to bad sound. 

I shut off the power amp in my main system and switch on a Schiit Vali 3 with a Loki EQ (my Freya preamp has 3 outputs). Great sounding combo that just sings. Around 300 bucks for this rig including the little Schiit cables between the Vali and the Loki. The Vali 3 has lots of voltage and drives my phones with the Grado extension cable with ease. Grado SR325X phones.

I’d highly recommend these Hifiman Arya Organics that can easily be returned through Amazon if they don’t work out.  I own the Arya Stealths that are a model below these and am thrilled with them, and the Organics are supposed to be a significant improvement (see review below) but aren’t much more expensive and still within your budget.  They are also relatively easy to drive so should work perfectly fine with your Aethos.  The Stealths are very open sounding with an expansive soundstage and imaging that is very much of an “outside the head” type of presentation.  They are neutral and very balanced with great detail and tone with very quick, tight, and tuneful bass and are very light and comfortable to wear for long periods of time.  They go quite low but don’t do boom boom kinda bass so if you listen to EDM, rap, etc. there are probably better choices, but if you want a well-balanced, audiophile experience these are excellent and very well worth a try.  Just one idea FWIW, and best of luck. 

https://www.amazon.com/HIFIMAN-Arya-Organic-Full-Size-Audiophiles/dp/B0C5RFXMM5/ref=sr_1_1?crid=63ME27D9XL7L&dib=eyJ2IjoiMSJ9.gZiIW-FtM_VJzkxpPNYXmtY9arIQ1GRqHWX_x5G3RMpKL12EiHBglMp-Gz0EdJ0SizCWbspiltGmMA8iGOxUuA99Ymomm_9u9ih29HMbim-cfPcFI5wr_A6ikbBbK5ZVZ5HtaqitghBfUa-HlTQXTJCSBWHfJMqqx6aYxAsR-zkA9wmRgi2lvnfN-2P5HKYGqzxSwzu5MhguvwF2v1IExq4TEP1eCK8ExrAPAxD34Ok.p540th1sN4ffFXXsj-V44PP0DMFJHoX6c3Oya9JWI60&dib_tag=se&keywords=hifiman+arya+organic&qid=1745004111&sprefix=Hifiman+arya%2Caps%2C107&sr=8-1

The review…

https://soundnews.net/reviews/headphones/hifiman-arya-organic-review-comparison/

The most difficult  factor to get from an headphone is a natural timbre...

On par with it the spatial qualities of sound, and with many good public recording an "out of the head" holographical effect when you forgot that you listen headphone  as if listening speakers.

None of my past 10  headphones ever  did this two aspects right together...

Add to this  very deep bass with no booming effect and we lost most headphone at any price...

The best  headphone for timbre i owned, save my AKG K340, was the Stax SR-5 gold, but the soundfield was around my head never out of my head and no deep bass at all...

I am not able to recommend any other headphone than my optimized K340 but it is old now...

I would fear buying anything new because of costs and dissatisfaction