My Vali 1.0 died which I've been using with Drop/Senn HD58X headphones and Modi MB. My other amp is a Liquid Spark and my other phones are AQ...
From what I've read about the Schiit Vidar might combine warmth and detail. Or how about anything Nelson Pass has designed.
There is the Hagerman Tuba. https://hagerman-audio-labs.myshopify.com/products/tuba-vacuum-tube-headphone-amplifier
The Little Dot MkIII is also in your price range. https://www.amazon.com/Little-MK-III-Headphone-Amplifier/dp/B00CHIKIDM
I've got the HD58X and like the Monolith Liquid Spark (no dac) for $100 and the ifi nano idsd le for $140....
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