Personally i use a sony pmc-m10 behing a field mixer (mini jack line in).
The Marantz PMD661MKII seems to fit the bill too (XLR line in).
[details=zoom rant]I never understood the industrial choice behind the Zoom H4N inputs, and its a pain to explain to every h4n owner i meet the differences between mic, instr, and line input, and why in impedance hell sometimes it will record a mixer line out and sometimes it will be distorted no matter what. For that mere reason, i stay away from their entire line of products.
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The family of portable recorders has greatly expanded those last three years, so you might need some time to think about your precise needs and use cases to make a choice. There is a whole Tascam lineof products that do 4 tracks under 500$.
My personnal buying “strategy” is to go for the under-200€ options, and/or save for some time and buy the over-1000/2000 € one. That’s the leap i think one needs to take for a significantly better sounding product nowadays.
Just out of curiosity, what field mixer is it ? (that “strange XLR”, wouldn’t it be a Tüchel ?)
(ps. i just realized the pcm-m10 has been discontinued :(((( )