Having mated the Mapletree Ultra 4se with a Decware se84b, has been very fine. Both are such good products. Both have a rightness. Neither hypes harmonics for an overly detailed upper treble. Both are detailed in the midrange and bass, taught in the bass. Both are quick at all frequencies, making for a coherent whole sound. With the Decware amp, I prefer the Mapletree to three other preamps I've had in the past 6 months; the others were a AVA T-6, a Audible Illusions Modulus 3, and even Decware's ZTPRE. Though each of those preamps had their virtues, the Mapletree Ultra 4se has the most virtues: namely, it is the cleanest, sweetest, quickest. It is the least "hi-fi" sounding, so is self efacing. Tube rolling can be cheap with this preamp because the NOS tubes that it uses are not the most in demand, but are plentiful.
~tom