ES2
K701
My hornet is not "M". It drives the 701 but it is just too in my face for this phone for me. I prefer the Meir Headfi amp or preamp Pat 5 (refurbished) brings out the beauty of this beast.
It is perfect at low volume-Low Gain for the ES2, UM1 and UM2. I think it gives alot of body and slam to the Koss 75's in the middle gain setting verses an unamped comparison.