Coming from Fostex/Denon biodyna's being my headphones of choice I went on a bit of an amp journey to find a great pairing for them and the Ember & Polaris is where I've ended and am fully satisfied with no need for searching out any other amps. Meier Corda JAZZ-ff and modded Gustard H10 were the previous amps. The Polaris is bit better all around than and less than half the size of an H10...absolutey lovely low end/subbase presence with little more forward mids/vocals. The JAZ-ff was not a good pairing at all for biodyna's...low end lacked presence and didn't sound lively, had a more flat & cold presentation.

Very much satisfied with the Garage 1217 amps - if you want a warm & lively sound from a biodyna driver they are a great way to go. The Ember II with either a Reflector 6H23P-EB or Sovtek 6H30P-EB tube is setup I like best overall for pairing with a biodyna, when I really want that ultimate subbass presentation and lively/punchy experience (at some expense of instrument separation, 3D spacial presence, and vocal presentation) I like running the Polaris. Both pair well with Sennheiser HD6XX series and the more lively sounding planar magnetics, like a Gold Planar GL2000 or certain HiFiMans, as well.