TubeMagic D1 - Enough to drive Ortho's?

I've not quite gotten into understanding impedence and power and stuff, but i spontaneously decided to order a Maverick Audio TubeMagic D1, should be turning up soon.

I've got HifiMan HE-5LE's, the specs of which are:

• Sensitivity: 87.5 dB, 1 mW
• Impedance: 38 Ohms

As for the Amp/DAC, the spec's are:

Maximum output power:   1000mW x 2 (32 ohms), 500mW x 2 (300 ohms), 300mW x 2 (600 ohms)

I've upgraded from a FiiO E9, which is rated as 1000mw, but i don't know if that's split between the 2 channels or per channel.

Anyway, what do the experts think? and are there any resources to help me understand impedence, and mW relation?

Well i got the unit today and i must say i'm very impressed, it's very well made and just feels top quality, looks amazing too, and the sound is an improvement over the FiiO E7/E9, just has alot more depth to it and richer.

Order despatched on friday in china and turned up this afternoon in UK, very fast shipping and only cost $20.

Unit itself worked out at about £132, absolute bargain, and UK government didn't get a penny in tax, i'm well pleased.