Tiamat 7.1 v2 on AVR Pre-Outs (analogue RCA outputs)

Hiya Brand new Tiamat owner, here. I'm going to be hooking this up to an AVR receiver's 7.1 pre-outs (line level RCA outputs) and was wondering ... Should I place cheap headphone amps between each input to the Tiamat, or will the level on the pre-outs be enough to send decent audio to the cans? It's an Integra DTR30.6 AVR, if that helps, and according to one of the manuals this is the "Rated RCA Output Level and Impedance" [INDENT]200 mV/470 Ω (PRE OUT, PRE/LINE OUT)[/INDENT] The reason why I ask is that the product itself states you can plug it straight into your motherboard outputs which I would assume have a similar (or less) powerful output. However, I have also read that this is basically the worst idea in the world. ;-) ANYWAY ... there's my question, apologies for the ramble! Best E PS - Did a bit of searching, and couldn't quite find an answer ... this one didn't help, unfortunately.