[Joelc87]

The Portable Micro is about the equivalent of the 06 Micro stack maybe slightly less SQ but almost negligable. Thus it retails for the same. In comparison to the 07 Micro Stack(the non-portable ones) the SQ in these is significantly better partly due to completely new components and class A biasing such. The Micro's have the same circuit designs as the Home modules and Home DACs(I think) I know the Amps are the same not sure about the DACs. The Ultra Micros use the same components as the Max Modules, but are almost twice as expensive. Please note that just because the new micros have essentially the same electronics as the Home and Max amps doesn't mean that they have equal sound quality. The Home and Max amps have significantly upgraded power supplies as well as fully decoupled dual mono signal paths on higher quality boards. The Micros are no slouches though trust me I have the new Micro and Micro DAC and they're an excellent pair.

Also while the Portable might have a slightly cleaner noise floor due to the battery power the Micro Stack is plenty clean and I don't really hear noise until the volume nob is at least twice as high as my ears could take, and that's with IEMs too...with the Grado's there is no noise.