Hi, i decided to get my first heaphone amp. I ordered this one http://www.audiologica.co.uk/grahamsleesolo.htmlgclid=CPODiPHgr7ICFYYNfAod3hcAVw - graham slee solo intro srg green mk 2. Site mentioned that it is new updated model. But later i discovered that there are two another models. Graham...