7.1 has mono surround backs, therefore, it is nothing more than 6.1 through 7 speakers. I know 7.1 refers to the number of speakers and not the number of channels, but that flies in the face of traditional surround nomenclature. By the same logic DPL would be a 5.1 system - we all know it isn't. Anyway, what's to stop you having 7.1 off a 6.1 amp by buying a speaker switch from RS for about £13 and delivering the 6th channel to 2 speakers?. Okay, it wouldn't sound as good as a proper 7.1 amp and a 7.1 amp would doubtless have more advanced facilities and upgradeability, but you would save a whole lot of money which you could put towards more frequent amp upgrades as technology advances. Many 6.1 amps have 100w or thereabouts for the 6th channel and so I'm sure 50W per speaker would be enough for the 6th and 7th channels in a 7.1 system. Has anyone tried this? I realise that you can achieve the same thing by hooking the 6th and 7th channels from a 7.1 output up to a stereo power amp, but power amps tend to cost more than £13!