Hello. My father (rash man) has asked my advice on headphone amps. (He has just invested in a pair of Sennheiser 580 'phones, a steal at £80). Now I'm very happy with my own headphone amp, which is a "Solo" Mk II from Graham Slee Projects, but one of the reasons why I'm happy with it is that I bought it for only £170 new, while the only-somewhat-updated Mk III version now sells for £375. It may well be worth it, but I feel he and I should be exploring alternatives too. So: what would people suggest as a headphone amp at (or preferably significantly less than) £400? I thought perhaps an Earmax - but would welcome any suggestions.