Paper Japan TR-07hp HeadPhone amplifier NEW October 23, 2014 Matej Isak Analog Squared Paper Japan TR-07hp (HeadPhone) amplifier prototype. S.I.T (V-FET) triode characteristic and what is seems most simple pure transistor amp.Class A006P Battery UseFull DiscreteNon NFB5~100KHzhttp://www.analog2p.com