A.F. OUTPUT PENTODEEL34 II has fuller low mids and low end but does not lose headroom in the high end. Stronger than regular EL34 but not as aggressive as the E34L.
A.F. DOUBLE TRIODEECC82 is 12AU7 medium gain pre-amplifying double triode. Provides a very smooth sound with well-defined tones suitable for audio and guitar amplifiers.
R.F. DOUBLE TRIODEECC81 is 12AT7 medium gain pre-amplifying double triode. Can be also used as replacement for 12AX7 in many applications. Very smooth and warm sound. Very low microphonic. Good for phase inverters or reverb drivers.