JJ ECC83MG with fully Balanced triodes. We recommend these for long tail phase inverter stages which are common in most push pull circuits (most all guitar amps), or anywhere that a tube with symmetrical sections is desired. The ECC83MG has a fair amount of harmonic density but remains very open sounding whether played clean or overdriven. Tonally it fits nicely between the JJ ECC83S and JJ ECC803S.