i have a Metro Amp ' 68 Superlead ptp in my 1959 SLP(Sozo caps, MM OT/choke) that im thinking of changing to Superbass specs. i know the early ones just didnt have a bright cap. is it just a few value/resistor changes? a totally different tone stack? increase in power supply filtering? i was also going to switch out the JJ EL-34's for a quad of Shuguang/Valve Arts KT66. im running it though a 1960AX loaded with Scumback H55/75hz. i love that Band of Gypsies clean tone which is why i want to make the switch.