Replacement Valve Kit for Mesa Boogie Simul-Class 2:Ninety (1 x ECC83 2 x Bal...
2 x Selected Premium Grade JJ Balanced ECC83 for the phase inverters in positions V2 and V3. Note: The balanced ECC83 preamp valves go in the V2 and V3 positions which are the preamp valves furthest from your input jack.