Most amps have passive EQ, which is the vintage way, but some amps use active EQ in a way that lets them get a broader array of tones including great vintage tones. My experience is with my 22 yr. old X100B. What other amps have active EQ? Don't the 5 band EQ Mesas? Don't some Matchless amps? Let me know which ones and I'll add it to this first post as a list. Another question. You might ask if the active EQ is pre or post overdrive, like the X100B is pre overdrive. No Clue about the others. List: Carvin: X100B Genz Benz: El Diablo Kingdom Amps: Neuma Standard Matchless: ??? Mesa Boogie: DC-3, DC-5 Mark II, III, IV - those with 5 band EQ ?? Peavey: JSX Rockmaster Preamp Stealth GT50 Ultra XXX Rivera: Chubster Sound City Mark II, III, IV VHT: ones with 5 band EQ??