- Available as Head or 1×12 Combo
- 60/100 WATT combo
- ElectroVoice (EV) 12L speaker
- 5 Band EQ
- Pre-out/Power amp
- Slave out
The Mark II introduced channel footswitching, and wasn’t referred to as the Mark IIA until the Mark IIB was issued. It was also available as a head, which could be hooked up to a number of different speaker combinations, although a 1×12 cabinet was typical. However, the reverb circuit is considered noisy and the footswitching made a popping sound when used; both of these features were later improved on the Mark IIC. The preamp gain on the Mark IIs occurs after the tone controls and so, according to Mesa/Boogie, the IIA has a tighter, more focused sound than the Mark I.
The IIA and IIB, and some late-model Mark I amps, used a silicon device called fetron in place of one of the 12AX7 preamp tubes, and included a switch for configuring the amp for either fetron or 12AX7 operation. The reason for using a fetron was to address some of the problems associated with microphonic 12AX7 tubes in a high-gain situation; its use was later discontinued.