Mesa Boogie Mark IV "A" Version Combo - USA 1991

Here is a 1991 Mesa Boogie Mark IV 1x12” combo, an early “A” version of one of Mesa’s most versatile and highly regarded amplifiers. Compact in format but formidable in output, the Mark IV delivers 85 watts of all-tube power and an exceptionally wide tonal range, covering everything from pristine cleans to saturated, harmonically rich lead tones with ease.

This example features the sought-after “A” circuit (1990–1993), known for its rawer, more aggressive character, particularly in the lead channel, offering a grittier, more vintage-leaning response compared to the later “B” revisions. It has become a favourite among players who value punch, immediacy, and a more visceral feel under the fingers.

The triple-channel layout allows for seamless transitions between clean, rhythm, and lead sounds, supported by comprehensive footswitching options for real-time control. The onboard “Harmonics” function enhances sustain and overtone content, producing singing feedback and long, expressive note bloom when pushed.

Tone shaping is extensive and highly interactive, with independent pre-gain controls for each channel and a five-band post-gain graphic EQ. This allows for precise sculpting—from tight, articulate drive tones achieved by pushing treble in the gain stage and shaping with the EQ, through to heavier, more saturated textures by emphasising low and low-mid frequencies. The onboard spring reverb is lush and musical, complementing the amp’s depth and character.

Built with Mesa’s renowned robustness, this combo weighs approximately 37.6kg, reflecting its solid construction and powerful output. It comes fitted with its original caster wheels for easier transport and includes a Mesa Boogie protective cover.

Condition is superb, with minimal signs of wear. The tolex and grille cloth present exceptionally well, and all controls and functions operate exactly as intended.

Specifications:

Year: 1991
Country: USA
Model: Mesa Boogie Mark IV "A" Version
Finish: Black tolex
Power: 85 watts
Power Tubes: 4 × 6L6GC / 5881 / EL34
Preamp Tubes: Not specified
Speaker: 1 × 12" Electro-Voice Black Shadow (200 watt)
Channels: Three
Controls: Not specified
Serial Number: IV-008771
Accessories: Footswitch, amp cover