Sinmarc is a Spanish amplifier and audio equipment manufacturer founded in 1966 in Barcelona. In an era when imported American gear was difficult to obtain in Spain, the company built its reputation on hand-wired, point-to-point tube amplifiers that took cues from the most popular Fender designs of the period. Models such as the G45 Rever, the MR-2120-C, and the 2160 are widely understood to be Spanish-built interpretations of Fender circuits like the Pro Reverb and Twin Reverb, executed with the components available to Barcelona builders at the time.

Beyond guitar amplifiers, Sinmarc produced a broader range of stage and studio equipment including bass amps, 2x12 and 4x12 cabinets, valve mixers, and self-powered PA mixers — examples include the SE-212V, the B 2280 C bass combo, the SP-6125R powered mixer, and the CM-1221. The shift toward solid-state circuitry and large-scale Asian manufacturing in the 1980s reduced the company's prominence, but its 1960s and 1970s tube-era output is now sought after on the European vintage market and is documented in the Spanish music documentary Sonido mosca (2019), which covers the brand's role in the Barcelona rock scene alongside groups like Los Salvajes.

Sinmarc has 4 products cataloged on Equipboard, including Combo Guitar Amplifiers and Guitar Amplifier Heads. Their gear is featured by 1 artist, with the strongest followings in Rock, Pop, and Orchestra. Notable users include Toni Torres.