MP1 Mk. 3.3

About the MP1 Mk. 3.3

The Atma-Sphere MP-1 Mk. 3.3 is a world-class, fully differential and balanced vacuum tube preamplifier that supports the Balanced Line standard (AES48), eliminating interconnect cable coloration and noise. It features a patented direct-coupled Circlotronic® output stage with zero feedback and dual-mono construction, providing wide bandwidth, low distortion, and dynamic range. The phono section offers approximately 66 dB gain with RIAA accuracy within 0.07 dB and supports very low output moving coil cartridges. The line stage gain is 12 dB with a frequency response from 0.1 Hz to 400 kHz. The unit includes precision 24-position stepped volume control built from a Shallco® custom switch, Teflon® custom coupling capacitors, and low-noise star grounding. The power supply is fully regulated and isolated in a separate chassis. The MP-1 Mk. 3.3 is capable of driving 32-ohm headphones and includes XLR connectors for balanced inputs and outputs, with optional RCA inputs and outputs. It weighs 42 lbs per chassis and measures 13" deep x 17" wide x 5.5" tall per chassis, with a 19" wide x 6" tall faceplate. The preamplifier requires a warm-up period of about 1-2 hours for optimal sound and comes with a three-year transferable warranty and one-year warranty on tubes.