Model 88

About the Model 88

The AudioPrism Audiopax Model 88 is a Brazilian high-end vacuum-tube power amplifier produced as a pair of monoblocks, with one amplifier assigned to each stereo channel. Introduced around 2001 and presented at CES in 2002, it uses an unconventional single-ended Class A1 pentode design with two KT88 output tubes per monoblock and a 12AT7 driver stage. Audiopax’s ASTAT (Asymmetrical Series-Twin Amplifier Topology) and PTS (Perfect Triode Simulation) concepts were intended to provide the tonal characteristics associated with low-power triode amplifiers while delivering substantially greater output power. The amplifier has no global negative feedback and includes the user-adjustable Timbre Lock system, which changes the KT88 bias settings to optimize the amplifier-to-speaker interface and subjective tonal balance. Each monoblock provides RCA line-level input and loudspeaker binding-post output. Published documentation differs slightly on frequency-response limits and physical dimensions; the original manual specifies 14 Hz–100 kHz, while several contemporary reviews and listings specify 14 Hz–90 kHz. The Model 88 is a historical product and is generally encountered on the used market rather than as a current production model.