Pass Labs Integrated Amplifiers

Audiophiles, serious Audiophiles, have not considered an integrated amplifier as worthy product for 30+ years. Pass Labs has changed this paradigm, forever!

• Operational Points optimized for higher wattage requirements
• Greater Versatility
• Stable into any conceivable load
• Spectacular with difficult loads.

INT-25

At Pass Labs they build Fet amplifiers with excessive output stages, huge heat sinks and massive power supplies. They use the highest quality components in simple linear topologies, assembled and tested with care and subtlety. They measure well, sound great, and are reliable. Twenty plus years of ongoing innovation have kept the X and XA amplifiers at the forefront of high-end audio.

The INT-25 embodies all this and less. A smaller stereo Class-A amplifier at a lower price, it takes advantage of the lower power requirements to have simpler single-ended circuitry and fewer parts in the signal path. This also allows elimination of degeneration, “that other negative feedback” in all stages.

Simpler and fewer gain stages improves speed and stability. Lower voltages means the ability to run gain devices at higher bias currents, more deeply into Class-A. Newer power Fet technology replaces banks of parallel small transistors with a single pair of industrial devices, each having a 700 watt / 40 amp rating. With no current-hogging issues and a new constant-current bias circuit to compensate for temperature drift, they connect directly to the loudspeaker without ballast resistors for lowest possible distortion and highest damping factor. No degeneration also increases the efficiency and Class-A operating current, allowing greater Class A operation into low impedance and reactive loads.

The simple front end circuit uses two pairs of Pass Labs favourite NOS complementary Fets in common-source mode in a current feedback (CFA) configuration. 

The preamp section is a simplified single-ended version of the one used in the INT-60 and INT-250 with three line level inputs and no line level output.

Everything done in the signal chain from the microphone to the loudspeaker, forever leaves an indelible mark on the music. 

As with all Pass amplifiers, the technology and construction are strictly in the service of the listening experience. The INT-25 measures superbly, but its subjective qualities are most special. In an industry where products with great specs are often found to be dry and boring, this amplifier breathes new life into the music.

INT-60

The new INT-60 builds on the point 8 series power supply and output stages. It uses the same efficient toroidal design in the power supply with both an electrostatic and Mu-metal shield along with vacuum impregnating and epoxy fi ll. This gives you a very quiet transformer both electrically and mechanically. The power supply circuitry itself is also lower noise and has additional filtering, a little more complicated but worth it.

The INT-60 uses a simplified preamp and volume control circuit that gives you sixty three 1 dB steps with lower noise and distortion while removing some signal path parts.

INT-250

The new INT-250 builds on the point 8 series power supply and output stages. It uses the same efficient toroidal design in the power supply with both an electrostatic and Mu-metal shield along with vacuum impregnating and epoxy fill. This gives them a very quiet transformer both electrically and mechanically. The power supply circuitry itself is also lower noise and has additional filtering, a little more complicated but worth it. 

The INT-250 uses a simplified preamp and volume control circuit that gives you sixty three 1 dB steps with lower noise and distortion while removing some signal path parts. 

INT-25 Amplifier

INT-60 Amplifier

INT-250 Amplifier