Pass Labs INT-25 Integrated Amplifier

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 our favorite 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. The XA25 amplifier section is direct coupled requiring no DC servos or frequency compensation, neither adding too or subtracting from the experience.

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.

Specifications

Class = A (Integrated)

Inputs = Three (3) RCA

Remote = Yes

Gain = 26 dB gain

Output Power = 25 Watts rms @ 8 ohms / 50 Watts rms @ 4 ohms

Distortion = 0.1% @ 25 Watts, 8 ohms, 1 KHz

Class A Envelope = 50 Watt peak for 2, 4 or 8 ohm load

Bandwidth = DC to -2 dB @ 100 KHz

Noise = Less than 150 uV output, unweighted 20 to 20 KHz

Damping Factor = 500

Slew rate = 100 V/uS

Input Impedance = 48 Kohm

Peak Current = 10 Amp output (200 Watt peak into 2 ohms)

Protection = Shutdown at 10 amps output

Idle Power draw = 2.3 Amps @ 120 VAC (275 Watts)

Dimensions = 17″ W x 17.9″ D x 6″ H

Weight = 51 lbs

Shipping Weight = 56 lbs