Интегральные усилители — Primare I25

The I25 is a full-size modular integrated amplifier from Primare, the Swedish company based in Limhamn. In its current form it is an analogue-only platform, and Primare lists it at EUR 2,800. Owners who later want digital inputs or streaming can fit the DM36 DAC module and the SM35 Prisma network player module at any time, which turns the chassis into the I25 Prisma rather than requiring a new amplifier.

Key specs that matter

Output is 2 x 100 W into 8 ohm and 2 x 200 W into 4 ohm. Five stereo pairs of RCA line inputs are provided, each with an input impedance of 15 kohm, along with one RCA line output and one RCA preamp output, both at 100 ohm output impedance. Primare quotes a frequency response of 20 Hz to 20 kHz within 0.2 dB, THD plus noise below 0.01% at 10 W into 8 ohm across that band while noise sits more than 100 dB below the signal. Gain from an RCA input is 16.5 dB to the preamp output and 42.5 dB to the speaker terminals. The case measures 430 x 106 x 420 mm, weighs 11 kg, with titanium or black as the two finish options.

Engineering and use context

The I25 was among the first Primare amplifiers to use UFPD 2, a reworked version of the company's all-analogue Class D technology. Its error amplifier does not alter the gain versus frequency curve, so bandwidth need not be limited, and a custom output coil in the second-order filter gives feedback control across the whole audio band with low phase shift. A switch mode supply with active power factor correction feeds the module, using two PFC converters running 180 degrees out of phase in transition mode to cut current ripple and switching losses. Because a Class D module can carry its heat sink on the circuit board, the output devices connect directly to the speaker posts. Source selection uses relays in place of CMOS switching chips, while level is handled by a 2 x 4 channel balanced-mode volume IC. An OLED display developed for automotive use shows the settings.

Pairing

Each input can be renamed, hidden, given its own gain trim or set to fixed volume, so a surround processor can pass its front channels through the I25 at unity. The preamp output can drive a second power amplifier or a subwoofer. Control runs through the C25 infrared remote, an IR input and output, a 12 V trigger output and an RS232 port for home automation systems, and auto-sense can select whichever source becomes active.

Alternatives

The Primare I35 is the larger integrated model, rated at 150 W per channel and fed by a 600 W power supply.