Integrated amplifiers — Allnic Audio T-1500 mk2

The Allnic Audio T-1500 mk2 is a stereo integrated amplifier using single-ended 300B direct-heated triodes, one per channel, operating in pure class A. It combines Allnic's Inductor Drive circuit, Permalloy-cored magnetics and a silver-contact stepped attenuator in a single aluminium chassis with side handles. The US list price was USD 9,600, with silver and black finishes offered.

Key specs that matter

Rated output is 10 W per channel at 1 kHz, available into 4 or 8 ohm loads, with 0.3 percent distortion at 1 kHz and 2.83 V. Allnic gives a flat response from 20 Hz to 20 kHz, an S/N figure of 80 dB (CCIR, 1 kHz) and a damping factor of 10 into 8 ohm. Voltage gain is 35 dB, 230 mV of input drives the amplifier to full power, and the unbalanced inputs present 10 kohm. On the rear sit four RCA inputs, a single XLR input and a pre-out, with five-way binding posts for the speakers. The case measures 430 x 380 x 240 mm and weighs 22 kg.

Engineering and use context

Four valves make up the signal path. A 6SL7 twin triode with a mu of about 70 forms the first stage, and a 6SN7 with a mu near 20 drives the pair of 300B output tubes. In the Inductor Drive circuit a choke replaces the usual load resistor of the driver, and Allnic states that this yields a voltage swing of around 150 V, against about 70 V from a conventional resistor-capacitor stage. The drive choke uses a 100 percent nickel Permalloy core, and the output transformers are wound on nickel Permalloy as well, with a core large enough not to saturate at 100 mA. About 6 dB of negative feedback is applied, which Allnic uses to raise damping and reduce distortion. The 300Bs run with a self-biased control grid, while a soft-start stage delays the high B+ voltage until the filaments have warmed up. Two analogue current meters, one per output tube, show the state of each 300B. Volume passes through the second version of Allnic's 41-step attenuator, which uses silver contacts and non-inductive resistors instead of a carbon-film potentiometer, and a solid aluminium remote adjusts it from the listening seat. A front selector handles source switching.

Pairing

With a modest power rating, the T-1500 mk2 belongs with high-sensitivity loudspeakers rather than demanding low-efficiency boxes. A DAC or streamer with XLR sockets connects over the balanced input, while the pre-out leaves room to add a powered sub or a bigger power amp in future.

Alternatives

Buyers needing more output can look at the Allnic T-2000 30th integrated amplifier, which has KT170 output valves in push-pull and selectable pentode or triode operation.