Усилители мощности стерео — TEAC AP-505

The AP-505 is an ultra-compact stereo power amplifier from TEAC built around a Hypex Ncore module, designed so that two units can be combined for bi-amping or bridged mono operation. Its A4-sized body measures 290 x 84.5 x 271 mm and weighs 4.4 kg, and the external panels at the front, top and sides are high-grade aluminium alloy fixed to a steel inner chassis.

Key specs that matter

In stereo and bi-amp modes maximum output is 90 W per channel into 8 ohm and 130 W per channel into 4 ohm (1 kHz, JEITA), with rated figures of 70 W and 115 W at 0.8% THD. In BTL bridge mode a single unit gives 250 W into 8 ohm maximum and 220 W rated. Distortion is 0.0015% at 12.5 W into 8 ohm, S/N stands at 113 dB (IHF-A) and frequency response runs from 10 Hz to 50 kHz (+0/-5 dB). The damping factor is 370 or higher, with 22 mOhm output impedance. Input sensitivity is 1.3 V on the XLR pair and 0.66 V on the RCA pair, both at 10 kohm or higher. Power consumption is 106 W, with 0.1 W or less in standby.

Engineering and use context

Balanced signal handling extends from the input section to the output stage, which removes common-mode noise. MUSES8820E dual op-amps are used at the input for both XLR and RCA, and the XLR section omits coupling capacitors. The input stage supply has fully independent left and right rectifying circuits from the transformer onwards, with four 4700 uF capacitors per channel. The main supply uses a high-capacity toroidal transformer with Schottky barrier diodes. The unit rests on TEAC's patent-pending Pin-Point feet, which combine a spiked top section and a basin-shaped base and support the chassis at three points with a very small contact area, and they are covered by Japan patent numbers 4075477 and 3778108. Cooling is passive with no fan. Analog level meters on the front have a four-step dimmer (bright, mid, dim, off) and switchable sensitivity of 0 dB, +20 dB or off. Gold-plated screw terminals accept AWG8 cable and banana plugs. TEAC contrasts the A4 footprint with conventional bi-amp and BTL capable power amplifiers, which are usually full-width units, and the European version runs on AC 220 to 240 V.

Pairing

Stereo and bi-amp modes accept speakers from 4 to 16 ohm, while BTL mode needs 8 to 16 ohm. With two units, bi-amp mode drives woofer and tweeter separately, and BTL mode turns the pair into two mono amplifiers.

Alternatives

TEAC's AP-701 is the larger stereo power amplifier, with a dual-mono layout, two toroidal transformers and two Hypex Ncore modules.