Интегральные усилители — Cary Audio CAD-300SEI

The CAD-300SEI is a vacuum tube integrated amplifier from the American company Cary Audio. The circuit is single-ended and operates in pure Class A, using a pair of 300B triodes in the output stage, and it combines the preamplifier and power sections in one chassis with a headphone jack on board. Cary builds it with zero feedback, and remote volume control is standard. The retail price is USD 6,995.

Key specs that matter

Cary rates output at 15 W per channel. Frequency response is 20 Hz to 23 kHz within plus or minus 0.75 dB, noise and hum sit 90 dB below full output, and input sensitivity is 0.42 V for full output. The chassis is 203 mm high, 356 mm wide and 356 mm deep and weighs 23 kg. The amplifier runs from 117 or 234 V AC at 50 or 60 Hz and draws 107 W in operation.

Engineering and use context

Five tubes make up the signal path - one 6SN7 at the input, two 6SN7 as drivers and two 300B output triodes, one per channel. Because each channel uses a single output tube, the circuit is single-ended rather than push-pull, and the output transformers must carry a steady DC current. For this reason Cary uses two EI laminate output transformers with an air gap, both rated for a 200% duty cycle, along with one EI laminate power transformer of the same rating. The power supply uses two 1200 uF capacitors rated at 250 VDC. Signal parts are 1% metal film resistors and polypropylene film capacitors with hand-soldered copper terminals. Three line inputs are labelled CD, AUX1 and AUX2. The maker gives a warm-up time of 3 minutes and quotes 100 hours of break-in. Cary finishes the chassis in anthracite black and fits a faceplate of silver or black aluminium, and a metallic Jaguar blue chassis with a high gloss clear coat and a black anodised faceplate is also offered. Cary offers factory upgrades, among them a Greyhill switch, Hexfred rectifiers, WBT speaker binding posts and MCap Supreme EVO SilverGold capacitors.

Pairing

With its modest output, the CAD-300SEI suits loudspeakers of high efficiency that do not need large amounts of power to reach normal levels. A CD player, streamer or DAC with a line level output plugs into any of the three inputs, while vinyl playback requires a separate phono stage, since none is built in. The phono gap aside, the headphone jack lets the amplifier drive headphones rated between 4 and 50 ohm.

Alternatives

The Cary Audio SLI-80HS is another valve integrated amplifier in the Cary range that also offers a headphone section.