Pojačalo za slušalice klase A

A slušalica pojačalo has one job: isporučiti napon and struja to a slušalica driver in exact proportion to the input signal. Every deviation from this proportionality is distorzija. The klase A Slušalica Pojačalo minimizes these deviations kroz the most direct means available — a topologija in which the output uređaji are biased to conduct struja kontinuirano, never switching off tokom any part of the signal talasni oblik. In klase B and klase AB pojačala, the output uređaji take turns: one handles the positive half of the talasni oblik, the other handles the negative half, and at the transition point između them — the zero crossing — postoji a brief interval tokom which neither uređaj is fully conducting. This interval proizvodi crossover distorzija, a form of nonlinearity that adds odd harmonics to the signal at every zero crossing. klase A eliminiše this u potpunosti by keeping both uređaji conducting at all times. The penalty is heat. The pojačalo disipira 65 watts kontinuirano, bez obzira na signal level, most of it as termički energy radiated from the kućište. Ovo je the cijena of zero crossover distorzija. We consider it reasonable.

The input stage uses a matched pair of NOS (new old stock) Mullard 12AU7 vakuum tubes — proizveden in Blackburn, England, in the 1960s, prije the factory closed and the tooling was destroyed. We održavati a stock of these tubes sufficient for struja production; when the stock is exhausted, we will evaluate alternatives. The 12AU7 was odabran for its low plate otpor and high linearity, which make it suitable as a napon amplification stage driving the MOSFET output uređaji. The tube's contribution to the pojačalo's harmonic signature is predominantly second-order — a form of distorzija that the human auditory sustav processes as warmth and presence umjesto harshness. Mi ne tvrdnja that tube distorzija is desirable. We tvrdnja that to je less undesirable than the distorzija produced by solid-state input stages operating bez global feedback.

The napajanje is a dual-mono dizajn with separate transformatori for the left and right channels. The transformatori are wound u našem pogonu u Quitu using the same ekvatorijalno namotavanje techniques developed for our kabel products. A shared napajanje creates a coupling path između channels: when one channel draws struja tokom a dynamic peak, the napajanje napon sags momentarily, affecting the other channel's operating uvjeti and producing intermodulation distorzija između the left and right signals. Separate transformatori eliminisati this coupling. Each channel radi as though the other ne exist.

The kućište is machined from a solid billet of 6061 aluminij with a bakar-plated čelik liner on the interior surfaces. The bakar plating pruža elektromagnetsko oklapanje that sprečava radiated interferencija from the transformatori and rectifier from reaching the signalni put. The pojačalo pruža three slušalica outputs — 6.35mm single-ended, 4-pin XLR balanced, and 4.4mm Pentaconn balanced — all driven from the same output stage kroz preciznost resistor networks. Only one output should be used at a time. Connecting slušalice to multiple outputs istovremeno divides the pojačalo's output struja među them in a ratio determined by their respective impedances, which is unlikely to proizvoditi a satisfactory rezultat for any of them.