Monday, October 24, 2011

APL Reference HA-Master hybrid amplification system












Intro price $35000

The middle Control unit is the "brain" of the amplification system with a master microprocessor inside that monitors and controls everything. The two units you see to the sides are the unique IGBT Balanced Power current converters that are also microprocessor controlled and slaved to the master control unit. The system can be expanded to 4 or 6 power converters total (2 or 3 per channel) when more power is required for bi-amping or tri-amping.

As shown on the picture, with 2 power units, the power rating of the system is 350W per channel at 4 Ohms. Expanding the system with more power units allows for driving more speaker modules with ease. For example, with our Gravitas NB-Master speakers, you can have two power converters per channel - one powering the sub-bass and the other one powering the rest.

The Control unit shown in the middle is remote controlled and has three single ended inputs and one balanced. The inputs are routed to the unique H-Attenuator with precision steps ranging from 0.5dB to 1dB per step. The gain is provided by a Single Ended tube stage featuring 6SN7 driver and 2A3, 45 or 300B output tubes (switchable). The tube stage is transformer coupled to the Balanced power converters using custom Lundahl audio transformers.

Since the Control unit is dual mono configuration with no large power transformers inside, the power for the tubes is provided by the current converter modules for each channel. There are 3 custom made umbilical cords connecting the Control unit and the Power unit (total of 6). One signal, one power and one control per channel.

Please do not confuse the HA-M with a tube preamp (or amp) driving two solid state monoblocks! Every power amplifier has a voltage gain stage in order to amplify the small signal coming from your preamp (or any source) and a power stage so it can drive your speakers. The Control unit of the HA-Master provides all the voltage gain, while the balanced Power converters provide the ample current needed to drive the speakers and have no gain. In other words, the HA-Master system is an unique modular integrated power amplifier.

The HA-Master is an all-hand-made, cost-no-object boutique, that offers unparalleled features and sound quality, combining the sound of Direct Heated Triodes with an amazing power output capable of driving the most difficult loads/speakers. The HA-M has no Negative Feedback and no capacitors on the signal path. It is designed for the most enthusiastic audiophiles who cannot settle for anything else but the best.

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