DOGMA 600 MonoBlock Power Amplifier


QUALIA JAPAN will begin sales of its DOGMA 600 MonoBlock Power Amplifier on September 2, 2015. The DOGMA 600 will be marketed at a more attractive price because it uses common parts used in the predecessor model, the INDIGO MonoBlock Power Amplifier.

Although the cost of the DOGMA 600 has been reviewed, it has not been positioned as an entry-level edition.
It has been developed as an analog power amplifier that further promotes the product concepts that are being advanced by QUALIA & COMPANY in its pursuit of next-generation audio equipment.

As part of the future product lineup, we shall be successively releasing the stereo type “DOGMA Stereo Amplifier” and a new line of amplifiers, “GHOST” with remote control support, that build upon technological feedback from development of the DOGMA Series.

The role of a power amplifier is to faithfully use input sound signals to drive speakers – nothing more, nothing less.
With the DOGMA 600, we have created a presence that operates unnoticed, wholly in the background without destroying the individuality of speakers so that audiophiles can enjoy the emotion of music playback. You will be particularly surprised how the presence of the speakers disappears and a three-dimensional sound image will be produced during playback of live sound sources.

Here, we will introduce the circuit configuration that has been further developed from the INDIGO Series.
A feature of this equipment is the powerful playback capabilities based on a complete Non-NFB design that uses eight parallel outputs.

On a power amplifier, the overall feedback that is fed back from output to input is regarded as effective for improving property numerical values. Yet, in terms of sound quality, even though sound may be clear, the sensation of liveliness in sound presence is flat and lost, and reproducibility becomes poor. What we have to be careful of here is that output impedance also increases and speaker drive capabilities also drop when a Non-NFB design is adopted. To solve this problem, we adopted an inverted darlington method at the output stage. This method has the advantage in that output impedance can be freely set by circuit constants. However, that degree of freedom is restricted as long as the device is not ideal. For example, in the high frequency range, the input capacity of the output FET becomes even more restricted.  

For this reason, on adopting this method, output FET drivers larger and more powerful than those used up till now were used. We were also able to remove resistors equivalent to the emitter resistance in bi-polar transistors. As a result of the above processes, we were able to keep output impedance low, and the A class operating range, that was 8 Ω 50 W on the INDIGO MonoBlock Power, also has been extended to 90 W.  

The DOGMA 600 is equipped with an exclusive power transformer for each block. For the main power transformers, two large 650 VA cut core transformers are built in. For the first stage, a 170 VA R core transformer is incorporated, and two small transformers are mounted for the protection circuit and the company indicator in the round window on the front panel. This independently isolated power environment enables natural, three-dimensional playback sound to be achieved.

We hope that DOGMA 600 will be a “tool” that will allow all audiophiles to use this power amplifier for a long time to come and be naturally absorbed in music playback.

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