AKSA 100

The Aksa 100 is a solid state, push-pull power amplifier module delivering 109 watts RMS into an 8ohm load and 218 watts into a 4R load, depending somewhat on the regulation of the power transformers. Input sensitivity for 100W output into 8R is 740mV rms into a Zin of 47K.

The bigger brother to the AKSA 55, the AKSA 100 employs the same philosophy and design principles to create a power amplifier with almost the same sonic attributes, but at considerably higher power. The AKSA 100 offers power with glory, and provides a sensible option for people with low efficiency speakers, or a larger listening room.

The AKSA circuit board is extremely compact, and two large heatsinks with 0.37C/watt thermal rating are supplied with the kit. Each pre-drilled heatsink accommodates its own amp module, ensuring that in even the hottest climate this amplifier will always keep its cool. Even the drivers have their own unique, pure copper heatsinks, which also carry the high current supply to both the drivers and the inner pair of output devices.

Designed with sonics, soundstage and high-energy presentation as the primary focus, the AKSA employs extremely refined circuit design and topology to produce a stunning sound quality genuinely rivaling the best audiophile grade amplifiers in the world. The 100W AKSA has won worldwide praise for its vice-like grip at low frequencies on drivers of all types, including ribbons. This remarkable achievement has been realised in a module which, through meticulous industrial and engineering design, is nonetheless easy to construct and set up, and dimensionally very small.

SPECIFICATIONS:

(These results were obtained on 29 December 2002 by Robert L. Jones of California using an HP Model 339 distortion analyser on a stock 100W Nirvana routinely constructed according to the instructions. They are quoted here with his kind permission.)

The AKSA family of audio amplifiers was developed to overcome most of the sonic problems of SS push pull technology, and incorporate some highly innovative thinking, not just dictated by the engineering (which is crucial) but heavily influenced by the subjective issues of listening to music.  Mindful of the engineering issues, the design cycle has also been focused on the audiophile listening experience, and the inspired desire to transfer human emotion via the artform of music.  The justification for this is simple;  people listen to music to be moved, not to marvel at the elegance of the amplifier design or the paper specification. While the latter aspects are important, they are a means to an end, and not the end in itself.

While engineering has been crucial in achieving the goal of the AKSA, the primary focus has remained the transference of emotion, and to a large degree conventional measurements have been downplayed.  In no way does this indicate that distortion measurements, linearity and slew rates are not important, but rather that there is more to this technology than first appears.  The X factor is, in fact, psychoacoustics - the way in which sound is perceived by the human being.

The AKSA amplifiers create a presentation comparable to a quality tube amplifier, whilst delivering stunning resolution and a pure, sweet, musical sound.  This has been achieved at low cost in an attempt to balance the pricing policies of high end audio against the principles of DIY audio.   Like many tube amplifiers, the AKSA 100W amplifier shines with just about any loudspeaker system, including ribbons and horns, regardless of efficiency.

Key features of both AKSA amplifiers are the utter absence of intermodulation, extraordinary low frequency grip, profound emotional communication, startling transients, crystalline clarity, and palpable depth of image.   This last feature is unusual for solid-state amplifiers.

The amplifier is simple to build.  Each channel of the 100W amp is assembled on its own individual 5" x 3" (127mm x 77mm) printed circuit board.  The 100W amp is supplied with one single, ledged 300mm x 75mm heatsink per channel with a thermal capacity of 0.37C/watt, ensuring it keeps its cool at full power in even the hottest climate.

The 100W AKSA is powered from a 49V volt positive and negative supply which is built in dual mono configuration. The best toroids to use for the power supply (they are NOT supplied in the kit) are 33-0-33Vac 300VA types, with 7% regulation or better. These are supplied under part number 077019201 by Plitron, based in Canada. The transformers have little sonic impact, so no specific brand is recommended; most of the power supply benefits accrue from the filter caps and rectifiers. All AKSA amplifiers run very efficiently in Class AB with a quiescent current of 58mA per complementary pair, and deliver imaging, slam and clarity rivalling the best Class A designs but with none of the troublesome thermal problems. AKSAs are part of the green revolution - they are VERY efficient!

This amplifier has won accolades around the globe for its astonishing sonics, especially in North America and South East Asia. While the AKSA uses a time-honored topology tweaked and refined with state of the art components and painstaking dimensioning, it truly represents the pinnacle of development of modern day analogue amplification. The elegance and compactness of this jewel gives it stunning looks as well as performance, and the low cost guarantees it will be a top seller for decades to come.

Like its smaller brother, the 100W AKSA is also available with Nirvana and a Nirvana Plus upgrades, which take a spectacular presentation to the ultimate, stratospheric heights. The Nirvana Plus upgrade is a no-holds barred, no-compromise approach to component choice and dimensioning and the result of many months of rigorous R&D.

The designer, Hugh R. Dean, an Australian with an eclectic background in education, computing and language training, stands behind his product with unsurpassed email backup.

Build this amplifier, and join the growing cadre of blissful AKSA owners, many of whom go on to buy more amplifiers for multi-amp Home Theatre installations.

If you have any questions about the AKSA and are considering purchase, ask one of the owners! You can find them in the Aspen Amplifiers section at: www.audiocircle.com

BUILDING THE AKSA:

WHAT'S INCLUDED?

The kitset comprises:

A pair of high grade PCBs, specification matched power output devices, all passive and active components, a custom power supply pcb with ultrafast rectifier diodes and the full complement of filter capacitors, a premium quality, pre-drilled and tapped heatsink, extensive and detaied instructions, and full support and backup. Even a self-adhesive AKSA badge is included!

More ASSEMBLY DETAILS can be found here

WHAT YOU HAVE TO SUPPLY:

There are a number of essential components that you need to supply. (Mostly these are the large, heavy components that are impractical to ship around the world one at a time!)
Because the AKSA kitset has been conceived as affordable high end audio for everyone, the option choices you make depend on your preferences and budget. We offer only one option when you purchase - the Nirvana upgrade option. (See below)

YOU WILL NEED:

A case to mount the components in, connecters and wire, a mains switch and IEC power entry module, the power supply transformers (two required of 33-0-33Vac secondary voltage and 300VA rating), an indicator LED, rubber feet for the case, and several small fasteners.

Tools and facilities:

A Workbench of some sort, A fine Soldering Iron, Long Nosed Pliers, fine Side Cutters, Multimeter, Reading Lamp, Philips Screwdriver, Moist Sponge, Sharp Razor, Jeweller's screwdriver, Superglue sachet, School compass.

SOURCES for other components can be found at CONTACT/SUPPLIERS

UPGRADE OPTIONS:

Nirvana and Nirvana Plus upgrade kits:

Two upgrades are available. The Nirvana uses very high quality components selected after exhaustive listening tests. The Nirvana Plus adds even more components in the audio jewelry category to further enhance performance. In accordance with our philosophy of affordable, DIY audio, these grades of components are not included in the regular kit because of their higher cost and significant sourcing difficulties.
By upgrading these sonically critical components in two distinct stages, the AKSA amplifiers become not merely outstanding, but, by degrees, exception, and ultimately sublime.

PRICES:

The prices for all our products can be found at: BUYING/PRICELIST