"The best sound at CES-indeed one of the best sounds I’ve heard at a trade show- undoubtedly came from the big, $191k, three-and-a-halfway (two 1" diamond tweeters, two 7" Omega 7 midrange drivers, and two 11" Nomex-Kevlar woofers in a D’Appolito configuration) Kharma Exquisite Midi Grand Signature floorstanders, driven by Lamm Industries’ ML3 Signature monoblock amps, LL1.1 Signature preamplifier, and LP1 Signature phonostage, sourced by a TechDAS Airforce 1 turntable (with SME 3012-R tonearm and Clearaudio cartridge) and an Aqua La Diva transport and Formula xHD DAC, and wired by TchernovCable. Housed in a large room on the 35th floor, this sensational system was spacious like nothing else at the show-and gorgeous like nothing else at the show, producing a supremely beautiful sound wherein everything was in balance, everything was exquisitely defined (though not over-controlled), everything was imbued with lifelike bloom and color.... it was worth coming to Vegas just to hear this system. "
Jason Victor Serinus | Stereophile: “Formula xHD is an extremely fine-sounding DAC”
The Mono and Stereo Upper Echelon Product Award
"Ladder DACs have revived my interest in digital few years back and it was quite a shift for an analog guy who couldn't stand the digital for more than few minutes."
"The Formula xHD DAC encompass THE very attributes of 21st century high-end audio digital replay with the "set of skills", that were unthinkable few years back. I'm talking about sound quality without even entering the price point."
"Acoustic Quality Formula xHD DAC has now climbed up the ladder and reached the plane, where the sense of realism is more closely mimicking the real thing."
Jason Kennedy | HI-FI +: “The Aqua has the power to get to the parts that others fail to reach.”
Our pure R2R Ladder Optologic DAC, fully-floating (isolated) FPGA-based DAC The Formula DAC is the first in aqua’s history to implement a proprietary resistor ladder conversion system, the Optologic DAC. The signals sent to the resistor ladders are generated by a proprietary digital circuit, programmed inside a FPGA (Field Programmable Gate Array). The Formula has a sign-magnitude converter structure which requires not two but four 24-bit resistor banks; each one made with low tolerance discrete resistors. In order to separate the sensitive analog circuits from the digital section, galvanic and magnetic isolation is implemented between the FPGA, and four branches of the R2R ladder converter. This achieves complete isolation of the entire digital circuit - including clock - from the analogue section resulting in a clean, noiseless, ground plane. It also serves a critical role in the differential management of the R2R ladders, creating perfect symmetry between the counter-phase halves. The result is the highest tonal contrast and naturalness.
Innovation through Technologies The Formula Dac uses no digital filter or any other compensation, relying instead on maniacal attention to each sub circuit. The analog and digital power supplies are executed purely discrete by extensive use of BJT, Mosfet, Jfet and ultra-fast diodes. Passive parts were selected not just for the best sonic result but also for their top quality, longevity and reliability. With the exception of six superior quality electrolytics, all other caps are Tantalum, solid-polymer OS-CON and double-metalized MKP. The signal path itself is direct-coupled and free of all capacitors. The two output stages (one single-ended, one transformer-coupled balanced) use discrete BJT and JFet with metal-film resistors. All the electronics parts show an ultra low RF noise.
The Optologic DAC
"Aqua Acoustic Quality’s Formula xHD is an extremely fine-sounding DAC whose warmth and ability to decode files of extremely high resolution should win it many admirers. Many will also applaud its designer’s rejection of digital filters, oversampling, upsampling, and MQA."