By Lam Seng Fatt
It was an eye-opening (or was it ‘ear-opening’?) experience at the launch of the Aries Cerat Kassandra 2 Limited Edition DAC at Swedish Statement Boutique in Jaya One by its designer Stavros Danos yesterday.
If you thought you need the latest-generation DAC chips for the best sound, then head to Swedish Statement and listen to the Kassandra 2 which uses the AD1865N-K DAC chip, an 18-bit model which is considered obsolete.
The AD1865 is a Non-Oversampling chip which many have compared favourably with the legendary Philips TDA 1541 chip.
From the AD1865 spec sheet: “The AD1865 is a complete, dual 18-bit DAC offering excellent THD+N and SNR while requiring no external components. Two complete signal channels are included. This results in cophased voltage or current output signals and eliminates the need for output demultiplexing circuitry. The monolithic AD1865 chip includes CMOS logic elements, bipolar and MOS linear elements and laser-trimmed thin-film resistor elements, all fabricated on Analog Devices’ ABCMOS process.
“The DACs on the AD1865 chip employ a partially segmented architecture. The first four MSBs of each DAC are segmented into 15 elements. The 14 LSBs are produced using standard R-2R techniques. Segment and R-2R resistors are laser trimmed to provide extremely low total harmonic distortion. This architecture minimizes errors at major code transitions resulting in low output glitch and eliminating the need for an external deglitcher. When used in the current output mode, the AD1865 provides
two ±1 mA output signals.
“Each channel is equipped with a high performance output amplifier. These amplifiers achieve fast settling and high slew rate, producing ±3 V signals at load currents up to 8 mA. Each output amplifier is short-circuit protected and can withstand indefinite short circuits to ground.
“The AD1865 was designed to balance two sets of opposing requirements, channel separation and DAC matching. High channel separation is the result of careful layout. At the same time, both channels of the AD1865 have been designed to ensure matched gain and linearity as well as tracking over time and temperature. This assures optimum performance when used in stereo and multi-DAC per channel applications.”
The designer of the Kassandra 2 DAC, Stavros used 24 (Yes, 24!) of the AD1865N-K converters per channel in a balanced design. So there are 48 of those chips in total in his DAC.
Let’s look at the specs:
* 24 R2R converters per channel, complementary current output
(using the top grade AD1865N-K , 12 converters per bank, 24 per channel,48 in total)
* Eight discrete ultra-low-noise regulators
(for the 4 converter banks)
*Extensive local decoupling,using tuned LC filters, 76 in number
*Overengineered power supplies,power input filters
*5 torroidal transformers,over 3 Farad total system capacitance,wideband local decoupling
*Pseudo-battery system, for isolating all analog stages from the power grid.
* Transformer I/V conversion
(custom wideband transformers,balanced current to SE voltage conversion)
* Internal Super-Clock
(bypassable on the fly. Separate torroidal transformer,triple regulated supply)
*Transformer loaded super tube output stage
(using the E280F tube. 5:1 step down transformer, double choke filtered supply)
*xenon gas rectifiers for the tube PSUs
*Super-capacitors used in tube analog stage. 100 times less ESR/ESL than any film or electrolytic capacitor.
The Kassandra 2 Limited Edition DAC comes in two boxes – one is the power supply. Both boxes are huge and heavy and look not only well made but over engineered.
In Swedish Statement’s showroom, the Kassandra 2 DAC was fed CD rips (16/44.1) by a laptop and was connected to a super high-end system comprising Vitus pre and power amps and a pair of Marten Coltrane 3 speakers.
Stavros played a selection of songs ranging from jazz to classical to rock.
How did it sound? From the first ‘thwack’ of the drum stick on a snare drum, I realised that this DAC sounded like a top-flight turntable. Many DACs lose out to vinyl in terms of the attack of musical notes, the first split second of dynamic sound like the ‘thuump’ of the drum stick hitting a tom tom, the ‘twaang’ of metallic sizzle when the drum stick hits the cymbals and the ‘thuum’ of the finger pulling the strings of a bass guitar. But the Kassandra reproduced all that attack … and the sustain, and the bloom of the music.
The music it produced was very transparent with layers and layers of instruments and tons of micro details. The soundstage was wide and deep and palpable with very dense images.
I told Stavros later that his DAC sounded very much like a very good turntable and he nodded his head, smiled and said it was designed to narrow the gap between analogue and digital.
Stavros is from the camp that prefers PCM and his DAC processes files in PCM. He prefers R2R DACs because he opines that it is the best way to convert digital files.
He says there is nothing wrong with the ADC (Analogue to Digital Conversion) part of digital music. “It’s there, you can hear it. The ADC captured all the music, but the DAC part had the issues,” he said.
“What was the main thing wrong with the DAC part?” “It was the delta-sigma chips,” he said. The industry switched to delta-sigma chips because they were cheaper to make, but it created problems and they then tried to solve those problems.
Stavros opines that there is nothing wrong with the Red Book specs and 16-bit 44.1kHz can capture everything in music even though the Kassandra 2 DAC can handle PCM files up to 384kHz.
After listening to the 16/44.1 files that he played, I have to agree with him that he has a point and indeed his Kassandra 2 DAC does peel away a lot of hash to reveal what digital is truly capable of achieving. I have to state that the Kassandra 2 Limited Edition DAC was one of the best DACs that I have heard.
As for the price, well, it is for the super rich. For more details, call Swedish Statement.