Aries Cerat R2R DAC - Kassandra Mk2

ok102006

Aries Cerat, a company from Cyprus.

Their design:

• tube signal amplification
• transformer coupling throughout the signal chain
• attention to power supply design
• use extensive choke regulation and polypropylene caps (no electrolytic cap)
• designed, built and tested in-house
• they do customization for your needs
  

...Yet, no DAC converter delivered the sound we expected, as a reference converter. Every dac presented an artificial feel in every recording, and almost all presented compressed dynamics and poor flow of music, easily noticed with un-compressed recordings and ultra high sensitivity horn systems. So, we began designing the best possible digital processor.

Use the AD1865, a 18bit R2R converter, probably the best sounding audio dac presented up to date and especially in the version we use, the AD1865N-K. We went a bit further and used 32 of them, 16 converters per channel.

The 16 converters are working in current mode,and use an I/V transformer so that the current differential is converted in single ended voltage output.No resistors or OPAMPS are used in the I/V conversion stage.

The analog stage is implemented by a single ended transformer coupled triode stage, using a super-tube, the E280F, working in triode mode, loaded with a step down output transformer. The tube power supply is an oversized choke regulated supply.

The converter is equipped with an internal super-clock, which re-clocks the converters, making the processor virtually immune to transport changes. The jitter is attenuated to < 5ps rms , whatever the jitter level is present at the transformer coupled spdif inputs,or the USB asynchronous input. With the internal clock, there is no need for a word clock input. The super-clock re-clocker can be bypassed on the fly, so you can hear the effect of jitter elimination in your system.

Extensive use of 35 LC filters,implemented using RF chokes and high speed capacitors,to decouple all digital circuits, ICs etc from the power rails,as to elliminate PSU sources jitter.

Also available is signature version, with upgrated power supplies. The Signature’s power supply is a complex system of a total of 8 torroidal transformers, for full separation of digital section, analog supplies, clock supply and the tube circuits. A total of > 2.5F of capacitance is present in the system, with more than adequate local de-coupling, high spec foil capacitors, and gas rectifiers for the tube PSU.

• 16 R2R converters per channel, complimentary current output (using the top grade AD1865N-K , 8 converters per bank, 16 per channel)
• Eight discrete ultra-low-noise regulators (for the 4 converter banks)
• Extensive local decoupling, using tuned LC filters
• Overengineered power supplies, power input filters (8 torroidal transformers,over 2.5Farad total system capacitance,wideband local decoupling,Sig version)
• 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)
• 30Vpp output @ 0db
• Balanced output(optional)
• USB input up to 24/384KHz
• Jitter attenuation down to fempto sec level
• Output impendance ~40ohms (balanced output)
• Dimensions : 540mmW X 520mmD X 165mmH
• Weight:   60kg
  

momei

Weight:   60kg !!!
勁 !!

blau.vol

很久很久沒有見廠用AD1865 做DAC project ,  as AD announce obsoleted sometimes ago.

我有印象用AD1865 IC 做project 是好多年前  Rockna Audio Nicolae 做的  DAC kit RD3!    我記得Rockna 出這個AD1865 PCB kit 是 08 年的...... ,  Lampizator 買Rockna 的來做DAC , 話這個kit 好聲tim......

it is ALL old story....  ,  I am TOO OLD!

Lampizator 玩Rockna kit 的 link:

http://www.lampizator.eu/lampizator/REFERENCES/ROCKNA/Rockna.html

Cheers,
Blau
VOLENT