The Ithaka d/a converter spawned out at the same time we developed our new generation of our TriodeFet technology featured in the Quintessence Power amplifiers, and was not a coincidence. Our top line-level technology, the Inverted Triode is already used in our flagship converter , the Homerus. However, mating one of our top digital banks , to our current top med-high power technology, the TriodeFet, was an idea that was on paper but not on our immediate plans. However, some experimental prototypes demonstrated and easily convinced us that this new technology has to become available..now.

Fast forward, the Ithaka is proudly out. 

The Ithaka is a ladder DAC. Typically a ladder DAC uses a resistor network switched by a N number of switches, N being the bit depth. It is a passive sort of speak procedure with no manipulation of the incoming data stream.

It also has no digital filter, and completely avoids the negative sonic aspects created by fitting the common Delta-Sigma or Multibit architecture.

In the case of the Ithaka we choose to use an R2R IC – the classic Analogue Devices AD1865N-K, a much praised chip which we believe is the best sounding IC ever made. No less than 24 R2R converters per channel. The AD1865N-K has a very straight forward data handling logic, and does not process the data stream in any way. This gave us the freedom to fully exploit the IC in our converter system.

The input data is latched and directly refreshes the resistor network, with absolutely no additional complex logic or data handling/processing. This way we have full control over the resistor network to use it as part of our converter system. Our Super Clock circuit directly re-clocks and drives the “refresh” signal, so absolutely no additional jitter is induced in the conversion.

There are no less than 24 R2R converters per channel in the Ithaka working as parallel switched resistor ladder converters, cancelling the deviation of resistor values down to Zero. Paralleling R2R converters improves linearity and noise figures are improved on the same principles, along with the dynamic range and channel separation. Sonic wise, paralleling converters elevate performance to another level in all aspects significant in high end audio.

The crown jewel of the Ithaka concept , is the output stage. This is based on our latest generation of our  TriodeFet technology (the specific TF generation  is only used in our top SE amplifier, the QuintEssence).

The output stage is Single Stage-Single Ended circuit, and it’s ultra wide-bandwidth , extreme linearity allows the digital bank qualities to shine through.

With an output impedance of 1 ohm, the output stage is as potent of a speaker amplifier, as it can deliver 12W if the converter it directly connected to any speaker. It is however not the D/A purpose to be used as power amplifier, however is a sample to it’s output stage potency.

(During developing, the d/a was used to drive speakers directly allowing us to perfectly tune and evolve the sound of the Ithaka.)

Technical Specifications

DIGITAL SECTION

IC Chip Array: 24 R2R converters per channel, complimentary current output using the top grade Analogue Devices AD1865N-K  with 12 converters per bank, 24 per channel, 48 in total

Current to Voltage Conversion: Transformer I/V conversion with custom wideband transformers, balanced current to single ended voltage conversion.

Additional Clock: Internal Super-Clock by-passable on the fly, triple regulated supply, quad-stage pre-filters

Regulators: Eight discrete ultra-low-noise regulators for the 4 converter banks,quad-stage pre-filters

POWER SUPPLY SECTION

PSU: Massively over engineered power supplies, power input filters

PSU filtering: Extensive local decoupling using tuned LC filters

Mains Transformers: 2 Low noise 500VA torroidal transformers, over 4 Farad total system capacitance, wideband local decoupling

Pseudo-battery system: Four independent Pseudo-battery systems for isolating all analog and digital stages from the power grid, Quad-stage pre-filters

TriodeFet PSU: Triple choke-filtered, veru high current capacitor supplies

INPUT & OUTPUT SECTION

Gain Stage: Third Gen TriodeFet output stage, Single-Stage, Single Ended circuit. 1A idle current Class A operation.

Output Range: RCA: 30Vpp output @ 0db 10Vrms

Balanced output: standard

User Selectable Output Tuning: User can pre-load the output stage using external resistive modules, to fine-tune the sound.

Output: 2 x RCA, 2 x Balanced. True Balanced output standard.

Floating RCA output switchable (ground loop resolver).

Output Impedance: 1 ohm (balanced and SE output).

Minimum resistive loading to outputs:3ohm.

USB input: Data rates up to 24/384KHz

Other inputs: AES/EBU, S/PDIF, BNC.

Jitter attenuation: Down to femtosec level

Dimensions: 540mm W x 580mm D x 165mm H

Weight: 160kg total unpacked