xDSD – Premium. Pocket-portable. Perfection.
Part 3 – Headphone amplifier... and then some!
The ‘Cyberdrive’ headphone amplifier stage is one of the pivotal new circuit designs in the xDSD. This new design places all parameters of the
fully analogue system under digital control for a ‘best of both worlds scenario’.
The key components are:
i. A digitally-controlled stepped attenuator IC
ii. iFi proprietary operational amplifiers (W990VST and the high-performance, low-noise, quad J-Fet OV4627A)
iii. Dual-mono power amp IC headphone drivers.
The xDSD draws upon the existing iFi headphone platform but with the circuitry ratcheted up several notches. Performance is increased, both noise and distortion are lowered and the XBass+ and 3D-Matrix+ modules gain electronic switching.
The ‘Cyberdrive’ headphone amplifier provides up to 3.6V output to easily drive high-impedance headphones while offering a low-noise performance that parallels the micro iDSD Black Label’s ‘Eco’ mode with high-sensitivity headphones/IEMs/CIEMs minus the need to switch anything! Simply set volume control as needed and let the ‘Cyberdrive’ circuitry do the rest.
Got Sennheiser HD800s or Focal Utopias? No sweat. The xDSD will drive them to eardrum splitting levels (not recommended!) so, short of the most-demanding HE-6, just connect any pair of headphones.
New volume control system behind the ‘Cyberdrive’
In short, we developed a new ‘the best of both worlds’ solution - a completely digitally controlled process merged with attenuation itself done in the analogue domain. Both power mode switching and volume level are combined in one rotary control, which means the xDSD transparently and evenly adapts power modes as the volume setting is adjusted.
This means that while the volume control operates like a digital control system, every ‘Bit’ of resolution is retained like an analogue volume control. (Digital volume controls built-into DAC chips lose resolution at lower listening levels).
New ‘Cyberdrive’ battery system with extended playback time
We gathered extensive feedback regarding battery-powered products and this aspect of the xDSD has been re-designed from the ground-up.
A dedicated USB micro connector at the rear serves as a charging port. Power is never drawn via its USB type A audio connection. This is reserved for audio only.
In addition, a new 3.8V/2,200mAh LiPo battery (of the same size as its 3.7V equivalent) offers +/- 12% greater capacity, which extends the playback time away from power outlets.
The entire battery circuitry in the xDSD is also subject to the full ‘Cyberdrive’ system, which not only monitors its state and constantly monitors an attached charger, but also manages the way xDSD is used. Depending on the connected load and real usage, to either maximise playback time on battery mode or battery longevity, one of two modes (‘desktop’ or ‘portable’) is automatically selected.
These features were already implemented in the micro iDSD Black Label yet had to be set manually whereas on the xDSD, it is fully automatic and optimised far more extensively by comparison. Finally, in the event of a depleted battery, the xDSD automatically switches over to external USB power and will carry on as if nothing has changed.
On-the-go, depending upon the headphones, the typical listening time is 6-8 hours.
Latest 3D+ and XBass + for Headphones
The 3D-Matrix+ and XBass+ are also under ‘Cyberdrive’ control, hence a simple single multifunction button enables one to cycle through all input options and on/off.
With a pure analogue volume control retaining full-resolution at all volume levels, its selectable 3D+ and XBass+ functions offer both great sensitivity and power performance for the ultimate in headphone enjoyment.
When used in Line Out mode, both are bypassed and a straight 2v signal is sent to the output.
And Finally
With one eye on the future as to how we all enjoy music and one eye on our portable/transportable line-up, it has been a long road to bring the X-series to market.
Though we are satisfied that this new model encapsulates our very best and latest portable audio know-how.