Fidelix STACCATO electrostatic headphone amplifier

Fidelix STACCATOIn order to bring out the true value of electrostatic headphones, our designers have applied the know-how they have cultivated over many years, and we are proud to say that this is the ultimate headphone amplifier that can be used as a reference.

Unique technology: CBT (Clean Bias Technology)

The biggest feature of STACCATO is that it obtains an extremely pure bias voltage using its unique Clean Bias Technology (CBT). The basic principle of this technology is to cancel the ripple voltage on the amplifier side and bias side and clean the true bias voltage. This makes it possible to reproduce sounds that are overwhelmingly clear, delicate, and yet vivid.

The square wave response at 100kHz with a 100pF load is quite nice. (on the right side of the photo)

Circuit design in pursuit of sound quality

• Complete DC amplifier: This is an all-FET, complete DC amplifier that Fidelix is particular about, and uses Class A real-time BTL.
• SoFootclip technique: In order to protect condenser headphones from excessively loud volumes, we have introduced a soft clip technique that makes the clip less noticeable. This is achieved by the characteristic of MOS-FET that does not cause the carrier accumulation effect, and empirically enables a maximum volume increase of approximately $2\text{dB}$ while reducing the risk of damage to the headphones.

thoroughHigh-FidelitySeparation of parts and power supply

• Complete separation of power supplies: Even the power transformers are configured as independent left and right, and are connected in opposite directions to cancel leakage flux. Due to the diode isolator system, even the left and right earths are virtually completely separated.
• High precision parts: The main resistor is a proven non-magnetic resistor from PRP in the US, and the load resistor is a metal oxide film resistor from VISHAY in parallel. The rectifier diode uses SiC, which does not generate recovery noise.
• Simple signal path: By designing a circuit that allows a 2-gang volume to be used where normally a 4-gang volume is required for the XLR input, the influence of the volume control on sound quality has been halved. Additionally, by eliminating the connectors and relay contacts, it prevents contact failures and sound quality deterioration over long-term use.

Thanks to its ingenious design, such as using the top plate as a heat sink, it achieves a compact, lightweight, and affordable design while challenging the ultimate performance of an electrostatic amplifier.

Transparency and Rhythm That Let You See Distant Scenery

STACCATO is an amplifier planned by a designer who also participated in Stax’s R&D, as a product they wanted to keep using. Its ultimate transparency and speed have been highly praised by experts.

"Transparency that lets you see distant scenery, and lively rhythm."

According to users and experts, the transparency akin to being able to see distant scenery, achieved through CBT technology and the DC amplifier configuration, is especially notable. Sound can be perceived clearly to the depth of the sound stage, and the contours of low-frequency instruments become distinct, allowing rhythm to come alive. It realizes playback with the rapid attack and sharpness truly worthy of the name STACCATO.