Fidelix STACCATO Amplifier for Static Headphones

STACCATO is characterized by its clean bias technology (CBT), which provides extremely pure bias voltage. Of course, it is a complete DC amplifier of all FET, which is a commitment of fidelix, and it is a real-time BTL of class A.

In CBT, the bias current hardly flows, so the ripple voltage hardly comes out. If there is a ripple on the amplifier side, the basic principle is that the true bias voltage calculated by adding the same amount to the bias side becomes clean. This makes it possible to obtain overwhelmingly clear and delicate yet raw sounds.

Condenser headphones are not good at excessive loud volume. The amplifier seems to be powerful, but there is a fear of breaking the headphones. So we introduced a soft clip technique that makes clips less noticeable like photos. Because the clip is inconspicuous, you can increase the maximum volume to 2dB empirically. MOS-FET, which does not generate a carrier accumulation effect, was successfully realized (left side of the photo below). Measurement by probe of 100:1, but almost 400Vrms is out.

The square wave response in the 100kHz at the time of 100pF load is pretty beautiful. (On the right side of the photo)

The power transformer is also independent, and the reverse connection to cancel the leakage flux, and the diode isolator system virtually separates the left and right earths.

XLR input requires four volumes if it is a normal design, but by making it a circuit that can be used in two volumes, the effect of volume on sound quality was reduced by half. The main resistance is the non-magnetic resistance of PRP, the load resistance uses VISHAY's oxide metal film resistance in parallel, and the capacitor adopts PPS. The power supply consists of only a simple ± 300V power supply and uses a SiC that does not cause recovery noise in the rectifier diode. Eliminating connector and relay contacts eliminates contact defects and sound quality deterioration when used for a long time. By using the top plate as a heat dissipator, we challenged the ultimate performance with a small light weight and low cost.

It is an amplifier designed as a product that the designer who was also enrolled in the design and development of Stax wants to continue to use, but the design itself is convinced that it can be used as a reference, the transparency and the outline of the bass instrument as if the distant scenery can be seen clearly and the rhythm is alive. It is a headphone amplifier that demonstrates the true value of condenser headphones suitable for the name of STACCATO.