SPL Phonitor One

• The power amplifier

The output stage of the headphone amplifier is designed as a push-pull amplifier in Class AB mode. Bipolar transistors share amplification of the positive and negative half-waves, which produces higher gain and higher output voltage than Class A operation, where a single transistor amplifies both half-waves. The transistors in the output stage are thermally coupled and thus operate particularly coherently, which contributes to a consistent and stable sound image. The power supply has a buffer circuit with low source resistance, ensuring generous current reserves even when using low-impedance headphones.

• The revolution

in the headphone amplifier is the Phonitor Matrix , with adjustable crossfeed, thanks to which you can create mixes with headphones that sound the same on the speakers. The Phonitor Matrix in its largest expansion stage has three setting parameters: crossfeed, Speaker Angle and Center Level. In Phonitor One, the center level is preset to -1 dB and the speaker angle to 30°. These are the most commonly used values.

• NUMBER ONE IN SOUND

For us, sound is always in the foreground. When it sounds good, we like to listen. To achieve such a sound requires experience and technical finesse. We have incorporated both in Series One.

• The design of the amplifier stages
• The preamplifier stage

Two Burr-Brown OPA 2134 SoundPlus operational amplifiers provide the preamplification. These are specially designed for audiophile circuits and feature extremely low noise and minimal distortion of only 0.00008%. With a true FET stage, the OPA 2134 achieves a slew rate of 20 V/µs, making it a high-speed operational amplifier. This has an immediate positive effect on the liveliness of reproduction. In addition, low-capacity film capacitors are installed in the signal path as coupling capacitor bypass capacitors, which ensures more precise transmission of high-frequency signal components. Panasonic's excellent "Electric Double Layer" gold electrolytic capacitors are used as coupling capacitors. They offer the highest storage capacity of all capacitor technologies. The crossfeed function determines channel crosstalk, the so-called interaural level difference. The intensity of crossfeed is fully variable. At the beginning of the control path the function is not in the audio path. It only turns on by summing it through relay ( hysteresis circuit). The audio signal therefore does not pass through the crossfeed stage unless desired.