SPL Phonitor One d

Two Burr-Brown OPA 2134 SoundPlus™ operational amplifiers take care of the pre-amplification. These have been specially developed for audiophile circuits and are characterised by extremely low noise and minimal distortion of just 0.00008%.

Thanks to a genuine FET stage, the OPA2134 achieves a slew rate of 20V/µs, making it a high-speed operational amplifier. This has an immediate positive effect on the liveliness and joy of playing.

Furthermore, low-capacitance film capacitors are installed in the signal path as bypass capacitors for the coupling capacitors, which ensures more precise transmission of the high-frequency signal components.

The excellent Panasonic 'Electric Double Layer' gold electrolytic capacitors are used as coupling capacitors. They offer the highest storage capacity of all capacitor technologies.

The output stage of the headphone amplifier is designed as a push-pull amplifier in Class AB operation. The bipolar transistors share the amplification of the positive and negative half-wave, which produces a higher amplification and a higher output voltage than in Class A operation, in which only one transistor amplifies both half-waves.

The output stage transistors are thermally coupled and therefore run particularly coherently, which contributes to a consistent and stable sound image.

The power supply has a buffer circuit with low source resistance and thus ensures generous current reserves even when operating low-impedance headphones.

The Phonitor Matrix has three setting parameters in the largest configuration: Crossfeed, Speaker Angle and Centre Level.

In Phonitor One d, the centre level is preset to -1 dB and the speaker angle to 30°. These are the most commonly used values.

The crossfeed function determines the crosstalk between the channels, the so-called interaural level difference. The intensity of the crossfeed is infinitely variable.

At the beginning of the control path, the function is not in the audio path. It is only switched on by adding it via a relay (hysteresis circuit). The audio signal therefore does not pass through the crossfeed stage if this is not desired.