SPL Phonitor One d

“With the Phonitor One d, SPL has created an excellent sounding headphone amplifier, plus equally valuable D/A converter, with integrated crossfeed Matrix at an affordable price that meets the highest sound demands.” – Professional Audio

“All in all, a headphone amplifier is a great edition to just about any listener’s set-up, and if you’re looking for one after reading this, the SPL Phonitor One D is absolutely a stellar choice. It features some unbelievable specs for such an affordable unit, and very high quality components to keep the signal as clean as possible to maximise the listening experience.” – Mixdown

“The SPL Phonitor One d is a device that can make the essential difference for audiophile listening in the living room as well as for working in a recording studio.” – Delamar

“With the Phonitor One d, SPL has created an amazing device when it comes to bringing the quality of studio technology to the homes of every music lover at an affordable price. The noble appearance and the high manufacturing quality make the decision for the Phonitor One d easy.” – Miniklangwunder

“I’ve always been happy with my headphones and and my headphone amp attached to the audio interface, but since I’ve heard, tried and tested the combination of a high quality headphone amp with high quality headphones, I have to say there are worlds apart from what I’ve used before and what I was able to test here today.” – Muso Talk

The audiophile headphone amplifier with innovative Phonitor Matrix, 32-bit DA-converter and outstanding sound quality.

The best is just good enough – 32-bit DA-converter

No compromises were made with the converter chip. The Phonitor One d uses the premium AK4490, 32-bit DAC with AKM’s Velvet Sound® – just like SPL’s bigger DACs.

This technology makes the finest details audible thanks to its low-distortion architecture.

It supports sampling frequencies up to 768 kHz PCM (16x CD resolution) and DSD (Direct Stream Digital) playback up to DSD4 or DSD256 (11.2 MHz) resolution.

The Phonitor One d automatically synchronizes to the sampling rate applied to the USB input. No further settings on the device are necessary.

The preamplifier stage

Two Burr-Brown OPA 2134 SoundPlus™ operational amplifiers provide the pre-amplification. These are specially designed for audiophile circuits and are characterized by extremely low noise and minimal distortion of only 0.00008%.
Thanks to a true FET stage, the OPA 2134 achieves a slew rate of 20V/µs, making it a high-speed operational amplifier. This has an immediate positive effect on the liveliness of the playback.

In addition, low capacitance film capacitors are installed in the signal path as bypass capacitors of the coupling capacitors, which ensures a 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 headphone output stage

Weak sound on headphones?
Not enough power?

Not here. Phonitor One d delivers a full headphone sound – and that up to really loud.

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

The output stage transistors are thermally coupled and thus run 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 operating low-impedance headphones.

With the Phonitor Matrix, you can create mixes on headphones that sound just like on speakers.

Music is normally produced and mixed for playback on stereo speakers.

Listening on headphones is different from listening on loudspeakers. The biggest difference is the lack of crossing signals of the sound signal from the left speaker to the right ear and from the right speaker to the left ear.

These crossing signals are missing in conventional headphone listening, because there are no signals crossing from one side of the headphones to the other. This results in an unnaturally wide stereo stage and sound sources are not played back at their correct position in the stereo spectrum.

The SPL Phonitor Matrix can correct this false stereo image with an analog circuitry.