Today, let’s take a look at the intriguing features of the Astell&Kern PA10, a portable Class A amplifier designed by AK to provide excellent driving power for audio players with low output. This amplifier offers the opportunity to pair it with headphones that are difficult to drive.

The PA10 features the Teraton Alpha sound processing and power management chip, which is also used in AK’s audio players.

What is the PA10?

The PA10 is a headphone amplifier that does not have a built-in DAC. It is designed to be used with DAPs or smartphones that have low driving power. The signal is sent from the source to the PA10 to provide sufficient driving power for power-hungry headphones. The PA10 is designed as a Class A amplifier, delivering clean and high-powered sound with low distortion for clear and natural audio reproduction.

Exterior Design

The AK design concept for the PA10 is called “SLOPE,” which gives it a beautiful and luxurious appearance. The chassis is made of aluminum and silicone to support the DAP or smartphone and prevent scratches or color transfer from the devices.

Teraton ALPHA

AK has equipped the PA10 with the Teraton ALPHA chip, the same chip used in their audio players. It helps enhance power management, reduce noise, and unwanted interference, resulting in a Class A amplifier that is energy-efficient, highly efficient, and produces a quiet background according to AK’s sound tuning philosophy.

True Balanced Circuit Design

Typically, portable amplifiers convert unbalanced signals to balanced signals, which may result in some quality loss during the conversion process. AK chose to separate the signal channels to ensure complete and unaltered sound quality. Therefore, if you want to use the balanced input, you need to use headphones with a balanced connection to achieve the desired sound quality.

Additional Options

On the side of the device, you can adjust three main settings:

  1. Gain adjustment with two levels: Low Gain (Unbalanced 2.1Vrms / Balanced 4.2Vrms) and High Gain (Unbalanced 3.1Vrms / Balanced 6.2Vrms).
  2. Current adjustment with three levels: Low (default), Mid (+50mA), and High (+100mA).
  3. Crossfeed mode helps reduce listener fatigue during extended listening sessions and provides a soundstage that resembles listening through speakers. This differs from regular headphones, which separate the left and right channels and can cause ear fatigue during prolonged use.

Sound Review

The PA10 acts as an amplifier to enhance the continuity and smoothness of the sound, providing a seamless listening experience. The tonal balance is warm, delivering both soft and detailed textures. The bass is moderate, impactful, tight, and well-controlled without any bloated or muffled qualities.

The midrange is thick, lush, and clean, allowing different musical instruments to be heard clearly. The imaging of vocals is excellent, revealing more details in the singing. The high frequencies are crisp, lively, and well-extended, without sibilance or harshness, even at higher volumes.

The PA10 excels in creating a well-defined soundstage, with instruments well-positioned according to the size of the stage. This adds a sense of realism to the music.

Interesting Specifications

  • Analog Input: Unbalanced 3.5mm / Balanced 4.4mm
  • Headphone Output: Unbalanced 3.5mm / Balanced 4.4mm
  • Weight: Approximately 325g
  • USB-C charging (can listen while charging)
  • Maximum continuous usage time: 12 hours
  • LED indicator for battery status (White: 70% or more, Yellow: 69%-30%, Red: 30% or less)
  • LED indicator for charging status (Blue lights flashing: charging, Blue lights solid: charging completed)