Questyle CMA18P Portable

Even before CMA18P's power and signal arrive at the final destination – your flagship earphones and headphones – current-mode amplification is already working its magic.

It eliminates the lag time of the signal that might otherwise occur, as it builds up at the capacitances in the circuit – current signal passes through unhindered as compared to voltage, with speed and ease.

By doing away with the issue of transmission delay in CMA18P, Questyle virtually eliminates any of the harshness caused by the intermodulation distortion associated with high capacitance, solid-state circuits.

That small signal then takes advantage of being unhindered by capacitance in the signal path. An added benefit from current-mode amplification is that huge signal bandwidth is possible, leading to phase response being accurately preserved in the human hearing range.

Indeed, to hear current-mode is to hear a naturalness to music not encountered before in a conventional circuit, and Questyle build CMA18P as a portable TOTL expression of such a topology. 

Now working with Asahi Kasei Microdevices (AKM)’s resurgent AK4493SEQ and a XMOS XU316 USB receiver for a pristine digital decode, the analog section of CMA18P preserves the converted audio to present it smoothly and organically, without exaggerated warmth or bloat.

For those who wish to experiment with other sources, a pair of line-ins are also included. Happily use CMA18P with any low-impedance device bolstered by four desktop-level current-mode amplifiers as Questyle's purest portable voltage source yet. 

CMA18P pushes gear such as Focals, Fostexs, HIFIMANs, Rosson Audio Designs, and CIEM heavyweights Craft Ears, Empire Ears – particularly the Raven, Odin and Legend Evo – and Vision Ears effortlessly.

Driving low impedances is CMA18P's forte. Still, the bridge-tied load balanced operation with four amplifiers outputting means this Questyle also doubles voltage swing compared to single-ended operation, to drive higher impedances like HEDD Audio's HEDDPhone 2 and ZMF Headphones' Caldera credibly too.

CMA18P is all you'll need with the low-impedance gear you'll commonly carry outdoors or at work. Otherwise, explore how Questyle's current-mode scheme in CMA15 can further benefit your planar-magnetic headphones at the desk, or browse our other mobile DAC/amps here.