The Butte


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–noun Western U.S. and Canada

an isolated hill or mountain rising abruptly above the surrounding land.


The Apex Butte is an affordable class-AB headphone amplifier built with the same quality design as the other Apex products.  Small in size, it can still deliver a lot of power to drive virtually any headphones.

The Butte is a DC-coupled design, so it can deliver bass punch that no cap-coupled amp can deliver.  It has incredibly low distortion and an insanely wide frequency response.  It is very transparent.



Click on the photos for a full resolution version



Coming Soon



Measurements and Specifcations

NOTE:  Please read the page about headphone & amp specs!

Values are typical.  

Max output leven into 150 ohms @ 1kHz: 7.2V RMS / 20V P-P / 340mW

Max output level into  33 ohms @ 1kHz: 5.0V RMS / 14V P-P / 750mW

Peak output current: 200mA

Input impedance: 50k ohms

Output impedance: 3 ohms

THD+N 1V 1kHz 150 ohms: 0.003%

THD+N 1V 1kHz 33 ohms: 0.005%

FR: 20-20kHz +/- 0.1dB

FR: -3dB DC – 240kHz

Noise 400Hz – 30kHz: 30uV

Max gain 1kHz: 20dB

DC offset: +/- 5 mV


Power:  120  VAC, 60Hz, 15 watts max. (consult Apex for other voltages)

Dimensions:  4.3" W x 5.3" D x 2" tall 



FFT: 1V RMS @ 1kHz into 33 ohms:



*the peak at ~28kHz is a measurement artifact



FFT: 1V RMS @ 1kHz into 150 ohms:


*the peak at ~28kHz is a measurement artifact



Frequency response:






THD+N vs. frequency





THD+N vs. output voltage (1kHz into 33 ohms):




THD+N vs. output voltage (1kHz into 150 ohms):