Headphone Amplifiers


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Starting At $59.99
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Built for You

We hand assemble each cMoyBB and tweak output power and bass boost for your equipment. Simply specify your headphones during checkout.


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Since its debut in July 2007, thousands of cMoyBBs have been enjoyed by audio enthusiasts in more than 60 countries. The cMoyBB is praised as the best-sounding cMoy not by us, but by our customers, fellow DIY'ers, and reviewers. If you are looking for a fantastic cMoy, or wish to build one, you've found the right amp.


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Features of the cMoyBB v2.03

cMoyBB is the most fully featured cMoy made.

Bass Boost

JDS Labs's success is due to cMoyBB's legendary bass boost switch. Switched off, your original audio signal is amplified. Switched on, bass increases up to 9.4 dB for a perceived 2x increase in bass volume.

Printed Circuit Board (PCB)

Older cMoys use thin wires or protoboard to transfer audio signals. cMoyBB uses a carefully designed PCB with attention to detail that cannot be achieved in protoboard amplifiers, or even in circuit boards designed by experienced hobbyists.

Power System

cMoyBB handles more than twice the voltage of most cMoys and supports dual rail splitters. The result is over 200% higher power handling than the original cMoy! Decoupling capacitors on all power pins significantly enhance opamp stability and sound quality.

Power Input Jack

cMoyBB's power input jack allows you to power the amp from your desk. Optional charging support also provides convenient, integrated 9V NiMH battery charging.


cMoyBB is cased inside of a brand new Altoids Peppermint tin, protecting the circuit from some forms of external EMI / RF interference. You may choose between two tin styles: Peppermint or Wintergreen.


Specify your headphones during checkout and we'll optimize gain, bass boost, and output power for best performance with your headphones. A technical summary ships with each custom cMoyBB.

Tech Specs

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Frequency Response 20Hz-20kHz +/- 0.1 dB
THD+N 20-20kHz, 150 Ω 0.002%
Noise, A-Weighted -90 dBV
Channel Balance +/- 0.6dB
Output Impedance 0.6 ohms
Charge Time - Standard N/A
Charge Time - Rechargeable 10 hours
Run Time 8-50 hours
Output Power 20mW Max

The default cMoyBB produces output power similar to a smartphone. Customized 1x9V cMoyBBs produce higher output current, which is useful for driving low impedance headphones. The 2x9V cMoyBB produces higher output voltage, which is best paired with 150+ ohm headphones. Please see our article Power is Volume for more information.

Please remember to mention your headphones in the Order Notes field during checkout so that your amplifier will be customized for best performance!


Gain 6x (or Custom)
Volume Potentiometer Taper 3B


Case Dimensions 116 x 64 x 21 mm
Weight 3.6 oz


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  • New Bass Boost cMoy v2.03 Headphone Amplifier
  • Free 9V battery (with standard amplifier)
  • Instructions Sheet: Standard, Rechargeable


Standard, 1x9V: Best for most users. External DC jack can be used to power the amplifier. Does not charge battery.
Standard, 2x9V: Recommended for high volume listening with 120+ ohm headphones. Does not charge batteries. Battery run time is identical to the 1x9V edition. Higher voltage enables higher volumes for high impedance headphones
Rechargeable, 1x9: Ideal for portable use of most headphones. Adds integrated charging circuitry and includes 1x9V Tenergy low self-discharge NiMH battery. Requires a 10V+ AC/DC adapter (not included)!

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