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Compact black stereo amplifier with front bass and treble knobs and a power button

Fosi Audio

Fosi Audio BT20A 100W x 2 Bluetooth Home Audio Speaker

SKU CH-QZ3F-XTJQV MPN BT20A

Compact Class D stereo amplifier delivers 100 W per channel to passive speakers with Bluetooth and RCA inputs, plus bass and treble controls

  • 100 W per channel drives passive speakers to high volume
  • Bluetooth streaming from phones and tablets with no dropouts
  • Bass and treble knobs let you tune the sound to taste
  • Class D design delivers 98 dB SNR and 0.04 % THD
  • Compact all-black chassis fits on any shelf or patio

Compact stereo amplifier for passive speakers

The Fosi Audio BT20A is a two-channel Class D amplifier built to drive passive bookshelf, ceiling or outdoor speakers from a small desktop or shelf footprint. It delivers up to 100W per channel into loads from 2 to 8 ohms, making it suited to listeners who want a simple, affordable way to add wireless streaming to existing speaker pairs without a full-size receiver.

Class D efficiency with low distortion

The integrated 24V 4.5A power supply feeds a circuit rated at 0.04% THD and 98dB signal-to-noise ratio, so music stays clean at typical living-room volumes. Class D topology keeps heat modest and the all-black aluminium chassis acts as a silent heatsink, eliminating fan noise entirely for bedroom or office use.

Upgrade path from basic integrated amps

This unit replaces older mini-amplifiers that lack Bluetooth or tone controls, adding wireless streaming from phones or tablets plus bass and treble knobs for quick tuning. It is not for buyers who need multi-room zones, digital optical inputs, phono pre-amplification or power beyond 200W total for larger venues.

How it compares

Measured against everything we stock in Home Speakers & Subwoofers, at today’s prices. Recalculated every night.

Price $67.99
Cheaper than about 76% of the 1,147 comparable items (median $133.99).

Specifications

Size & build
Shipping weight0.91 kg
Package size267 × 185 × 69 mm

Questions about this item

How do I connect passive speakers to the BT20A and what impedance range must they match?

Connect speaker wire to the binding posts on the rear panel. The amplifier accepts a terminating impedance of 2 Ohm to 8 Ohm, so verify your speakers fall within that range before powering on.

What ongoing maintenance does the BT20A require and which part is most likely to need replacement?

The unit has no user-serviceable parts inside. The external 24V 4.5A power adapter is the only component that typically wears out over time; keep vents clear of dust and replace the adapter if the amp fails to power up.

At what point does distortion become audible during extended high-volume playback?

Total harmonic distortion is rated at 0.04% at the 100W per channel maximum output. Sustained operation at or near that level will hit the distortion limit before thermal protection engages.

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