The Legacy Powerbloc4 is the perfect option for bi-amping speakers and high performance surround sound applications. Audiophiles will appreciate the detail and resolution from the ultra-wide 1.5 Hz to 70 kHz bandwidth. Professionals will love the abundance of effort­less power.

Incredible performance in a small package…at a fair price.


Characterized by a solid and taut low end with fully developed shimmer in the top extremes, Powerbloc2 is one of the most versatile refer­ence grade amplifiers ever. Now, the Powerbloc4 provides the same performance across four channels! The Powerbloc4 hosts a pair of 30 amp power supplies, each powering two channels.

The benefits of multi-amplification are inarguable: lower intermodulaton, greater headroom and freedom from harmful clipping. Yet concerns over cost, bulk and complexity have prevented users from enjoying these sub­stantial advantages. The Powerbloc4 can be used to bi-amp passive speakers alongside Legacy Audio’s DSP based processor/crossovers to raise system performance to a new level. They can also be used in high performance theater applications to power center and surround channels.

Numerous refinements to class D topologies in recent years have resulted in improvements that not only match the neutrality of other high end designs, but actually exceed typical performance parameters in several ways:

  • High damping factor
  • Low output impedance
  • Wide bandwidth
  • Huge dynamic range

Stable into low impedances, the Powerbloc4 achieves high output without bridging and is exceptionally quiet. No transformer hum, fan noise or long waits after power cycling for stabilization. Extremely stable even when driven hard, the ultra-efficient Powerbloc amps feature short circuit protection, thermal sensing and 12VDC triggering. Inputs are premium hand soldered XLR balanced and gold-plated RCA inputs, as found only on the finest gear.

The Legacy Powerbloc4 provides configuration flexibility with four channels of serious power… for serious listening.

“I enjoyed a pristine, crystal-clear, and endlessly dynamic movie soundtrack at true high-end commercial-cinema levels.” – Dan Kumin, Sound & Vision Magazine


Less Wasted Power

Power loss of the Powerbloc amplifier and power loss of a Class AB amplifier with highest theoretically possible efficiency.


Power per side: 325 watts per channel x 4 @ 8 ohms, 650 watts per channel x 4 @ 4 ohms

Inputs: 4 balanced XLR, 4 unbalanced RCA

Outputs: 4 pair gold plated safety approved five-way binding posts

Damping Factor: 1,000<1kHz

Voltage Gain: 27.4 dB

Dynamic Range: 117 dB

Peak Current: 30 amps shared channels 1,2 and 30 amps shared channels 3,4

THD: 0.005% at rated output

TIM: 0.0045% at rated output

Input Sensitivity: 2.1 Volts to rated power

Dimensions: 3″ H x 17″ W x 14″ D

Unit Weight: 15 lbs

Shipping Dimensions: 9″ H x 22″ W x 18″ D

Shipping Weight: 22 lbs