Parasound Halo A21+ 2 2 x 500 Watt 2 Channel Audio Power Amplifier

Changes from the original A 21→A 21+ 250 → 300 Watts (8Ω) 400 → 500 Watts (4Ω) 750 → 1000 Watts (bridged) Filter cap: 88,000 uF → 108,000 uF S/N: 112dB → 115 dB THD (at full power): 0.2% → 0.1% Crosstalk (20kHz): 63dB → 70dB Transformer size: 1.2 kVA → 1.3 kVA Weight: 60 LB → 71 LB Refined Halo cosmetic with aluminum end caps & gold highlights Updated rear panel with heavy duty speaker terminals from JC 5 Upgraded internal gold on gold audio connections Updated auto turn on circuit   All Features 300 watts x 2 @ 8 Ω RMS, both channels driven 500 watts x 2 @ 4 Ω RMS, both channels driven 1000 watts x 1 @ 8 Ω, in bridged mode Circuitry designed by legendary John Curl High bias Class A/AB operation 60 amperes peak current per channel Stable with speaker impedance dips to 1.5 Ω Balanced inputs with discrete circuits CHK Infinium, custom 5-way speaker binding posts Gold-plated RCA input & loop output jacks Direct-coupled signal path, no capacitors or inductors DC Servo and relay