MBL C21 Stereo Power Amplifier

The MBL C21 is the Cadenza Line stereo power amplifier — 300 watts per channel into 4 ohms with 20 amp peak output current in a single-chassis form. For MBL Cadenza Line systems where two C15 monoblocks would be more amplification than the room requires but the sonic character of MBL’s LASA topology is what the buyer is after, the C21 is the natural amplifier choice.

The engineering underneath is MBL’s original Linear Analogue Switching Amplifier — the ground-breaking Class D topology developed for the Cadenza Line and later refined into LASA 2.0 for the Noble Line. Both generations share the same fundamental character; Noble Line’s LASA 2.0 pushes the noise floor lower and increases peak current delivery. The Cadenza C21 delivers the essential MBL amplifier character at the tier’s entry price.

Speaker load-independent frequency response is the detail that matters most for MBL loudspeakers, because Radialstrahler impedance curves are demanding and many Class D amplifiers audibly shift character across them. The C21 maintains its voicing across the 116 F, 120 MKII, and 126 MKII load without the tonal drift some Class D amps display into difficult loads. Balanced XLR and single-ended RCA inputs; Soft Clipping delivers gentle transition into overload without the aggressive distortion of hard clipping; analogue toroidal transformer with Mu-metal protective shielding.

At $10,600 in current MBL pricing, the C21 is the natural amplifier for a two-piece Cadenza Line stereo separates system built around the C11 preamplifier driving a pair of MBL Radialstrahlers. For the character reference, LMC’s Scottsdale MBL Room runs the flagship 101 X-Treme MKIII on the 6010 D preamplifier and 9008 A monoblocks — the same sonic lineage the Cadenza C21 traces back to. Walk in during business hours or book ahead for a prepared listening session.