SmartAmp 20
4 x 125W amplifier with integral DSP
Features
- 4-channel Class D amplification — 125W per channel into 4Ω–16Ω and 70V/100V constant voltage loads
- Rear-panel dip-switch presets — EQ and limiting optimised for a wide range of Optimal Audio loudspeakers
- SmartAmp Custom Configurator for speaker profiles beyond the built-in presets and third-party loudspeaker support
- Power sharing — 250W shared between each pair of channels, distributed flexibly depending on load
- Half-width 1U housing — pairs with a SmartAmp 10 or second SmartAmp 20 for up to 6 or 8 channels in a single rack space
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SmartAmp 20 is a 4-channel Class D power amplifier with onboard DSP, designed to work with Optimal Audio loudspeakers. Rear-panel dip-switch presets cover a wide range of Optimal Audio speakers — an installer selects the preset for the speaker being driven and the system is correctly configured: EQ shaped, limiting set, headroom protected. No external processor required, no manual tuning. For installations requiring custom speaker profiles or third-party loudspeaker support, the Custom Configurator extends this further.
SmartAmp 20 can drive both conventional low-impedance and 70V/100V constant voltage loudspeaker loads. DSP presets are selected by switches on the rear panel, enabling the appropriate EQ and overload protection for each speaker.
The half-width 1U housing enables space-efficient installations. SmartAmp 20 pairs side by side with a SmartAmp 10 or another SmartAmp 20 in a single 1U rack space, providing up to six or eight channels respectively. SmartAmp 20 uses power sharing between each pair of channels — a maximum of 250W is available per pair, distributed according to load. If one channel in a pair requires only 20W, the other can draw the remaining 230W — useful where channels in a pair are driving different speaker types.
Power Factor Correction power supply technology enables universal AC mains operation without the need for local market power regulation. Ultra-low standby power consumption meets EuP2103 and Energy Star compliance.
For standalone installations, SmartAmp 20 pairs with a ZonePad VL1 for simple in-room volume control without a Zone controller. For larger installations requiring multi-zone scheduling and WebApp control, SmartAmp 20 works alongside any Optimal Audio Zone controller.
| TYPE | CLASS D power amplifier with DSP |
| POWER OUTPUT (4Ω -16Ω) | 4 x 125W |
| 70V-100V OUTPUT | 4 x 125W |
| DIGITAL SIGNAL PROCESSING | EQ & limiter presets for Optimal Audio loudspeakers |
| COOLING | Forced air cooling with fan |
| ANALOGUE IN/LINK | 4 balanced line inputs on Euroblock connectors |
| ANALOGUE INPUT IMPEDANCE | 10kΩ unbalanced, 20kΩ balanced |
| MAXIMUM ANALOGUE INPUT LEVEL | +24dBu |
| AMPLIFIER OUTPUTS | Euroblock |
| SIGNAL TO NOISE RATIO | > 100 dB (A-weighted, 20 Hz – 20 kHz, 8 Ω load) |
| FREQUENCY RESPONSE | 20 Hz – 20 kHz (+0/-0.25 dB (8 Ω load, 3 dB below rated power) |
| TOTAL HARMONIC DISTORTION | < 0.05 % (20 Hz – 20 kHz, 8 Ω load, 3 dB below rated power) |
| SLEW RATE | 8.796V/µS at 70 V peak, low impedence, 17.77V/µS at 100 V peak, high impedence |
| DAMPING FACTOR | 370 with 8Ω load |
| CONTROL AND MONITORING | GPIO |
| DSP SAMPLE RATE | 48kHz |
| MAINS POWER INPUT | Universal Mains, 100-240V, 50-60Hz |
| MAINS CONNECTOR | IEC |
| POWER CONSUMPTION | 150W |
| HEAT GENERATED | 540 kJ per hour |
| DIMENSIONS | (W) 220mm x (H) 44mm x (D) 353mm (W) 8.67” x (H) 1.73” x (D) 13.90” |
| WEIGHT | 2.4kg (5.3lbs) |
Optimal Audio SmartAmp 20 Amplifier FAQs
SmartAmp 20 is a 4-channel Class D power amplifier with onboard DSP, designed specifically for use with Optimal Audio loudspeakers. It delivers 125W per channel into 4Ω–16Ω, and supports 70V/100V constant voltage loads. Rear-panel dip-switch presets select the correct EQ and limiting profile for the loudspeaker being driven — no external processor or manual tuning required. The Custom Configurator allows additional speaker profiles to be created for Optimal Audio loudspeakers beyond the built-in presets and for third-party loudspeakers. Power sharing between each pair of channels allows the total 500W to be distributed flexibly depending on the load. SmartAmp 20 works as a standalone system paired with a ZonePad VL1, or alongside a Zone controller for full multi-zone management via WebApp.
The right SmartAmp model depends on the number of channels and output level required. SmartAmp 10 is a 2-channel model suited to single-zone or simple two-zone installations — its half-width 1U housing pairs with a SmartAmp 20 in a single rack space for up to six channels. SmartAmp 20 is a 4-channel model at the same 125W per channel, with power sharing between each pair of channels — the right step up when four channels are needed in a compact footprint. SmartAmp 30 is also 4-channel but delivers 250W per channel without power sharing — the right choice for installations where the higher continuous output per channel is required for more demanding speaker loads. All three support both low-impedance and 70V/100V constant voltage loads. Your installer will advise on the right model based on the number of zones and the power requirement of the specific loudspeaker load.
