Rainbow
Rainbow Audio SL-M2 2 channel micro amplifier
SKU: SL-M2
Rainbow Audio SL-M2 2 channel micro amplifier
Closeout, remaining stock
Rainbow Audio SL-M2 2-Channel Micro Amplifier
Class D two-channel in an 86 x 64 x 43mm chassis. 2 x 90W at 4 Ohm, 2 x 120W at 2 Ohm, 240W bridged at 4 Ohm. 5Hz to 25kHz, THD under 0.2 percent.
- Closeout
- Discontinued
- Bridgeable
- Final sale
What You Are Buying
A two-channel Class D amplifier small enough to go behind a dash panel, under a seat, or inside a motorcycle fairing. The chassis is 86 by 64 by 43 millimetres, which is roughly the footprint of a credit card folded in half.
Rainbow part number 280002. Discontinued line, remaining stock only, and we are not restocking it.
Read this before you buy
Final sale. No returns, no exchanges, no manufacturer warranty. Discontinued model with no replacement pipeline.
Reading the Power Ratings
Three figures, and they are internally consistent, which is worth checking on any amplifier claim.
- 2 x 90W RMS at 4 Ohm. The number that matters for a normal door speaker install.
- 2 x 120W RMS at 2 Ohm. A 33 percent increase from halving the load, which is what a real supply does. An amplifier that claimed to double here would be claiming a power supply the chassis has no room for.
- 1 x 240W RMS bridged at 4 Ohm. Bridging doubles the voltage swing, so a 4 Ohm bridged load looks like 2 Ohm to each channel. 2 x 120 = 240. The arithmetic closes.
Do not bridge into less than 4 Ohms. A 2 Ohm bridged load presents each channel with 1 Ohm, and nothing about this chassis says it will survive that.
The Rest of the Sheet
5Hz to 25,000Hz
Full bandwidth. This is a straight amplifier, not a subwoofer amplifier with a fixed low-pass baked in. It will pass whatever you send it.
Input sensitivity 0.4V to 13V
An unusually wide range and the most practical specification on the sheet. The low end accepts a weak preamp output. The high end accepts a speaker-level signal from a factory head unit without a separate line output converter, which on an OEM integration job saves you a box and a set of connections.
Signal to noise over 90dB, THD under 0.2 percent
Both quoted as bounds rather than typical figures, which is the honest way to publish them. 0.2 percent THD is fine for a Class D amplifier of this size and is not going to be what you hear in a car.
Where a micro amplifier is the right answer
Motorcycles, UTVs, boats, and any car where there is nowhere to put a normal amplifier. Also good for adding real power to a pair of pillar or dash speakers in a system that already has a subwoofer amplifier. It is not the right answer if you have the space for a full-size chassis, because you are paying for the packaging.
Who This Suits
Buy this if
- You have nowhere to mount a full-size amplifier.
- You are running speaker-level output from a factory head unit and want to skip the converter.
- You need 90W per channel and no more.
- You accept a final sale on a discontinued product with no warranty path.
Look elsewhere if
- You need more than 120W per channel.
- You want built-in crossovers or DSP. This is a straight amplifier.
- You want to bridge into 2 Ohms.
- You want warranty coverage or the option to return.
Installation
- Fuse the power wire within 18 inches of the battery. On a small amplifier hidden inside a panel this is not optional; you cannot see it fail.
- Mount it where air can move around it. Class D runs cool, not cold, and a 43mm chassis buried in foam has nowhere to put its heat.
- Set the gain by ear: turn it up until the output is clean at your normal maximum volume, then back off. Gain is an input matching control, not a volume knob.
- Bridged mode requires a 4 Ohm minimum load. Check the impedance of whatever you are wiring before you connect it.
- Keep the RCA or speaker-level input runs away from power wiring. A small chassis with a 0.4V sensitivity setting is more sensitive to routing than a big amplifier is.
Condition and sale terms
Closeout stock from a discontinued Rainbow line. Sold as a final sale with no returns, no exchanges and no manufacturer warranty. Packaging may show shelf wear from storage. Specifications are as published by Rainbow. Once remaining stock is gone this listing will be removed.
Questions on wiring, impedance or integration: contact us.
| Type | 2-channel Class D amplifier |
|---|---|
| Part number | 280002 |
| Condition | Closeout, discontinued |
| RMS power at 4 Ohm | 2 x 90W |
|---|---|
| RMS power at 2 Ohm | 2 x 120W |
| RMS power bridged at 4 Ohm | 1 x 240W |
| Minimum bridged load | 4 Ohm |
| Frequency response | 5Hz to 25,000Hz |
|---|---|
| Signal to noise ratio | Greater than 90 dB |
| Total harmonic distortion | Less than 0.2 percent |
| Input sensitivity | 0.4V to 13V |
| Dimensions, L x W x H | 86 x 64 x 43mm |
|---|
Bridged operation requires a 4 Ohm minimum load. Bridging presents each channel with half the load, so 4 Ohm bridged looks like 2 Ohm per channel. That is why the bridged rating equals the 2 Ohm stereo rating doubled.
