Didn't need a lot of power as I'm using with TV 5.1 sound system, as far as that goes works great. The amp detects when signal is coming in and LED goes from RED to GREEN and passive bass comes alive. I realized from photo and manufacturers website that speaker wire connection was thru a terminal block but it's really cheesy and loose as it's a plugin module(only part that doesn't feel quality at all), add to that how tight the 2 terminals are together and it's begging for a loose wire short. The screw down clamps do need seem to be able to hold the wire very tightly either. Why not use banana jacks like the 200W version as there seems to be plenty of room inside(I doubt the trigger input sees much use). May mod that at some point myself.

I like the internal power supply and the controls on the front. The auto on and off trigger works well. I have not tested it as a speaker amp, just a sub amp. I really have just one complaint. When in stand bye mode the LED changes from green (active) to red (stand bye). The LED is so bright, it is like a red laser pointer in the room. At night it makes the entire room glow. I will end up putting some electrical tape over it, but you can see from my photo with my finger completely covering the LED how it still glows red. I wish there was a way to disable it.

Received this OSD SMP-100 subwoofer amp on January 9th 2020, after looking at different models this one made the most sense. After hooking it up and doing my tests this amp was exactly what I needed to include in my whole house audio system. This sub amp works excellent wired into my receiver and my 4 zone 8 speaker selector switch for my ceiling speakers with a separate not passive but an 8 inch active subwoofer, if it is wired and set up correctly this little amp @ 80RMS 100watts of power into 4 ohms can deliver enough power to shake my whole house at quarter of the volume from watching a movie or playing music it's very clean sound with no hum feedback, it has a phase control to adjust for sub placement, a crossover control so you can adjust and set the low pass to your desire level and an overall volume control to set the desire volume, it will automatically switch off after 15 minutes if no audio signal is detected so no need for you to switch on and off manually. My recommendation is not to use speakers that are more than 8 inch 4 to 8 ohms as stated in the manual. Following a correct set up this little amp will deliver a clean solid deep bass without being out of phase with your system. This sub amp can also be used for powering an in-wall passive subwoofer like the OSD IWS 8 series which I will be doing later.

I wanted a rack mounted amp especially made to play subwoofers. Similar to those made to be inside the speaker boxes. With the basic controls for a sub, such as phase control, lowpass filter and auto turn on. And this amp fits the bill.

Documentation is minimal. The Model number of the amp I got is OSD M13. It's a class AB amp. The owners manual lists power as 150 watts. The Amazon description lists it at 250 watts with a different model number SMP250. Neither say into what load. Looking at OSD website I saw a couple of amps with different model numbers that looked similar and claim to be high current 2 ohm stable.

So I gave it a shot for a dual (4 ohms each) voice coil 12" sub I had laying around. VC's hooked up in parallel to make a 2 ohm load. So far, so good. I haven't played for long periods of time yet. But the AB class amp runs cool and seems to handle the 2 ohm load. And while I don't have testing equipment to rate the power output I did measure the max SPL on my main sub (a 4 ohm 15") to be around 3 DB less than when driven by a Carver M-1.5 600 watts per channel amp.

So all else being equal, power is close to half of the 600 watt into 8 ohm Carver amp. I would not want to compare the max spl using the 12" woofer due to Carver amp not being 2 ohm stable. I burnt out a Carver cube amp, the M-400 playing it into too low of an impedance load.

No damping factor specs, but upon visual and audible inspection, it seems to have good control of motion of speaker.

I just wished it was WiFi controls instead of a ir-remote