OSD Audio SMP500 Mono-Channel Class D Subwoofer Amplifier with Onboard DSP 400W 4 -8 Ohm

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.

Product came from the USA so it took a little time but after receiving and installing it initially seemed to work OK. However, the trigger function is a problem. Connecting to an Arcam AVR20 Integrated Amp to sync power on/off. The trigger functions fails to operate, indeed there is a "buzzing/fizzing" sound coming from the SMP500 and sounds like a short-circuit... I immediately pulled the power cord fearing damaged to either my AVR20 or the SMP500. I checked the polarity, voltage and current of the trigger cable and AVR20 output and it is within spec ( AVR20 DC +12v 70mA, 3.5mm jack, tip +). and correctly wired. In the "On" mode, it works as expected but the "Music" mode should turn off when a signal is not present and on when a signal is detected, but it's unreliable, sometimes it does, others it doesn't. I attempted to find a support link to the manufacturer (OSD) but they only offer dealer support. On the Amazon order page there is no option to "ask a question", so I contacted customer service and the only option was to return the product, no help there. I suspect that it has a fault, or the labeling is incorrect (e.g. the + and - symbols are incorrect or specifications are wrong), can you please confirm the the product labeling is correct (+ and - and trigger in/out and switch setting 12v/On/Music). Setting the switch to "12v" and "External Trigger On" in the software setting is what I understand is correct but that can't be confirmed it seems. I have decided to keep the product but am concerned that it will be a problem in the future, a risk. The reason for only two stars is that there is no UK support, to even ask a question of. So after the 30 days Amazon option of return any warranty is useless it seems. Update. Now there's a pulsing noise emitting from the driver, even when the phono isn't connected. This noise is sufficiently load that I can hear it 15 feet away in the primary listening position during the quiet gaps in films/music. For a £600+ device this is unacceptable. Now being returned and reduced to one star, zero if there was an option.

Works well powers my passive subwoofer (same brand) like a movie theatre !

Coupled with the OSD 12” sub and it’s a fantastic sounding amp.

Very pleased. Its works well with my SONOS Amp and it drives my outdoor subwoofer. Great bass in the pool courtyard.