I'm working on a speaker project that requires 5 amp channels, so I opted for a Kenwood car amplifier alongside a reasonably priced 600W power supply unit (PSU) from Amazon. I housed the PSU in an ABS project box with ventilation and included an IEC power connector that has an on/off switch and a 10A fuse.
Before hooking it up to the amplifier, I wanted to check its performance. I noticed that the fan kicks on immediately, which was a bit disappointing. I expected it to run only when needed, especially since the lid is currently on. Additionally, I can only adjust the voltage up to about 12.8V, even though it claims to support up to 15V, which is more in line with what a running car would provide (around 14V). The amplifier functions best closer to 14V than 12V.
Lastly, when I turned the PSU off, the LED on the switch remained lit, and after unplugging it from the wall and measuring the output with a multimeter, I found 12V still present, gradually decreasing to around 4-5V over a couple of minutes. Given these observations, I'm hesitant about using this PSU. Should I stick with it, or is it normal behavior? I'm worried a new one from a different supplier might perform similarly. Thanks!
1 Answer
The slow voltage drop you observed is likely due to the output capacitors discharging slowly. This is normal behavior, and they could discharge faster if there was a load connected. The PSU may still be fine.
Could it handle fluctuating loads well, or would that change the discharge rate?