Keiga KG-5150 signal sense

[Gerhard]

I have one of these in my PC speaker setup: Keiga KG-5150. Problem is, it shuts off when the audio level is too low, even if there is a lot of bass in the signal. I use a miniDSP so the sub only gets bass frequencies. I don't know if the circuitry that does the signal sensing requires the full audio band to work properly?

Could someone who knows these amps and their circuitry please help me by explaining how to modify it to do either of two things:

1. Bypass the signal sensing circuitry altogether (I can switch the amp on and off as needed). I guess I can just bypass the relay that does the switching?
2. Increase the sensitivity of the circuitry to switch on with a lower signal level - which is my preferred solution.
3. Increase the time the amp stays on after the signal stops.

Thanks,
Gerhard