PA D5000.5 Amp Hiss (even when RCAs unplugged; disappears when sound is played)

[fleas2016]

Hi Guys! I need advice. I just received my PA D5000.5 amp from Amazon and installed it just a few hours ago. Before the installation of the PA D 5-channel amp, I had another aging temporary 4-channel non-polk local amp to power my MM6501 seps (front) and DB651 coaxials (rear). With the temp amp, I had no noise besides the high-pitched powering off sound when amp is turned off

But with the PA D5000.5 amp, I'm getting some hiss/whine even if:

1) Radio is OFF (same scenario if my volume is set to 0 or fader/balance set to extremes)
2) RCA inputs are NOT plugged to the amp
3) Engine is OFF (I get engine whine in addition when engine is on).

Here's the thing: when I turn on the radio and adjust the radio volume/fader/balance so a speaker plays a sound. The hiss from that particular speaker is gone even I turn the radio off afterwards (and on again) or just the particular speaker using fader/balance controls. This is true even when I start the engine

But any speaker that hasn't played a sound since initially switching the car from OFF to ACC will have the hiss/whine

The hiss doesn't increase with the volume.

NOTE: My remote on wire is connected to the car's ACC so the amp turns on immediately. Unfortunately, my factory head unit doesn't have a remote out.

But then again, with the temp amp, it doesn't matter, I don't have this noise at all.

What's wrong with my all Polk setup?

[F1nut]

Try posting this in the "On The Move" section below.

[fleas2016]

OK, done. Thanks!

I'll update this thread with new information anyway just in case the Polk support staff will check this:

[UPDATE] I have some more points that I found out about my issue:

1. Let's say the car is on ACC with my HU off and I am getting this buzzing sound. If I open the driver-side door, I get this alarm that my key is still in the keyhole. Pretty normal, right. But once I close the door, the alarm stops.. AND so does the buzzing from speakers

2. After two hours of driving with stereo on (moderate levels most of the time with some elevated levels towards the end), I checked the amp. The PA D5000.5 is hot to the touch (not scalding but I can't keep my palm on it for more than 3 seconds). Now, this is a class D amp and I believe my temp amp is a class A/B amp and its freaking huge, but I never felt it this hot.

[fleas2016]

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