Quote:
Originally Posted by HIS4
Can you crank up the input/output gains on the DQXS so you can minimize the gain on the PDX amps? That might help minimize the hiss.
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The issue is beyond that... the hiss is there without any PDX inputs and at the absolute minimum gain. The last thing that I have not tried yet is moving the main 12v line from the OEM distribution to the positive terminal straight.
The main reason that I have to go with the OEM remote turn on instead of using the Cleansweep
signal sensing mode was that I was also noticing some faint whine at just start up, then 3-5 seconds later was gone. Coincidentally those 3-5 seconds were the time that the signal sensing took to turn the whole system on
and audio start playing after sensing the OEM outputs.
I did not notice that whine when I wrote my initial post because I was not using the signal sensing mode, I was using the
ignition sensing mode with the OEM CD Changer 12V line as the trigger. That OEM line turns on and off
almost like an ignition line, however the turn off time is very irregular and sometimes it took more than an hour to really turn off and the amps were getting very hot by being on for so long. So I started using the signal sensing mode to avoid this issue... and then the whine appeared.
By removing that signal sensing feature (flipping a switch) and making the Cleansweep turn everything on with OEM antenna switching signal (pin 13) in the ignition sensing mode all the aftermarket equipment is turned on immediately at the same time my iDrive is booting up, and the whine is gone. Now the system turns on
and off exactly like factory and no more heat issues...
That also tells me that the aftermarket equipment has some noise suppressor circuits indeed, and most probably the hiss is induced to the 12V line in that OEM distribution block slot by whatever OEM devices are plugged in beside it.