idealrides

I have a 10" JL sub, powered by an Alpine 300w amp which I installed in my s4 a while ago. I was using a high-low converter running off the deck speakers, which worked OK, but recently I tapped the lineout directly from the Bose amp in the trunk because I wanted a more linear response to the volume (i.e. with the converter there was too much bass at low volume and not enough at high volume) and that problem was solved, but...

every time the alpine amp turns on, (which happens 5 seconds after it gets the signal) it sends a pulse OUT of its line-IN which then back-feeds into the bose amp and makes a "thud" sound (proportional to the bose volume) through the bose speakers. I could prevent the thud by turning the volume all the way down when the alpine turned on.

Has any else had this problem? Could I prevent it using a diode?

Thanks

P.S. It was so annoying that I went back to the converter for now.

TEDS4

I had the same set up as you (bose line tap to sub and amp) and had a very quiet turn on "pop" sound. I never experienced it going through my bose speakers- it was only isolated to the subs. I would check your remote lead and grounding, to make sure there is a soild connection. Im sorta amazed y your amp takes so long to turn on? The amp i had running my subs ( sony mobile es amp) only took a second or less to turn on. When i would turn on my system, i would just keep the volume low and then turn it up, to avoid a "pop" - just as you say you do. I know that most very hi end amps have a "soft turn on" feature wich illiminates this "pop' or thud. I havent got my new amp yet, but it has this feature.

hope this helps

peace

idealrides

I thought it was my sub that was popping, but I disconnected it from the amp and I still got the pop! It could only have been coming from the bose speakers (the rear ones, because I took the line level signal of the left and right rear).

And when I had this amp and sub in my last car, running of a line-out directly from an Alpine headunit, it would never pop at all, and it would only take a second to turn on. Maybe I need to try a different grounding point.

TEDS4

well im not completely sure - but i know i does come from the subs- possibly from the speakers - when i was installing my front speakers - before i hooked them up i turned on my stystem to listen and the subs did make the pop - but im not sure if that is the only place - as i didnt have my fronts hooked up - right now i still hear the pop - but i cant tell if its comming from the speakers or the subs. Im confused now. anyways...

That is interesting that your amp didnt make any such noise and turned on normally before - i agree you should check your grounding and also make sure all connections are secure - check your remote wire also.

hope this helps may the force be with you. haha ( i just was watching the movie)

peace