Hi gang,
I'm having a weird problem with my car system and maybe someone can help me
ID the cause before I just go and replace everything needlessly. When I turn
on the system, it *sometimes* takes as long as 20 or 30 seconds to start
playing through the speakers. *sometimes* it thumps when you turn it on,
sometimes not. Sometimes it will rumble very loudly and then start playing.
Even after it starts, I cant turn it up at all or it will cut out on the
loudest part of the program material, even if its just talk radio.
I tend to keep car audio stuff for a long time, so maybe it's the age of
some of my stuff catching up with it. Here's what's in the car, a 2002
Toyota eCHO. A lot of the same stuff has travelled with me through a few
vehicles, including a Kenwood 10 CD changer thats at least 10 years old.
Kenwood head unit, one set of preouts
Kenwood 5 band EQ, three sets of preouts, front, rear and sub
Kenwood 10 CD changer.
I just replaced all this stuff with a new Kenwood HU and the problem didnt
go away, so it isnt this stuff.
the front speakers are kenwood separates in the door and dash. These are
only about a year old.
rear deck is a pair of Kenwood 7x10 triaxials. They still sound great even
though they are ancient.
subwoofer is a single boston Acoustics 12" in a large ported custom
enclosure.
The front and rear speakers are pushed by a PPI Sedona series 460 amp.
(4x60w RMS) This amp is pretty old and I think it may be crapping out on
me. I hope not, since it's been a great performer for years and years. I
used to bridge two channels and push the sub (200w) and power the rears with
the other two 60w channels. The fronts were head unit powered for a long
time (useless) then I bought a crappy 2x40w pioneer amp to push them
(slightly less useless but still crap). Finally I bought a US Acoustics
USB2100 to push the sub (bridged to 300W) and started using the PPI to power
the front separates. I used the Xover output of the PPI to send the LP
signal to the US Acoustics sub amp. It sounded incredible.
I used this system for a month or so before this stupid problem popped up.
Here's a couple things that may or may not be relevant:
The problem started happening during a long string of very hot days..over 90
degrees. I drive in my car for a living, so the system is used about 8
hours a day, sometimes turned off and on only 5 minutes apart. I thought it
might be heat related so I dropped the back seat backs to let AC air in the
trunk (amps are mounted on the sub box facing the back of the rear seats
with about 6-8" of airspace).
I should also mention that I know the power feed is inadequate. Its only an
8ga wire feeding 540 watts of amp. I am in the middle of putting in a 4ga
wire split between the two. Both amps are grounded (8ga for each) in the
trunk to a big fat screw driven straight into the metal of the body in the
trunk structure.
the questions: could this inadequate power supply have cooked the old PPI?
Is this weird fading in and rumbling/thumping a symptom of an amp that's
going south? I am upgrading and redoing all the wiring because i think I
may have to replace the amp. I am happy with the US Acoustics stuff for the
$$$ and will probably go with a USB4065 to match the USB2100 since I will be
losing the Xovers in the PPI.
ANy info is welcome. Thanks for your time and knowledge.
~daxe
http://www.snakefoot.com