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I just picked up an external (to auto receiver) amplifier with no docs. I'll either use it in the Jeep or the Bimmer to power a subwoofer.
The Jeep's uber system has 2 line-level, subwoofer RCA connectors to go to an amp. Alternatively, the Bimmer's sound system sucks and I may try to power the existing (or a replacement subwoofer) with this amp.
So. The amp has 2 RCA inputs which should be line-level?
The amp labels them "low input".
There are 2 other screw-terminal inputs labeled "high input". Speaker level? I would guess that I'd take the existing amp wires off the Bimmer's subwoofer, connect them to the amp's "high level" input and run a connection from the amp's 'speaker' output terminals to the subwoofer. Have I got that right?
One more. The power connector has a 'rem' terminal in addition to the power connections. Is this an on/off function? If so, how is it connected? To system + to power up?
TIA
question Re; automotive audio amp
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#2
Shawn 
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Posted 13 May 2006 - 05:15 PM
QUOTE
The remote terminal requires a minimal amount of power. Most HUs supply .25A to that wire, and that can turn on at least a 2-3 amplifiers
So long as there is no voltage being given to the remote terminal, the amplifier will not draw power from it's main +12v line.
So long as there is no voltage being given to the remote terminal, the amplifier will not draw power from it's main +12v line.
That's from MP3Car.com.
With regard to the hi and low inputs, at first blush I would have thought of high and low impedance levels. I suspect you are correct though; but if you stop by a local car audio shop someone is sure to offer 30 seconds of help to remove any anxiety about blowing the whole thing up.
This post has been edited by Shawn: 13 May 2006 - 05:15 PM
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Skibum
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Posted 13 May 2006 - 07:37 PM
QUOTE (Jay @ May 13 2006, 08:21 PM)
Thanks Shawn & Ski.
It's a RadioShack Optimus 50-watt unit 12-1970 RS part no.
I paid $5.00.
It's a RadioShack Optimus 50-watt unit 12-1970 RS part no.
I paid $5.00.
That is Jeep, or circular bin comaptible.. it is not BMW centric....
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Jay
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Posted 13 May 2006 - 07:46 PM
Ski. Expound?
I'm interpreting that yes, the "low level" (line-level?") inputs will accept the Jeep's line-level subwoofer outputs and drive a speaker.
I'm lost on the Bimmer part. You mean that the "high level" inputs do not accept a speaker level input? I suspect you mean something different.
I'm interpreting that yes, the "low level" (line-level?") inputs will accept the Jeep's line-level subwoofer outputs and drive a speaker.
I'm lost on the Bimmer part. You mean that the "high level" inputs do not accept a speaker level input? I suspect you mean something different.
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Jay
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Posted 14 May 2006 - 06:52 AM
QUOTE (Shawn @ May 13 2006, 11:15 PM)
Sorry Jay - "HU" = head unit (the in dash part of a car stereo).
got it
The battery is in the rear, close to the subwoofer. I'd probably just run a power line with a separate switch to the amp. I have no idea as how to tap into the HU.
This post has been edited by Jay: 14 May 2006 - 07:01 AM
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Jay
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Posted 14 May 2006 - 06:58 AM
QUOTE (Skibum @ May 14 2006, 06:33 AM)
What I mean is that I would never even consider using a Rat Shack amp in a BMW.
I'm sure you wouldn't.
Nevertheless, am I right re; the high level input terminals are for speaker input?
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Skibum
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Posted 14 May 2006 - 08:42 AM
Yes.. HOWEVER
You need to be extremely careful when trying to use a floating ground output of a radio into a crap amp like that. You need to be sure that the high level inputs float above ground and that left and right are not commonly grounded. You run the risk of frying the radio. Not to mention the BMW radio likely has at least that amount of power going to any separate subwoofer.
Stay away...
You need to be extremely careful when trying to use a floating ground output of a radio into a crap amp like that. You need to be sure that the high level inputs float above ground and that left and right are not commonly grounded. You run the risk of frying the radio. Not to mention the BMW radio likely has at least that amount of power going to any separate subwoofer.
Stay away...
#13
Jay
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Posted 14 May 2006 - 11:38 AM
good point. I totally forgot automotive speakers are at chassis ground on one side - it's been a loooong time!
The Bimmer sound system is crap and I think the "subwoofer" is rated at 30 watts. Looks like the Jeep gets a sub.
The Bimmer sound system is crap and I think the "subwoofer" is rated at 30 watts. Looks like the Jeep gets a sub.
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Posted 15 May 2006 - 04:30 PM
QUOTE (Jay @ May 16 2006, 07:16 AM)
Well, more than that annoying engine growl.
Annoying engine growl in a Bimmer?...............
By the way, as Ski mentioned, I'd be cautious with wiring in your car. Bimmers dont like strange electricals being put in them. When I got the(non-bmw) navigation system installed, the shop had a bmw tech come over to play with the wiring.
Remember,........used ECU=$400-$500.........
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Jay
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Posted 15 May 2006 - 04:41 PM
seriously (I hate that) I'll have a pro do it.
Last time I mod'd a car sound system was adding an 8-track to my 57 Chevy. Old-timers on this board may remember the pic
And I DO appreciate the input
Last time I mod'd a car sound system was adding an 8-track to my 57 Chevy. Old-timers on this board may remember the pic
And I DO appreciate the input
This post has been edited by Jay: 15 May 2006 - 04:43 PM
