Amp upgrade questions

tgxmike · 07-16-2010, 02:17 PM

OK I've been doing a ton of research on putting a new amp in my 2009 128i (non-premium) HiFi. I've put more than 12 systems into cars already, but never a BMW. So I have some questions to those of you with experience.

I'm going to start by just upgrading the amp. I'll replace/add subs later if needed. And maybe do the door speakers later.

I am debating between 2 methods, and maybe someone has tried each and can comment. I would prefer method 1 as it is less hardware and wiring mess.

Method 1: Use a 4 channel amp with high-level inputs, then use the low level output to a second amp. Amp #1 would run the 4 mid/tweeter pairs, and amp #2 would run the subs (under the seats) see pic below

I considered the Alpine MRP-F300, can I use the high-level inputs and low-level outs to the second amp at the same time?? This would eliminate the need for a line converter (Like the LC6i)

Anyone else use this amp before??

I will also have no extra EQ options with this method...

Method 2: Use line converters, not sure what I'll use for a line converter but options range from $30 (PAC) to >$500 (Audison Bit one.... drool). Probably go with the LC6i.

This is more expensive and has a lot more RCA cabling required (I hate RCA cables, they alway pick up noise.) But I can have much better tuning capabilities.

Also does anyone know if someone makes the adapter to fit on the end of the connector at the amplifier (basically the adapter in the amplifier)? Can I assume since I have not seen anyone with the adapter, it is proprietary?

CentralPA E82 · 07-16-2010, 03:27 PM

The 2009 HiFi is fairly user friendly for an aftermarket amp. The signal to the factory amp is not processed (full-range) essentially a 5V preout. You can tap the lines into the amp and use an RCA adapter (search JL Audio for the speaker to RCA). The processing is done in the amp rather than the head unit. The 2010 and newer cars are much more complicated. Be thankful you have an '09. If you need additional info there a few guys here that can elaborate (VP Electricity and Technic are good sources).

tgxmike · 07-16-2010, 06:54 PM

I guess my only real question is can you use the high level inputs and the preout to a second amp, instead of using something like the LC6i?

I did miss that the stock unit has 5V output. This makes conversion to RCA much easier (If that is necessary).

07-16-2010, 02:17 PM	#1
tgxmike Second Lieutenant 18 Rep 293 Posts Drives: '21 M2C 6MT, '21 Charger Scat Join Date: Feb 2010 Location: Boise, ID iTrader: (0) Garage List 2021 BMW M2 [0.00]	Amp upgrade questions OK I've been doing a ton of research on putting a new amp in my 2009 128i (non-premium) HiFi. I've put more than 12 systems into cars already, but never a BMW. So I have some questions to those of you with experience. I'm going to start by just upgrading the amp. I'll replace/add subs later if needed. And maybe do the door speakers later. I am debating between 2 methods, and maybe someone has tried each and can comment. I would prefer method 1 as it is less hardware and wiring mess. Method 1: Use a 4 channel amp with high-level inputs, then use the low level output to a second amp. Amp #1 would run the 4 mid/tweeter pairs, and amp #2 would run the subs (under the seats) see pic below I considered the Alpine MRP-F300, can I use the high-level inputs and low-level outs to the second amp at the same time?? This would eliminate the need for a line converter (Like the LC6i) Anyone else use this amp before?? I will also have no extra EQ options with this method... Method 2: Use line converters, not sure what I'll use for a line converter but options range from $30 (PAC) to >$500 (Audison Bit one.... drool). Probably go with the LC6i. This is more expensive and has a lot more RCA cabling required (I hate RCA cables, they alway pick up noise.) But I can have much better tuning capabilities. Also does anyone know if someone makes the adapter to fit on the end of the connector at the amplifier (basically the adapter in the amplifier)? Can I assume since I have not seen anyone with the adapter, it is proprietary? Attached Images
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07-16-2010, 06:54 PM	#3
tgxmike Second Lieutenant 18 Rep 293 Posts Drives: '21 M2C 6MT, '21 Charger Scat Join Date: Feb 2010 Location: Boise, ID iTrader: (0) Garage List 2021 BMW M2 [0.00]	I guess my only real question is can you use the high level inputs and the preout to a second amp, instead of using something like the LC6i? I did miss that the stock unit has 5V output. This makes conversion to RCA much easier (If that is necessary).
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07-16-2010, 03:27 PM	#2
CentralPA E82 Rookie 7 Rep 264 Posts Drives: 2009 128i Join Date: Apr 2010 Location: New Cumberland, PA iTrader: (1)	The 2009 HiFi is fairly user friendly for an aftermarket amp. The signal to the factory amp is not processed (full-range) essentially a 5V preout. You can tap the lines into the amp and use an RCA adapter (search JL Audio for the speaker to RCA). The processing is done in the amp rather than the head unit. The 2010 and newer cars are much more complicated. Be thankful you have an '09. If you need additional info there a few guys here that can elaborate (VP Electricity and Technic are good sources).
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