Amplifier might be a dud?

[Romans5.8 10+ year member]

Hey folks!

So I'm upgrading the stereo on my motorcycle. I've replaced the factory 5.25" cheap speakers with a pair of Polk MM651 6.5" speakers, and I'm installing a Rockford Fosgate PBR300X2 Amp. I'm using high level inputs for the Rockford amp.

From the factory, the speakers plug in to a lead which then plugs into an inline disconnect that then runs through a wiring harness to the factory stereo. I took that lead, cut off the speaker-side connector and soldered it to the Amp's "input" connector. Effectively making a custom 'cable' that connects on one end to the bikes proprietary speaker connections, and on the other end to the amps proprietary input end.

If I connect the LEFT side input to the bike (and it doesn't matter whether I connect the left side input to the left OR right output of the bike), it plays just fine; through one speaker. If I connect the RIGHT side input to either side, the amp shuts off (I'm not using a remote wire, this amp supports switching on when it receives that high level signal). If I connect both together, it pops and cuts in and out, going in and out of protection mode.

My first instinct was a bad solder joint, so I cut the soldered connection and just temporarily twisted the wires together. The behavior was exactly the same.

Again, it doesn't matter which side of the OEM stereo's output I connect it to; but it will only work if connected to the amp's left side input; and the right side is unplugged.

Is there something I'm doing wrong here? Or does this sound like the amp is bad and needs to be sent back?

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[hispls 5,000+ posts]

I can't really follow what you're trying to say, but is it possible there is a problem with the factory wiring to the speakers or the speakers themselves on the problem side?

Have you given the good side signal to either side of the amp?

 

[Romans5.8 10+ year member]

No, it's not an issue with the output side or the speakers. As I said in the OP, I did run both sides of the input to the left side of the amp; and both sides work.

I can get either speaker to work by switching which side they're connected to. And the amp works if the LEFT side input is connected to EITHER side of the bike's output.

I know this is kind of confusing; let me try to break it down.

LEFT OEM Output to LEFT Input WORKS

RIGHT OEM Output to LEFT Input WORKS

LEFT OEM Output to RIGHT Input DOES NOT WORK

RIGHT OEM Output to RIGHT Input DOES NOT WORK

BOTH OUTPUTS to BOTH INPUTS DOES NOT WORK

So, in essence, the amp only works if the left side input is receiving a signal exclusively; and it doesn't matter whether it's receiving that signal from the left or right output of the amplifier.

 

[hispls 5,000+ posts]

No, it's not an issue with the output side or the speakers. As I said in the OP, I did run both sides of the input to the left side of the amp; and both sides work.
I can get either speaker to work by switching which side they're connected to. And the amp works if the LEFT side input is connected to EITHER side of the bike's output.

I know this is kind of confusing; let me try to break it down.

LEFT OEM Output to LEFT Input WORKS

RIGHT OEM Output to LEFT Input WORKS

LEFT OEM Output to RIGHT Input DOES NOT WORK

RIGHT OEM Output to RIGHT Input DOES NOT WORK

BOTH OUTPUTS to BOTH INPUTS DOES NOT WORK

So, in essence, the amp only works if the left side input is receiving a signal exclusively; and it doesn't matter whether it's receiving that signal from the left or right output of the amplifier.

So what's going on with the right OUTPUT from the amp? Do you have a speaker you can wire right next to the amp to test? this will rule out an issue (short) with the right hand side speaker or OEM wiring in the vehicle.

If a test speaker with wire you can see does not work on the right amp output it's a problem with the amp, otherwise it's either the speaker or factory wiring on the right side causing the amp to protect.

 

[Romans5.8 10+ year member]

Thanks!

So, I did swap both speakers. It's in a motorcycle fairing so the speakers are only a foot from the amp. Swapping the speaker leads didn't change anything; except which speaker played. I'm not using the vehicles OEM wiring out to the speakers. The Vehicles OEM wiring is used for the high level input side; and I believe swapping them would show that it's working fine. Plus, it works fine connected directly to the speakers (just, of course, not amplified). I did that to test the speakers, too.

I guess the amp is a dud; I was hoping there was one more thing I could try, or one issue out there.

 

[hispls 5,000+ posts]

Thanks!
So, I did swap both speakers. It's in a motorcycle fairing so the speakers are only a foot from the amp. Swapping the speaker leads didn't change anything; except which speaker played. I'm not using the vehicles OEM wiring out to the speakers. The Vehicles OEM wiring is used for the high level input side; and I believe swapping them would show that it's working fine. Plus, it works fine connected directly to the speakers (just, of course, not amplified). I did that to test the speakers, too.

I guess the amp is a dud; I was hoping there was one more thing I could try, or one issue out there.

Process of elimination suggests it's a bum channel on the amp.

 

[Romans5.8 10+ year member]

That's what I was afraid of. Okay; back to Amazon!

 

[Boomin_tahoe 5,000+ posts]

I just installed these very same speakers (Polk) in my Tahoe over the past few days. I'm wondering how you were able to manage to put a 6.5" speaker into a 5.25" opening?

 

[Romans5.8 10+ year member]

I just installed these very same speakers (Polk) in my Tahoe over the past few days. I'm wondering how you were able to manage to put a 6.5" speaker into a 5.25" opening?

There's a guy who 3D Prints these adapters specifically for this motorcycle. The mount where the factory grill mounted and provide a standard 6.5" mounting platform.

Not my bike or my speakers, (In fact; one big reason I went with the Polk speakers, is that their grill is not obnoxious, fake chrome, etc. etc. like so many marine speakers), but you get the idea. Pictured here is the Kawasaki Vulcan Voyager. I have a Kawasaki Vulcan Vaquero, similar models with identical fairings. This same guy also sells an amp mounting bracket; so it's all pretty easy and straightforward.

 

[Boomin_tahoe 5,000+ posts]

There's a guy who 3D Prints these adapters specifically for this motorcycle. The mount where the factory grill mounted and provide a standard 6.5" mounting platform.

Not my bike or my speakers, (In fact; one big reason I went with the Polk speakers, is that their grill is not obnoxious, fake chrome, etc. etc. like so many marine speakers), but you get the idea. Pictured here is the Kawasaki Vulcan Voyager. I have a Kawasaki Vulcan Vaquero, similar models with identical fairings. This same guy also sells an amp mounting bracket; so it's all pretty easy and straightforward.

That's what I figured. So since vehicles differ from motorcycles, have no idea how much room there is on a motorcycle. The only way I thought was to make a baffle. Pretty much what you just stated, just worded differently. The Polk set does come with some hard plastic grille covers....I left them off as the factory doors provide grilles already, thank god. They're not chrome, fyi. Even the newer set of MM6502 has some cheesy grilles. That particular model replaces the MM6501 which is discontinued.

 

[Romans5.8 10+ year member]

Thanks! Yeah, I know what they look like and that they come with them. Like I said, that was a big determining factor in why I chose them. They are already installed (I'm just not home to take a picture); I'm just waiting the amp install. Well, now, awaiting a replacement amp.

 

[Boomin_tahoe 5,000+ posts]

Read that wrong, sorry. My computer was messing up at the same time I was reading and typing. Re boot it and see how it does. Dam computers....like women cant live w/o them, can live with them.

 

[Romans5.8 10+ year member]

I'm just hoping this fixes this problem! What an annoying issue! And I had to tear into the bike so much to run the wiring that I've got a few hours of ratchet-wrench time ahead of me just to get the darn thing running again once I get this stereo squared away. This turned into quite the project!

 

[Boomin_tahoe 5,000+ posts]

I'm just hoping this fixes this problem! What an annoying issue! And I had to tear into the bike so much to run the wiring that I've got a few hours of ratchet-wrench time ahead of me just to get the darn thing running again once I get this stereo squared away. This turned into quite the project!

lol yeah...I know not funny but sometimes simple things in life turn into a week long project. My Polks took about 4 days to do. I kept running into snags so I allowed myself some extra time in case things like so happened. Just finished it yesterday. I have 3 vehicles. Wanted to make sure I have at least 1 running to go to a store or something just in case while I was working on the other.

 

[Romans5.8 10+ year member]

lol yeah...I know not funny but sometimes simple things in life turn into a week long project. My Polks took about 4 days to do. I kept running into snags so I allowed myself some extra time in case things like so happened. Just finished it yesterday. I have 3 vehicles. Wanted to make sure I have at least 1 running to go to a store or something just in case while I was working on the other.

Yeah, the bike is a toy. A really really fun toy! But, nothing that can't easily be left in dozens of pieces all over the garage.

I just hope I don't have any bolts leftover once it's all put together.

Thankfully it's a fuel injected motorcycle (well, they all are now). That significantly reduces the complication of removing the fuel tank; which gives me room to run wires back to the battery and ground.

I have done a LOT of soldering over the last few days. Splicing an amp in between an OEM head unit and some aftermarket speakers. Phew!