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[DennisG]

Hi All,

I am installing an Arc 125.2 amp on a 2011 Street Glide.  I pulled out the 100 watt amp that comes stock on the CVO and I cut the wires so that I can use the plug. that connected the amp to the harness.  I have everything wired up including the accessory turn on wire from the radio, and it all powers up, works and sounds killer but, when I turn off the head unit the Arc doesn't turn off and you can hear residual noise floor through the speakers and when you turn the radio back on, it of course pops because the power amp is still on.  How do I get the amp to go off when head unit is switched off?

I tried that thing where you remove the jumper from inside and it will supposedly sense the radio but then I blow the fuse to the radio.  Very strange. 

Any ideas?

Thanks

Dennis

[Harleypingman]

Can't answer your question other than to suggest you PM TIF2 (Rich) who had the Arc 125.2 in his bike until the installed the Rockford Fosgate PBR300X4 amp for the front; he's using the Arc 125.2 for the tour pak speakers.

You can also call Iron Cross Audio and ask Tony about the issue.

Another suggestion is to contact Arc and ask them about the remote sense feature blowing the radio fuse.  Arc specifically markets the Arc 125.2 for Harley Davidson applications in their MPAK products.

Carl

[Black Diamond]

DennisG

Let me know what you find out on this. I'm looking to do the same install when the riding seasons over.

JW

[mjb765]

Yes..please post what you find on this.....

[DennisG]

Thanks for the replies guys.  I will post what I find.  The amp sounds great with the Focal spkrs.  Just gotta get it dialed in!  I am gonna check with the car audio shop I bought the amp from.  They do a lot  of bikes there but there have been closed, should open soon

Dennis

[DennisG]

Ok I have it working.  I called arc.  They say the Harley radio does not have a good control wire because it leaves 12 volts on the wire even when you shut it off, so the amp stays on until you shut off bike.  I didn't like that way because if you shut radio off then amp  still runs for no  reason pumping audio noise through the speakers and  if you turn radio back on it would pop.   

He told me to use the high level/speaker ins with the provided connector so that the balanced input could minimize popping. Then he told me to try the audio sensing circuitry by removing a jumper inside. I tried that the night before  and it didn't work but it was because I was using the RCA line ins and sensing circuitry only works on the speaker level ins.  A problem that can occur is that the Harley chip sometimes resets at high volume and the arc sensing circuit sees this as a power down event and will cause the amp to power down and then come back on in 5 seconds or so.  So far it hasn't happened.

Do not use the control wire when using the audio sensing circuit, because when you pull that jumper it changes the control wire in to a control wire out for turning on other amps if you have them.

[Harleypingman]

Glad to see you made progress in finding a solution and that Arc was helpful.

The HK radio's "control wire" you reference:  is that the wire in chamber 12 of the HK's 23-wire connector which is labeled as "accessory enable" in the SESG2 wiring diagram?

Also, the reference to "removing the jumper wire inside," is that a jumper wire inside the amp?

Thanks in advance for your reply.

Carl

[DennisG]

 I have the book out in the garage at the moment so I am unsure of the pin number but  yes, I am referring to the accessory enable wire.  

It is called accessory enable wire from radio but something like amp memory on the factory amp input plug.  

I just cut the wires between the amp and its plug and used the same plug and hardwired it right to the Arc for speaker connections.  Arc comes with small harness and plug for speaker voltage level inputs. I connected that to the "speaker in" wires coming from plug that originally went in to factory amp.

 Ran power and ground right to battery with 8 gauge wire.  Did it right... took tank off and ran it through wire tunnel.   I first tried power and ground wire off plug and it didn't seem to work and it was a compromise on wire size anyway. The Arc manual says to use number 8 wire.

The jumper is a tiny plastic plug that goes over two pins, easy to remove or reinstall. Its about in the center of the circuit board.   I taped the little plug to the top of the amp with clear tape so I don't lose it in case I want to reattach at some point.

Dennis

[Iron Cross Audio]

We're currently testing a 12v out remote line from the HK radio to be used as an amp remote turn on.
We should have it available by the end of Sept.

[DennisG]

Well I was tweaking all the settings on the amp and the sound was not quite right, not much good bass and I had thought that perhaps it was just the inherent nature of the poor cabinets(fairing and lowers).  Or maybe it had something to do with using speaker level outputs into the power amp. 

But I noted that I had decent bass when listening to the side of the bike but when in the middle it would disappear.  This led me to believe that something was out of phase, but I had verified the speaker lines as being correct and I know that I connected the speaker level in plug right.  I took the fairing off again to take a look and lo and behold, when I was connecting the arcs spkr outs to the wires from the plug, in the middle of the night while tired, I inadvertently had the left speaker wires reversed.  It was out of phase!  Good news!  I connected them properly and WOW!  It sounds totally amazing now.  Great bass and fantastic detail.  Those Focal speakers are awesome.  But pricy!  They are so good, they even sound rather impressive when out of phase, causing you to almost be satisfied.  But in phase?   

I put some coaxial spkrs in the lowers but the harley emblem covers the tweeters, so I took my Dremel and ground the plastic out inside the harley emblem. 

It is really fantastic.   This is the stereo that Harley should have put in a $35000 motorcycle from the factory... not that cheap Chinese crap speakers with tiny magnets and amp that runs at 1/2 ohm.

Dennis

[TIF2]

 Ran power and ground right to battery with 8 gauge wire.  Did it right... took tank off and ran it through wire tunnel.   I first tried power and ground wire off plug and it didn't seem to work and it was a compromise on wire size anyway. The Arc manual says to use number 8 wire.

Dennis

You should never ground an amp to the negative battery terminal. This is probably why you are picking up the "noise floor" in the amp when the radio is off. I am using pin 12 from the H/K to power both of my amps ... they are both dead silent when the radio is off. Keep your ground wires within 30" of the amp and ground to solid, unpainted metal.

Since you have already landed the ground wire to the battery, the easiest solution is to remove the connection to the negative battery post and attach it to the "clean ground" lug on the right side of the frame. It is located just below the negative post on the battery on the frame (you'll see it when you look for it). You'll need to remove the battery and the battery tray to access it. There should be enough length on the existing cable to land it there. Although the ground run will still be a little long - it is LOADS better than connecting to the battery. Short grounding runs are done to prevent EMI coupling of other signals and being fed back to the amp, resulting in noise.

Even though you have it "working" I would re-do the ground. It is really killing how clean that Arc can sound. Also, no need to run 8ga wire to the 125.2. The amp is fused on input at 30amps, so 10ga wire is more than sufficient.

Hope this helps

[DennisG]

You should never ground an amp to the negative battery terminal. This is probably why you are picking up the "noise floor" in the amp when the radio is off. I am using pin 12 from the H/K to power both of my amps ... they are both dead silent when the radio is off. Keep your ground wires within 30" of the amp and ground to solid, unpainted metal.

Since you have already landed the ground wire to the battery, the easiest solution is to remove the connection to the negative battery post and attach it to the "clean ground" lug on the right side of the frame. It is located just below the negative post on the battery on the frame (you'll see it when you look for it). You'll need to remove the battery and the battery tray to access it. There should be enough length on the existing cable to land it there. Although the ground run will still be a little long - it is LOADS better than connecting to the battery. Short grounding runs are done to prevent EMI coupling of other signals and being fed back to the amp, resulting in noise.

Even though you have it "working" I would re-do the ground. It is really killing how clean that Arc can sound. Also, no need to run 8ga wire to the 125.2. The amp is fused on input at 30amps, so 10ga wire is more than sufficient.

Hope this helps

Hi

Thanks for your "input"  " (pun intended)


 Let me first say that when I had  some noise in the early stages of my project I had amp gains wide open and the radio was off and connected to the inputs of the amp. At that point I was  connecting the HK speaker outs to the low level RCA line ins as I was trying to minimize going through any padding circuitry and I wanted to ensure that I had plenty of amp gain on the back end to get to necessary volume levels for system without  over driving  the inputs of the amp with too much radio output.  Of course when both of them are off there is no noise and when both of them are on there is a minimal hiss, much lower than the level of program material.  I subsequently realized I don;t need that much gain and turned the amp gain controls down which also quiets the noise floor as well. 



Are you saying that you have both your amps on all the time even when the radio is off? And it is dead quiet?  How high do you have the gain controls on amps?


  IMO it is just not correct to have the power amp on when the preamp is not, which was my initial dilemma.  This is the situation that allows for unwanted noise with the essentially open wire hanging off the input of the wide open amp like an antenna.  Also, if that was the case that power amp stayed on and you wanted to turn the radio on again, it would pop.  A power amp should always go on last or off first. Now that I am using the auto sensing circuit, and it is doing what it was designed to do, all is well.  The system is actually very quiet as long as both the radio and amp are both on.

I guess I don't get how connecting to a ground lug that is 6 inches away from the negative terminal on the battery is going to eliminate noise.  Sending the electricity through a short piece of frame rail is going to filter it?  The battery itself is not creating noise is it? 

Also, I am sure it will work fine with the smaller power leads, but the Arc manual it says both to use larger than 4 gauge wire (yikes! :-) and on another page, 8 gauge.  I had some nice 8 laying around so I used it.

Dennis 

[Harleypingman]

Dennis,

I found this website has a lot of very useful information regarding a variety of audio issues/questions which has proven very helpful when doing various audio mods on the bike since I'm not a tech or audio professional:

http://www.bcae1.com/

Regarding the Arc 125.2 installation, Arc's 125.2 instructions are somewhat contradictory when compared to what they provide with their MPAK Harley-specific packages.  Specifically, the standard Arc installation instructions refer to using 8 ga. wire, but the harness supplied with the MPAK kits uses 10 or 12 ga. wire (I didn't measure the ga. when I used the harness but it's definitely smaller than the 10 ga. wire I used when installing a Rockford Fosgate amp).  I suspect that Arc recommends the larger ga. wire in anticipation of installing the 125.2 in a car where the distance from the battery (+ wire) to the amp is significantly longer than what we have on our bikes.  (Note:  wire ga. selection is a function of the distance from the battery to the amp according to the website link above and other sources of information I've found on the web.)

I can't speak to the "noise" issue except that the ground should be to the bike's frame since the frame is the end of the electrical path; and, the ground wire to the frame should be a short run as a long run may be a source of "noise"
according to the tech's I spoke to at Arc and Rockford Fosgate.  The installation instructions for the RF PBR300X4 amp I am currently using after replacing the 125.2 says to use a ground wire of 30" or less, so I used the ground screw on the upper triple tree.  In hindsight, I'm confident I could have continued to use the ground stud under the seat that I used with the 125.2 since the distance from the amp to the gound stud is not much longer than 30".  Whether you had noise because the amp ground is connected to the battery I have no opinion.  I'm happy to have as little connected to the battery ground terminal as possible with only the battery tender and HD tour pak/saddlebag light kit at the battery's ground terminal.  

Also, the power wire needs to have an in-line fuse close to the battery.  The RF instructions say to have the fuse (25 or 30 amp) within 16" of the battery which I did when I made up the power wire for my RF installation.  The Arc harness supplied with the MPAK kit included a 25 amp fuse located about 12" or so from the battery terminal lug.

As I said, I'm not a tech or audio professional so I've tried to follow the instructions supplied with the various components I've purchased, as well as relying on reputable web sources for more detailed information and explanations.

Carl

[DennisG]

Carl

Thanks for the reply.  The thing that doesn't make sense to me is that the frame is connected to the negative battery terminal with a wire.   Therefore, the frame or the negative battery terminal are essentially the same. So connecting   to either is the same except the frame probably does not conduct electricity as well as the 8 g copper wire does.   The only difference of course is the length of the wire which could mean something.  I wouldn't trust the connection to something that moves like the triple tree, I would at least run the wire to the frame. 

I have a big fuse in the positive wire close to the battery so I am good there. 

Dennis

[TIF2]

It's not the battery (per se) that can be the source of noise, it's the charging system on the positive side of the battery. Some people say it's fine to connect ground directly to the battery, most got away from that practice long ago. I have never seen a mobile amp manufacturer recommend it - mostly because it can couple noise from the charging system. Remember the days of engine whine?

There are 2 ground lugs on the frame. The electrical diagnostic manual refers to the right lug as "clean ground" and the left lug as "dirty ground". Sensitive electrical devices on the bike are tied to the right side lug (ECU, sensors, etc). Other devices (lights for example) are tied to the left ground lug.

My amps are "powered" all the time, because (as you stated) there is no normal "remote on" from the H/K. I don't get any "pop" when I turn the radio on, nor do I get any noise from the amp(s) when the radio is off. As for my gains, I don't remember where they are set. I dialed them in based on sound quality and didn't worry about how much or how little the gain was adjusted. If I had to guess, I am probably at 25% or so. Front amp gains are set different than the rear amp due to different performance specs of the speakers.

Remember, gain adjustment on an amp doesn't adjust an amplifiers output - it adjusts the sensitivity level of the amps input. Dialing in the gains is usually a balancing act of providing maximum output power without introducing any additional distortion by the amplifier itself.

I'm glad you're happy with your project. If it were me, I would move the ground from the battery post and land it on the "clean" lug on the right side of the frame   . But that's just me ... as long as you're happy with the install that's all that is important.