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Discussion Starter #1
Been away from the site for a wee while and doing a catch up, it struck me how many folk are suffering the alternator whine in their audio devices. It's possible to completely remove the buzz the alternator puts onto the electrical system by making a filter to clean the alternator output. It's pretty simple to do, costs little and uses common filtering technique using capacitors and inductors. To do this you'll need two 2.2uF capacitors - the type often sold in auto parts stores for clipping to the alternator of automobiles - and two inductors (chokes) - the ferrite type often used for clipping around a cable to block RF interference.
The buzzing sound is produced by either alternating current or pulsating direct current superimposed on the main battery cable from the alternator. The principle is straightforward, capacitors pass AC or DC pulses and the chokes block AC or DC pulses. By combining the two, the AC/DC pulses can be forced to travel to ground and so removed from the bike's power system.

The main cable from the alternator will need to be lengthened to accommodate the chokes because the cable needs to take one turn through one choke and there isn't enough free length in the bike's power cable to do this. About a foot of correct size power cable and some eye terminals will be needed plus one nut and bolt for fastening the original cable to the new piece and also some shrink sleeving to insulate that joint.

Before starting, disconnect the negative battery connection from the battery - this is important!

The method:
Make up one end of the new extension cable by soldering on one eye terminal and also solder into this terminal the cable of one of the capacitors.
Remove the main power cable from the alternator, pull the rubber boot from it and slip over the cable one of the chokes and two pieces of shrink sleeving.
Tightly bolt together the new cable and the original cable using the nut and bolt through the eye terminals.
Slip one piece of shrink sleeving over the terminals and shrink it, slip over the second piece and shrink that also to ensure plenty of insulation of the terminals.
Slip the second choke over the extension cable, take the cable back over the choke and through it a second time so as to make a single turn through the body of the choke.
Trim the cable to length, fit the original rubber boot over it and also pass the end of the cable from the second capacitor through the boot.
Solder eye terminals to the main cable and the capacitor cable.
Push the extra length of cable in behind the alternator and reconnect the new length of cable and the capacitor terminal onto the output terminal screw of the alternator and then refit the rubber insulation boot.
Both the capacitors tags need to be fixed to a good ground connection. Any convenient screw or bolt will do. Some alternators have a boss on their side that appears to do nothing so a hole can be drilled through it and the capacitors bolted to it.
Reconnect the battery ground cable.

The operating principal is simply that the AC/DC pulses run to ground through the first capacitor because the choke resists it flowing along the cable, nothing is ever perfect so the second capacitor and choke do a clean up of any remaining AC or DC pulses.
 

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Or you can buy the ready made "plug and play" part from J and M Audio, like I did.........works a charm, comes fully assembled and plugs in under your left side pocket in seconds.

Cheers!

T.
 

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Thanks for posting. I would like to see pictures showing mounting and so on. Looks like wire gauge should be AWG 6 to be safe, although 10 gauge might be ok.
Ron
 

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Discussion Starter #4
Or you can buy the ready made "plug and play" part from J and M Audio, like I did.........works a charm, comes fully assembled and plugs in under your left side pocket in seconds.

Cheers!

T.
Yes, you could do that but then you'd only clean up the supply to the connected device rather than to the whole bike electrical system.

I'm pleased you're happy with your system. :thumbup:

Cheers!
 

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Very nice write-up! :thumbup:
 

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Sounds great, Someone should start selling those things :thumbup:
 

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Thanks for posting. I would like to see pictures showing mounting and so on. Looks like wire gauge should be AWG 6 to be safe, although 10 gauge might be ok.
Ron
+1 on the pics. :thumbup:

Nice write up, but I know just enough about electricity to be dangerous. I think I got it, some pics would really help. I've been fighting this buzzing in the intercoms sense I bought the bike. I tryed the additional G1 to G2 ground wire, helped a little.
 

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Discussion Starter #9
+1 on the pics. :thumbup:

Nice write up, but I know just enough about electricity to be dangerous. I think I got it, some pics would really help. I've been fighting this buzzing in the intercoms sense I bought the bike. I tryed the additional G1 to G2 ground wire, helped a little.
Okidoke. When I did this I wasn't imagining it would be of interest so I didn't take any pics. When it's all done there is nothing to see except the capacitors because the extra cable just pushes in behind the alternator before the alternator connector is screwed down. If I get back in there for any reason, I'll take a couple of snaps.
 

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The previous post is correct in that this is a nice writeup. It's always useful to have another tool to solve problems.

The proper strategy in solving noise problems however should always be to eliminate the cause of the noise before trying to filter it. Sometimes poor design or incompatibility requires the use of a filter. But on the Goldwing, the cause of a majority of alternator whine issues is bad grounds. (except for the aux input ground loop issue and the cruise issue.)
 

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Discussion Starter #11
.... Goldwing, the cause of a majority of alternator wine issues is bad grounds. (except for the aux input ground loop issue and the cruise issue.)
Sorry Larry but I disagree - by definition an alternator produces alternating current where the rectifier diodes invert the negative going portion of the wave. Consequently, the DC output is bumpy DC and, although the alternator contains a small smoothing capacitor, the battery is used to smooth the output, which it does but not completely. The remaining pulses on the system vary with engine speed (alternator speed) and produce the buzzing sound in audio equipment. I guess you could consider the alternator as not a suitable power source for audio equipment but they're here to stay so we need to deal with their shortcomings.

Poor grounds may be a factor where poor grounds exist but chasing non-existent poor grounds is a waste of time (obviously). Ground loops can be a source of interference but they are influenced by electrical noise on the system so if the base system contains electrical noise, getting rid of loops is still leaving the underlying problem.
 

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Ground loops

Sorry Larry but I disagree - by definition an alternator produces alternating current where the rectifier diodes invert the negative going portion of the wave. Consequently, the DC output is bumpy DC and, although the alternator contains a small smoothing capacitor, the battery is used to smooth the output, which it does but not completely. The remaining pulses on the system vary with engine speed (alternator speed) and produce the buzzing sound in audio equipment. I guess you could consider the alternator as not a suitable power source for audio equipment but they're here to stay so we need to deal with their shortcomings.

Poor grounds may be a factor where poor grounds exist but chasing non-existent poor grounds is a waste of time (obviously). Ground loops can be a source of interference but they are influenced by electrical noise on the system so if the base system contains electrical noise, getting rid of loops is still leaving the underlying problem.
Unfortunately getting a clean power supply also leaves another underlying problem which is the voltage differential between the ground points.

Ground loops are a problem even with very high quality power sources such as professional audio equipment. The only way to eliminate the problem with ground loops is to have a single ground potential for the system and zero resistance conductors connecting the circuit to the single ground point. Since we have resistance in our conductors and do not have a uniform potential for the "ground" in the system, we need ground isolators because we will always have potential differences at the ground points. Admittedly, noise in the system will make a ground loop problem worse, but eliminating the noise in the power supply (alternator in this case) will not eliminate the problem of the ground loop since you will still have ground current causing a voltage drop across the various ground points in the circuit.
 

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Sorry Larry but I disagree - by definition an alternator produces alternating current where the rectifier diodes invert the negative going portion of the wave. Consequently, the DC output is bumpy DC and, although the alternator contains a small smoothing capacitor, the battery is used to smooth the output, which it does but not completely. The remaining pulses on the system vary with engine speed (alternator speed) and produce the buzzing sound in audio equipment. I guess you could consider the alternator as not a suitable power source for audio equipment but they're here to stay so we need to deal with their shortcomings.

Poor grounds may be a factor where poor grounds exist but chasing non-existent poor grounds is a waste of time (obviously). Ground loops can be a source of interference but they are influenced by electrical noise on the system so if the base system contains electrical noise, getting rid of loops is still leaving the underlying problem.
All unregulated power DC power supplies put out noise and wavy DC output. Yes, even though the alternator has a regulator, the actual output voltage is not really regulated. The only thing it is really regulating is the field current. . Look at the positive and negative DC rails on a high quality, high power, power amp with a scope, and you would be amazed at how much ripple and noise is in the DC line. And that noise is being generated by the power supply, not the alternator.

Grounds are where noise is sent to die. Grounds are a design engineer's best friend. In the filter being discussed here, how do you think the noise is being eliminated? It is done mostly by sending the noise to ground through the capacitors. It is actually easier to achieve noise filtering inside the product than it is to try to eliminate it at the source. A very large percentage of the components used in the electronics devices in our vehicles are devoted to eliminating noise.

Engineers do a really good job today of dealing with the noise generated by the alternator. But no matter how hard they try, they can't eliminate noise if the grounds they are using to eliminate it are compromised. If you fix the bad grounds, the noise filtering designed by the engineer will work properly.

It has to be said that like many things, the electronics in motorcycles are 15-20 years behind automotive technology with regards to handling noise. It is something they have not had to deal with. There are only a handful of motorcycles that have audio systems, and things like EFI, ABS, and BCM's are fairly recent additions. The motorcycle industry engineers are learning the hard knocks of dealing with noise today just like their automotive counterparts had to learn in the 80's and 90's.

That being said, the GL1800 was designed pretty well from the standpoint of noise, except for just a couple of glaring missteps in the chassis itself. The integrity of the chassis grounds is poor. Once those problems are fixed, noise is no longer a problem, and filters are mostly unnecessary.

Unfortunately, no matter how well the system is designed, many times owners and installers gum up the works by installing aftermarket electronics devices that re-introduce noise into the system because they don't know how critical the positioning of add on grounds and wiring is. Devices get installed without giving it a second thought. If it powers up, it must be installed correctly, right? This is how filters become popular. They are mostly a crutch to cover up poor installations, and the inability to troubleshoot the underlying problem.

If it works for you, go for it. Sometimes a minor noise problem just isn't worth what it takes to fix it if the root cause is well hidden. But we do know most of the causes of noise on this bike, and I think it is worth it to explore those solutions first.
 

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Discussion Starter #14
Well, to bring this thread back to ground - pun intended - because it's drifted right away from it's original intention and turned into a general discussion about noise sources, bike and otherwise.

The purpose of the thread was to point out a source of electrical noise in the Goldwing power train which is of a frequency in the audible range and which can be dealt with at source by a reasonably intelligent person using easily available components. It was not, and never intended to be, a treatise about all potential electrical noise problems on the Goldwing. And, like any postings I make on this site, it is based on personal experience and not a work of fiction as often seems to be the case.

However, I would like to make a few observations about points which have been raised. Please note, these points are not intended to be aimed at or critical of anyone, they are simply an extension of this thread for those who may be interested.

Firstly, the 'ground' on our motorbikes is not a true ground and, although we all use it, the word is misleading. A true ground, as used in our land based electrical supply is actually connected to ground - the earth's surface - and by dint of the earth's huge mass it behaves somewhat differently to our little motorbike frame which is largely a convenient way of making a negative battery connection for the bike's electrical components.Therefore, using a comparison based on characteristics of a domestic supply and equipment is not necessarily valid.
Secondly, the bike's electrical system is primarily DC (direct current) and direct current cannot make an audio input or output. Consequently, any interference we can hear in our audio system has to be AC or pulsing DC and have a source which is created by some other component or components. Most of our bike's electronic devices are capable of this and I'm sure much effort has gone into preventing audio interference, and successfully too, except not the alternator.

Ground loops: a second DC ground path for a component on the bike is not likely to be a problem but Larry hit the nail on the head when he mentioned the fitment of aftermarket electronics equipment to the bike without regard to its wiring or its original intended use. This is particularly the case where a piece of audio equipment has its own power supply in the form of a battery but can also be powered directly from its charge port. Ipods, MP3 players etc. are in this category and the problem arises because they use their battery negative as the negative output to their earpieces. When the earpiece connector is connected to the bikes audio system as an input, this makes their battery negative connect directly to the audio input of the bike, and, consequently, to the bike's ground. Now, when these devices are powered by their own battery they work fine but when connected to the bike power system an inadvertent connection is then made between the output from the earpiece back to the device's battery via a tortuous path through the bike's components and frame so a ground loop is made and this is likely to produce audio noise which can be heard from the bike's audio system. The solution for this type of interference is not filtering or playing with ground connections, it lies in breaking the loop. This is done by breaking the physical connection between the devices earpiece output and the bike's audio system input. At first this might seem impossible since there needs to be a connection between the two devices, but it's not impossible because the output is alternating current (AC) and there is a very simple device which will transfer alternating current without a physical connection and this device is a transformer. Simply put, this is essentially a couple of insulated windings around an iron core and what goes into one winding will come out of the other winding, hence we have a physical break in our loop but still have an electrical connection.

To sum up: 1) Filtering out any electrical noise at source seems to me to be the sensible way to go, after all, if it's not there for the rest of the system, it's not there! Also, it needs to be filtered out close to the component creating it because these types of electrical noise can also be transmitted from the cables carrying the noise (the cable acting as a transmitting antenna) and therefore are a risk to other devices capable of collecting airborne transmission.
As an aside, for this reason it's worth keeping power cables separated from audio cables and audio input/output cables would best be screened by using a shielded cable.

2) If an device needs to be used where a ground loop creates noise, playing with filters and relocating ground cables is likely to be ineffective at preventing the noise - the loop needs to be broken and a simple input isolator is the solution in this case.

3) In the case where there is a poor ground connection, perhaps a slack or corroded connection, this simply needs to be rectified and is a service fault rather than a basic electrical noise issue.
 

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J.W., my posts were also not intended to be critical, but merely to debate the topic, just like any group of engineers would do when designing a product when there is disagreement as to what is the best approach to solving a problem. In a complex system, those disagreements will happen hundreds of times during the design phase.

I only wanted to point out a different angle that should be at least considered by everyone reading this before jumping head first into a project. Everyone on this board knows that I am famous for playing devil's advocate.
 

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Larry, you always have a way of moving the topic way beyond my pay grade. :lol: :thumbup:
 

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Larry, you always have a way of moving the topic way beyond my pay grade. :lol: :thumbup:
Then you will be relieved to know that I did my best to hold back. :lol:

I do my best to phrase things in layman's terms here. Knowing your audience is the key when discussing anything technical. But I do still fail at it occasionally. It's tough when you are trying to keep it as short as possible. Even though it appears to be very simple concept to someone that does not have extensive background in electronics, the subject of grounds is in reality quite complex.

To put my posts in another light, look at it this way. I solve problems in electronics the same way I fix anything else. I don't look for the easy way out. I look for the correct way. I believe in eliminating the problem instead of just getting rid of the symptom. Use the wobble problem as an example. Replacing the stem bearings with roller bearings doesn't solve the problem. It just masks the symptom. I look at add on filters as being the same type of solution.

Sometimes masking the symptom is indeed the more practical solution, but it isn't where I start when troubleshooting.
 

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One suggestion to this discussion, is cleaning the G1 ground and providing a very good jumper from it to the G2 ground point will help everything that needs a good ground connection. The only mistake that Honda made was using the frame and engine as the ground path for all the secondary systems on the bike. Their use of the bare aluminum frame point and the fact it is a dissimilar metal from the wire lugs used on the wire ends causes an automatic resistance to appear at the G1 junction along with corrosion from humidity. Installing a good quality jumper from this point to the G2 point connects all those small system grounds back to the larger battery negative post, eliminating a possible resistive loop through the frame and engine.
 

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So where do I find a "how to" with pictures and parts to eliminate the annoying whining noise coming from my iPhone connected with usb power supply from bike and audio connected to earbud jack?
 
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