Headset noise

[crock4]

I recently installed a headlight modulator on my bike, and I can hear it modulating through the headset when in the intercom mode. It's not real loud, and when the audio is on you don't notice it. Is this normal or did I do something wrong installing it. Has anyone else had this issue? I did find out that getting to the high beam light on the left side was a vocabulary enriching experience I don't want to do again.

Bob

[flogger]

I have a 1500 and use the newest J&M headsets top series... no modulator though... I can hear my turn signals very faintly with no music or at low RPM while stopped (no wind noise). I don't have an answer and don't know how related this may be... I would suspect they are and that it's like cars I've seen over the years transmitting engine noise/hum over stereo speakers? Electricians?

[crock4]

I also have a JM headset. I don't have any other noises from turn signals, switches etc. Only the headlight modulator. When I turn it off the noise stops. It's not really loud enough that it is an issue. I was just curious if anybody knew what makes it happen. I've gotten to like riding with no radio, especialy when my wife is with me. It's even more annoying to have the music keep muting everytime someone says something. Thanks for the reply Mr. Flogger.

Bob

[Wayne]

It is very common for the modulators to be heard in the headsets and especially since the newer headset speakers are very efficient they will pick up this switching of the diodes. This is the reason that Sierra has never offered, other than a brake light modulator by J&M in the mid to late 90's, a brake or headlight modulator because then we would have be expected to get rid of the pulsing which is really difficult to do.

[crock4]

It is very common for the modulators to be heard in the headsets and especially since the newer headset speakers are very efficient they will pick up this switching of the diodes. This is the reason that Sierra has never offered, other than a brake light modulator by J&M in the mid to late 90's, a brake or headlight modulator because then we would have be expected to get rid of the pulsing which is really difficult to do.

Thanks for the info. This is a great forum..

Bob

[WingAdmin]

It is very common for the modulators to be heard in the headsets and especially since the newer headset speakers are very efficient they will pick up this switching of the diodes. This is the reason that Sierra has never offered, other than a brake light modulator by J&M in the mid to late 90's, a brake or headlight modulator because then we would have be expected to get rid of the pulsing which is really difficult to do.

Unfortunately, when you turn a light (drawing a lot of power, compared to the overall power available on the bike) on and off quickly, you're going to be creating big pulses that the very sensitive audio system is going to pick up.

There are a number of ways of reducing (if not eliminating) the noise.

The first way is to reduce the power being drawn and switched - going to LED headlights can help with this as they draw much less power, although you will then need an LED-specific modulator.

On my GL1500, I did a lot of work to get rid of the noise. I installed a custom dual choke that I designed, along with some huge electrolytic capacitors, all very close to the headlights. The chokes smooth out the transitions from on/off/on, and the electrolytics store power so that the sudden surge is sucked from them instead of from the bike. With these I was able to almost completely eliminate the noise from the audio system - but it took a lot of work and experimentation to get there.

[crock4]

It is very common for the modulators to be heard in the headsets and especially since the newer headset speakers are very efficient they will pick up this switching of the diodes. This is the reason that Sierra has never offered, other than a brake light modulator by J&M in the mid to late 90's, a brake or headlight modulator because then we would have be expected to get rid of the pulsing which is really difficult to do.

Unfortunately, when you turn a light (drawing a lot of power, compared to the overall power available on the bike) on and off quickly, you're going to be creating big pulses that the very sensitive audio system is going to pick up.

There are a number of ways of reducing (if not eliminating) the noise.

The first way is to reduce the power being drawn and switched - going to LED headlights can help with this as they draw much less power, although you will then need an LED-specific modulator.

On my GL1500, I did a lot of work to get rid of the noise. I installed a custom dual choke that I designed, along with some huge electrolytic capacitors, all very close to the headlights. The chokes smooth out the transitions from on/off/on, and the electrolytics store power so that the sudden surge is sucked from them instead of from the bike. With these I was able to almost completely eliminate the noise from the audio system - but it took a lot of work and experimentation to get there.

Thanks Mr WingAdmin for your explanation, and solution to this issue, and if I was half smart I would probably understand some of what you are talking about, BUT alas I am just happy people have stopped pulling out in front of me. You, and the other very knowledgable folks here are what makes this forum such an asset for the Goldwing community.
Bob

[WingAdmin]

I *just* put a set of LED headlights on my GL1500. I also installed a Kisan Pathfinder LED-specific modulator, and the amount of noise coming through the intercom AND radio made the audio system completely unusable. It was REALLY bad. The modulator uses pulse-width modulation to dim the LED, and this creates a "buzz-buzz-buzz" noise over the audio system - even over the speakers.

I spent some time last night building a noise filter consisting of a toroid choke and a series of electrolytic capacitors to kill various frequencies (and harmonics) of noise coming from the modulator. After installing it, the noise is completely gone.

My homebrew noise filter

[WingAdmin]

I should note that Kisan recognized the noise problem with their LED headlight modulator, and has modified the programming in it, to soften the transitions between "on" and "off" - which reduces the noise considerably.

I have the new version in my bike now, which was supplied as a replacement at no cost. Whereas with the old modulator, the audio system and intercom were completely unusable, this is no longer the case. I can still faintly hear the noise over the intercom, but not over the radio at all.

I left my noise killing circuit in place, and with it, there is zero noise anywhere. I think I'll leave it installed.

[Fiberthree]

I spent some time last night building a noise filter consisting of a toroid choke and a series of electrolytic capacitors to kill various frequencies (and harmonics) of noise coming from the modulator. After installing it, the noise is completely gone.

Would you mind posting the schematic? The PWM I installed for the brake/running lights is also putting a terrific buzz into my audio system. Thanks.

[WingAdmin]

This is the circuit I used for my headlight modulator. You can also download it here: Noise Suppressor Circuit

Noise Suppressor Circuit

The Blue/Black wire on the GL1500 is the high beam wire, and Green is ground.

First the +12V enters through a pair of 10 amp diodes - this is more than enough to handle the two LED headlights I'm running, which draw 2.3 amps each (OEM halogens draw about 5 amps each).

Next it enters an array of electrolytic capacitors. Starting with a pair of relatively large 2500uF capacitors, next a 500uF, then a 50uF. I used 25V rated capacitors, which is safe for the 13.8 volts encountered in the bike.

Next the power enters a standard 20 amp automotive relay on pin 87, exiting on pin 30. More on this relay in a minute.

Lastly, it goes through a toroid choke. I used a standard ferrite toroid, wound as shown in the hand-drawn diagram. Note the direction of the windings - this is important! The more windings you can cram onto the toroid the better, but they must be neat and lay flat against the toroid. I used a 1.5 inch toroid and got about 7-8 windings using 16 gauge wire.

From there it heads off to the headlight modulator. Pulses induced on the power bus by the modulator's PWM circuit are first attenuated by the toroid choke, and then any harmonics and pulses left are smoothed out by the electrolytics. It is important that all of this be as close as possible to the headlight modulator (or source of noise).

Lastly, the relay: The coil of the relay (on pins 85 and 86) is connected between the blue/black high beam BEFORE the diodes, and ground. The reason for this is that the large electrolytics can supply power to the LEDs for several seconds even after the power is turned off! If you want to flash your high beams, well, you can't, because you've got several seconds of power stored in the capacitors that keep them running AFTER you switch them off.

Therefore when the power is switched off to the high beam circuit, the relay coil is de-energized, disconnecting the headlight from the capacitors, and turning it off instantly. The two diodes are used to prevent the capacitors from backfeeding the relay coil.

BE CAREFUL when testing this circuit - after it is turned off, the relay prevents power from exiting the capacitors as do the diodes, so even though the power is turned off, there is still a significant amount of charge remaining in the capacitors that is not draining off anywhere - enough to give you a nasty zap should you be unfortunate enough to touch their leads.

I hope this is of some help!

[Fiberthree]

Thank you. I'll give this a shot... as soon as I can sneak out to my local electronics shop to get the parts. The wife got back from a six month visit to our daughter in England and now I there are a few more projects that are "more" important than a little buzz in my helmet. At least until we both hop on the Wing and she hears it.