Headlamp Modulator Feedback


Technical information and Q&A applicable to all years and models of Goldwings
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WingT
Posts: 8
Joined: Tue Jun 19, 2012 8:38 pm
Location: Oshkosh, Wisconsin
Motorcycle: 1997 gl1500 Asp SE

Headlamp Modulator Feedback

Postby WingT » Sun Jan 19, 2014 10:28 pm



Hi- I have a beautiful, '97 SE and after reading about guys using headlamp modulators, I installed one.
Following the excellent instructions in the how to forum. All went well.
I love it, and have noticed on several occasions, the modulator kept people from pulling out or turning in front of me.
But when I am listening to my stereo especially through the headphones, I am getting a wow,wow,wow noise that is very annoying.
Has anyone had this happen? or have any suggestions?



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WingAdmin
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Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: Headlamp Modulator Feedback

Postby WingAdmin » Mon Jan 20, 2014 10:37 am

The headlight modulator is causing a fairly large amount of current (close to 100 watts) to switch on and off rapidly. This can affect the audio, which is very sensitive to voltage noise and changes. You can mitigate it in several ways:

- Larger capacity battery and/or alternator
- Choke filter and/or filter capacitors installed on the headlight wiring in fairly close proximity to the headlight

I already had an AGM battery and Compufire alternator, so I went the choke route. I built my own choke using some magnet wire and a toroid, and also used some fairly large electrolytic capacitors to help buffer the switching. This made a fairly big difference.

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redial
Posts: 1993
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Location: Kapunda, SouthAustralia
Motorcycle: 1997 GL1500 Spectre Red Aspencade

Re: Headlamp Modulator Feedback

Postby redial » Tue Jan 21, 2014 7:15 pm

WingAdmin,
Do you have a set of materials and pictures (we love pictures :D ) of the item? It sounds like just the trick to cut the wow, wow, wow from the earphones, and move the wows to the spectators.
Len in Kapunda

The world is not going to finish today, as it is already tomorrow in Australia and New Zealand, and other islands of foreign nations such as Guam and Samoa.

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WingAdmin
Site Admin
Posts: 17050
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: Headlamp Modulator Feedback

Postby WingAdmin » Tue Jan 21, 2014 9:36 pm

redial wrote:WingAdmin,
Do you have a set of materials and pictures (we love pictures :D ) of the item? It sounds like just the trick to cut the wow, wow, wow from the earphones, and move the wows to the spectators.


I used a coupled inductor circuit on the toroid, looks like this:



"A" would be the 12v/Ground powering the light, and "B" would be where the light is connected.

The ferrite material of the toroid core is shared between the "out' and 'return" paths. If you look carefully at the sense of the windings, the fluxes generated by the load current passing are in opposite senses, so roughly cancel (differential mode). When there is constant current (DC) flowing, the toroid is not in saturation, so it doesn't touch anything. When the circuit is ramping up or down, the opposite flux of each winding cancel each other damping the sudden ramp up/down. A big electrolytic helps temper that sudden ramp up/down as well.

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redial
Posts: 1993
Joined: Mon Jan 03, 2011 1:17 am
Location: Kapunda, SouthAustralia
Motorcycle: 1997 GL1500 Spectre Red Aspencade

Re: Headlamp Modulator Feedback

Postby redial » Tue Jan 21, 2014 9:49 pm

Thank you. I trust the cold weather is not keeping you from your real work?
Len in Kapunda

The world is not going to finish today, as it is already tomorrow in Australia and New Zealand, and other islands of foreign nations such as Guam and Samoa.

User avatar
WingAdmin
Site Admin
Posts: 17050
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: Headlamp Modulator Feedback

Postby WingAdmin » Wed Jan 22, 2014 11:26 am

redial wrote:Thank you. I trust the cold weather is not keeping you from your real work?


My bike has been in pieces in the middle of the garage for a few weeks now. :)




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