I need to pick the brain of people with electronic background.

I am buying a marine stereo to install on the bike (4 x 40w).

The fairing is equipped with the original BMW speakers
The chair has 2 speakers and my helmet has also a set of speakers.

The 2 front channels will be used for the bike and the 2 back channels for the sidecar.

I want to be able to switch off the back channels when nobody's in the chair.
Is the negative output common to the 4 speakers?
If yes, can I connect the 2 negative (-) leads together and just install a switch to shut off the speakers?
If I shut off the negative, Do I take a chance of burning the output transistors on the back channels?

I don't know if turning the fader full to the front will shut off the rear speakers.

I want to install a jack on the front output in order to plug the helmet speaker and not blast high volume music when riding in quiet neighborhood.
I know that I need to install resistors, but don't have any idea of the value.
Anybody knows off hand what value I should use?



Thanks in advance.

CF

As your not going for audio fidelity it should work using a common - on both of the speakers for the side car and having a switch that kills just the + side will work to stop any audio coming out of the sidecar.

I've not known it to be a problem not using the rear channels on a stereo or using them on an intermittent basis, modern circuitry would deal with it all....

For the helmet one option is to use a socket that is a make/break so when your not plugged in the audio routes to the speakers on the bike and when you do plug in the audio is routed to your helmet. I am guessing that you would be looking at impedance matching the radio o/p to the helmet speakers impedance. That or a aux volume control knob (variable resistor) which allows you to change the volume when riding without touching the radio.

go carefully there bert

most all the modern car stereos are "bridged outputs " that is ...an amp pushes on the positive side and there is an amp on the negative side (180 DEGREES OUT OF PHASE) that pulls .

it has become common practice industry wide since at least 10-15 years ago. the tell tale is the wattage ratings ...anything over 10 watts (real ) is bridged output device .(and often rated into 2 ohms load ).

just a heads up ....keep the negatives separate and treat each one as live .

an easy way of making a single ended output for head phones is to use 1 x 22ohm resistor (5watt type) across the output, tap the more positive wire and ground and feed to the head phones (obviously 2 required for stereo ) this can be switched as suggested ...but carefull as you go .

the resistors in line with the head phones ....used to be somewhere in the order of 330 ohms ...on most domestic hifi stereo systems ...it was more a current limit than anything else ...so a little leeway might be ok ...so probably anywhere between 100 ohms up ? experimentation will be your best guide .

the selection of headphones is quite important , you will be looking for really good output figures as in db output per watt ...yeah i know they ar'nt rated that way but ..you will find that senheiser are great for at home but not able to produce the reguired output volumes that you will need to overcome wind noise comfortably and without going into distortion ....i have worked with these types of things before ...and i can advise ...look for a mylar type driver (speaker sound element ) and what sounds exteeemy loud in comparison to others ....some old earphone elemets out of telephones work exteeemly well in this case ...again experimentation to what suits is required .

the faders front to rear ...used to be passive devices ..so worked on current limit principals ...and would not turnoff completly the sound to the speakers ....these days the fader is electronic and adjusts the input to the amplifier rather than the output ...so you may be able to get quite a good reduction in volume to the speakers by using the fader ...but expect some bleed of sound in any case .

you may not find much technical help from most sales folks, but persist ..there will be someone that will know the "ins and outs" properly ...good luck !

hope that helps

Bert, I appreciate you're looking for a simple solution, but I would invest in a communication set like the Starcom1 Advance or similar.
You'll be able to connect all kinds of equipment, have it properly switched, allows you to talk to your passenger during the trip and if both have speakers in the helmets why would you need them on the bike?
Alternatively the amp will normally see a load of around 8 Ohms. Switching other speakers in parallel would lower that load and potentially overload the amp. Putting them in series might work, but will sound a lot lower in volume. Then you would need a double switch per lead (pos and neg, see above) to disconnect the speaker and switch a resistor into the circuit so the amp sees the same load (otherwise the volume would suddenly go up substantially). The worst sound-wise, but possibly the simplest is looking at an car audio fader that allows you to adjust the volume between two sets of speakers? Talk to a car audio sales person. CT should be able to advise ;-)
BTW putting resistors in series as above will seriously lower the volume in those speakers, but do little else. Overly simplistic, but speakers are about 8 Ohms, whilst headphones can be anything between 50 and 600 Ohm.

I received my marine radio and I am quite impressed with it.
I bought it on Ebay after reading good reviews on a Goldwing forum.
The radio is not waterproof, but water resistant (read between the lines)...
Today I decided to work on making a support to fit it into the left glove box.
I had a small accident (or incident). The box fell from the workbench.
The lip covering the fairing broke .
I already checked on the Internet and I can find one for cheap. I will first check with RJtrucker as forum members come first.

This incident didn't stop me to continue making the support.
The radio is only 4 1/4" deep and it makes it easy to fit on a bike.
As it is under warranty, I tried to plug my helmet speakers and.... it works without even having to install a resistor.
Here is how I cut the 1/8" aluminum plate. I am planning to install the jack for the helmet speakers on the plate + a couple of switches like the one to transfer the fuel from the auxiliary tank in the sidecar trunk to the bike tank.





For people interested, here is a link on the radio specs.

Since this thread is about changing out the genuine radio/casette player on the bike.

The german company AKE electronics makes A/D converter, which makes it possible to use the genuine remote control on the bike together with Blaupunkt or Sony autoradios (different converters).

But a bit expensive,...but if you like to keep the bike as genuine as possible,
it's a nice solution.

Got this converter, together with a Blaupunkt with SD card reader.........
but not on the bike yet.

Crazy Frog wrote:I received my marine radio and I am quite impressed with it.
I bought it on Ebay after reading good reviews on a Goldwing forum.
The radio is not waterproof, but water resistant (read between the lines)...

For people interested, here is a link on the radio specs.

Seems a competitive price CF,,,,thanks for the link.
88

Just do what a friend used to do. He had a 52ft yacht and sailed all round Oz and has now gone world cruising but he bought a cheap car radio from Kmart (readWalmart) and every time he was in a port with a Kmart he would take it back and say it stopped working and get a refund, then go and buy another one and get 12 months warranty on the new one. He always had a good cheap radio that would never get time to corode and stop working in the marine enviroment.
It cost $29 as against $499 for a "proper marine radio" which probably wasn't any better just more expensive to cover warranty claims.

its extreeemly easy to open it up and coformal coat all the electronic boards internal .

just the really hard things are volume controls etc ...so i likes all the digital pushbuttons these days ...makes it so easy