Baehr and Hum/Buzz Solution

[Daza]

Attached is a method of stopping the hum/buzz that some people experience with the Baehr K1200LT Intercom and systems (two way radios, music players, GPS systems etc.) that have been added to the bike and powered from the bike.

This will not stop any problems with systems plugged into the Intercom but self powered by batteries, for example, an Ipod, it will only help if the system is drawing its power from the bike.

This does not fix all hum/buzz problems, but it will fix the problem if it is caused by an earth loop.

Daz

[CARNEYM]

I have the K1200LT system and I am currently trying to get the cable ESF-05-02 from Baehr Germany (they say this will fix the ground loop problem), with not much luck so far. I have a terrible ground loop problem with my CB radio and no matter what I do, I cannot get rid of it. Will this fix that problem. By doing this will it create any other problems. I hope this will work. How did you insulate the wires (with tape). Thank you for any help you can give me.

Mickey Carney

[pozo_izquierdo]

Mickey,

I´m afraid that the part number you referred to, will not fix your problem. At least it was worthless for me. I have been fighting with the same problem and you can read the whole story here:

http://www.bmwlt.net/ubbthreads/showthreaded.php?Cat=&Board=K1200LT&Number=290837&page=&view=&sb=&o=

Tomorrow I will try the recipe Daza offered and will see if it works for me. I'll keep you guys informed.

regards

[CARNEYM]

Make sure that you notice the is a new cable ESF-05-02 not the ESF-04-01 like in the post you referred to. I wrote Baehr myself and this is the reply I got back.

Dear Mr. Carney,

thank you for contacting baehr-Company.

You can't use the ESF-04-01 cause it's too weak for a CB-Unit. The ESF-05-02 will solve this problems.

[pozo_izquierdo]

You (and Baehr) are right Mickey. As my problem is between two Baehr units the ESF-04-01 can handle the Capo II power demand.
The previous unsuccesful gadget we tested with my Baehr dealer was AEF-02-02 and I got that mixed up with the unit you suggested.
Sorry for the confusion. If the simple ground loop fixing by "Daza" will not cure the buzz problem, I´m sure the ESF-05-02 will. I think it uses the same DC-to-AC-and-back-to-DC-technology as the ESF-04-01 but is just built for heavier amp rating.

Regards

[Daza]

Hi Mickey,

This should solve the problem for you. It did for me and the 2 other bikes I have done it on that had CB radio problems. I will update the drawing over the weekend to emphasize the most important thing about this mod, that is, the new wire that you add from the brown wires on the black box must go to exactly the same earth point as the earth (-ve) of the CB radios power connection.
As for the method, it is best to solder the wires if you can and insulate the changes to ensure that they cannot touch a ground/earth point. (or anything else for that matter) I use heat shrink tubing to insulate with, but tape will do the trick.

[pozo_izquierdo]

Hi Daz and Mickey (and others)

This morning I went and took off the trunk of the bike in order to have access to the wires Daz referred in his instructions. Before doing that I started the bike (It has been sitting "winterized" 3 weeks now) and checked the buzz in my molded earplug speakers both with the Baehr ESF-04-01 filter hooked in and without it. This was just to recollect the level of humm/buzz with and without the filter.

I cut the brown wires as instructed, soldered them and used the shrink tube for insulaton. I ran the new earth wire directly to the battery negative as that was the point that my Baehr Capo II (bike-to-bike radio) was grounded, too.
I connected all the bike and Baehr connectors, left the Baehr ESF-04-01 filter out and started the bike.

The result: The buzz was still there but I have the feeling that it had diminished some. I put the ESF..filter back and the buzz was gone totally.
Then I left my earplug speakers out, put the helmet in my head and listened the buzz through the helmet speakers. As the bike still has the Remus Sport can on the buzz was pretty much covered by the bike exhaust sound. When I raised the radio volume in order to hear the radio over the bike sound the buzz was not really all that disturbing any more.

Conclusions: In my case the only way to totally eliminate the alternator buzz from coming through the Baehr Intercom equipped with a Baehr bike-to-bike radio seems to be the Baehr ESF-04-01 (or ESF-05-02 for non-Baehr CBs etc) filter. I have to remind you that I'm wearing custom molded earplug speakers which bring all the sound (and buzz for that matter) directly in the ear channel. The recipe Daz provided is definetly worth trying as it might be of enough help in many cases. Of course every CB, bike-to-bike radio,etc. is different and they all have their characteristics.
It can also be that I have been spoiled by the Baehr filter cutting the buzz totally and I no longer can settle with any extra noise in my ears...

Regards

[Daza]

Hi Ari,

Good that you tried it. I guess I should explain what this change does....

The Baehr K1200 Intercom picks its 12 volt power from the bike by way of the two connectors, as well as picking up the left and right channels of the bikes sound system.

By cutting the brown wires as shown, you are returning the cabling between the two connectors to the way it originally was, and supplying -ve (earth) to the Baehr by adding the new wire and connecting it to to the same point as your CB etc.

This should eliminate all chance of ground loop as long as the other device is not connected to earth at another point.

In the case of a CB, other connections to earth can occur, e.g. by way of mounting the unit as the metal case of the CB is usually also at -ve (earth) potential.

Another possible earth loop problem area is a CB whip antenna fixed to the bike. This can create a earth path back to the CB by way of the shield in the coax cable.

This mod will not help if the noise in your system is induced because the wiring is run too close to ignition cabling etc. On that subject, if you mount your system in the recommended location on top of the battery, don't forget that the alternator is just in front of the battery so don't stuff cables that are too long under the tank to hide them as there is a good chance they will be sitting on top of the alternator and picking up lots of noise....

Anyway, enough of my rambling....trust this helps explain what the changes do.

[Daza]

Hi Mickey,

Sent you a PM today re the ground loop problem.


Daz

[CARNEYM]

I thank you both for all the info. Pozo, I am wondering how the Baehr filter cable, connects to the unit.

Mickey

[pozo_izquierdo]

Hi Mickey,

here are two pictures of the Baehr ESF-04-01 filter. The unit on top of the battery is the Baehr Capo II bike to bike radio.

The ESF-05-02 filter you are getting is likely to look like this but it might be slightly larger due to its higher amp capacity.

I hope it solves your problem.

Regards