FJR Audio - Reducing Hum

[diablo456]

I've had my 2008 AE for almost 2 months now, just loving the bike. Thanks to everyone here for all the advice, help, etc. With your tutorials, pictures, and archives, I've confidently done many upgrades to my new bike, including handlebar risers, installation of an AudioVox CC100 cruise control, and fitting of a complete audio system.

I've learned a few tricks installing the J&M CB2003 that I'd thought I'd pass along. I've interfaced this with a Zumo 665 for GPS voice prompts, XM Radio, and MP3 playback. The combination of JMCB2003 and Zumo665 is pretty close to my ideal for MC audio. Anyway, my one issue was slight hum in the system. I used the J&M audio isolators, and they helped, but I still got a bit of ignition hum in the system. I've since found a very simple fix for this, given below.

I have a set of J&M elite headsets from my 10 year old GL1800. To use these with the J&M CB2003, I needed to acquire new 6-pin lower cords to interface these helmets. I ordered 2 cords, one straight through, one with volume control.

The output level of the J&M is very high, and the Zumo out is passed through as ear-splitting volumes if you want. Well, this gives a great option to control noise using the volume cord. I dial back the volume control on the cord, which greatly reduces - more like eliminates - the background ignition hum. Then, I just dial back in the XM/MP3 volume using the aux volume control on the J&M CB2003 and up the intercom with the dedicated intercom volume knob. Works like a charm! Now, good music, plenty of volume control, and no noise/hum. As a bonus, my fiancé can adjust her own volume to her taste with this method as well. After finding this huge benefit, I returned the non-volume cord for a second with volume control.

Good news: works like a charm

Bad news: J&M hardware, headsets, and cords are ridiculously overpriced.

Just thought I'd document this here for anyone else looking to eliminate hum.

Joe M.

 

[Pale Rider 07]

Hey Joe, thanks for the post. This solution interests me. I'll have to dig into it a bit further. One thing I did notice, on a non-related issue. Your risers look like they might not be seated all the way. I had the same ones at one time and had to sand a bit of the finish off the alignment pins. Once I did that, they seated nice and flush with the clamp. It's not a big issue, just thought i would mention it. Btw...your comms setup looks great, like it was factory installed.

 

[diablo456]

Dave, good eye! Really glad to have the comment. I mounted them in the lowest of the 3 pins, and they overhang just a bit with the rounded lip on the triple clamp. I did check twice for a firm fit on the risers, but I'll recheck. No problems, they've been solid for a month since the install, but safety first, always.

 

[DJB]

Joe, I have had the JM2003 since like 2004 or 5 on my FJR. I have integrated it with 2 different Garmin units over the years along with a IPOD under the seat and now a ZUMO 550 with Satellite radio. I do have some questions for you as I alway have had some issues. What did you do with all the extra wire, how did you ground and power the system. Where did you mount the satellite radio antenna. Have you also integrated bluetooth and a GMRS radio yet. PM me so we can converse without bothering all the rest of the world if you like.

 

[diablo456]

Happy to help. Mind as well post here in case others are looking to cut down hum. I ran the primary harness in the area under the glovebox. Harness cables for the headsets come through the left front, down the left side of the engine bay (removed gas tank for install) and under the seat. Not a lot of extra room, but the cables fit. All power lines for everything in the system where run through the power isolation box supplied by J&M and this was wired to the cigarette lighter in the glovebox. Hookup for both ground and hot from the power isolation transformer go to the ground and hot from the lighter. Output from the isolation transfer is wired in parallel to the harness for both the J&M CB2003 and the Zumo 665 harness.

The XM antenna is mounted on the back deck, see pic below. Zumo harness is routed into the left side of the engine bay, zip-tied to the J&M Harness, and continues under the seat. There's maybe 6" of free cable for the mini-USB connection to attach the XM antenna at the back to the Zumo harness in the front. It's tight, but not crazy-tight.

I also wired an audio isolation transformer (from Radio Shack, also known as a ground loop isolator) between the Zumo audio out and the J&M CB2003 audio in. Finally, I use volume control cords as described above. With this setup, I have plenty of audio volume (too much, actually, it will clip at high levels) and no ignition hum.