SL/R230: Playing audio from iPhone to speakers
Thread Starter
Junior Member
Joined: Jul 2010
Posts: 59
Likes: 1
From: Lecanto Florida
SL500
Playing audio from iPhone to speakers
My 2003 SL500 has an aux input in the glove compartment. I want tp play podcasts and audio books from my iPhone through the car’s speakers. I have a Belkin connection from the cigarette lighter to a splitter. From the splitter one wire goes to the aux input and the other goes to the iPhone where it both charges the iPhone and carries the audio signal back to the splitter and on to the aux input. This works so that I can play audio through the car’s speakers and charge the phone at the same time. The problem is that I get electrical interference (a whining sound that increases in pitch as the engine speed increases). Is there a way to get rid of this noise? I tried a Bluetooth dongle in the glove compartment, but it didn’t work well and I would have to take it out often to recharge it. I inquired about putting in a new head unit that would even include Apple CarPlay, but apparently the fiber optic connections in this car make that very difficult. I just want good clean audio from the phone while keeping it charged. Any ideas?
Last edited by twilightround; Aug 28, 2018 at 02:58 PM. Reason: typo
Banned
Joined: Jan 2006
Posts: 1,982
Likes: 393
From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
I simply have one cord from the cigarette lighter attached to my phone for its power, and a separate cord from my phone headphone output going to the AUX jack. It works perfectly well.
MBworld Guru
Joined: Dec 2009
Posts: 10,782
Likes: 1,011
NO LONGER ACTIVE
My guess is that the OP has a newer iPhone that does not have an headphone/audio output jack. On those, you have to plug an adapter into the Lightning port that provides the headphone jack. Belkin makes this device to allow for simultaneous listening and charging: http://a.co/d/7y3t6oY Apparently, that introduces too much electrical noise into the system.
Thread Starter
Junior Member
Joined: Jul 2010
Posts: 59
Likes: 1
From: Lecanto Florida
SL500
Thank you for the responses. Rudeney is correct. Apple tells me they did it that way to make it waterproof ... If I understand fxformat’s solution, it still leaves the question of how to charge the phone while listening without getting the electrical interference through the cigarette lighter.
Member
Joined: Nov 2009
Posts: 151
Likes: 6
From: Central Mass
2003 SL500, 2016 F250, 2017 Jeep Renegade
I have same one, well similar, Chinese. But have it set to broadcast on lowest FM 87.7 so no inference and with USB Charges Phone. Mine also has a Micro SD Slot in it to play Music from and it has a Microphone for hands free calling. I've had it about 2 yrs now. I wish the Neck was a little longer as the Tiny Control Head sits level with swifter. But connect VIA Bluetooth just fine.
Junior Member
Joined: Aug 2016
Posts: 18
Likes: 6
From: Bremerton, WA
2005 SL500 Designo Edition
From my former car stereo installation days and from what you are describing, I think it could be what is referred to as a ground loop. They make these ground loop isolators,
which are supposed to eliminate what you are describing. I have also seen certain USB/BT units (like what cadbob shows above), create a lot of EMI which presents itself as interference on radio stations when you are listening to OTA broadcasts. It took me three tries before I found that worked correctly and just like above, it was the least expensive Chinese knock off that worked the best. Here is the one that I used.
Last edited by wmmorrell; Aug 29, 2018 at 04:38 PM. Reason: Additional info
Trending Topics
Thread Starter
Junior Member
Joined: Jul 2010
Posts: 59
Likes: 1
From: Lecanto Florida
SL500
Thank you, wmmorrell. I might try the ground loop isolator, though I would need a different connector than shown on the amazon link, for my current setup - a male 3.5 on each end. Also, if it were not in the glove compartment, it would be more clutter, which I'm trying to avoid. I think I have enough volume so that the loss would not be a problem. As for the ones using bluetooth from the phone and an FM frequency, I have two questions. First if I also recharged the phone from the USB port on the device, might I get the same ground loop problem? And how good would the FM sound be? I live in a family urban area with lots of FM stations. When I try to find a frequency that is unused, I get quite a bit of noise. Would that static still be there when using the device?
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Junior Member
Joined: Aug 2016
Posts: 18
Likes: 6
From: Bremerton, WA
2005 SL500 Designo Edition
twilightround, You are very welcome. The "Ground Loop" isolators come in a variety of flavors, they may make one that has the male 3.5's on each side. MB elected to delete the AUX INPUT jack �� in 2005, so I never really looked. A small adapter could be used to go from the female to male, however I understand about the clutter thing. Not a big fan of it myself.
As for your second question, I live in the Seattle area and though the unit is not 100% perfect, I have no complaints. I get great reception using the 88.1 frequency, (I also saw somewhere that there is a way to drop it to the 87.8, I think. I have not confirmed that though). I can charge my phone or any USB chargeable device with no interference or noise, answer and place phone calls with the unit (this surprised me at how well it worked, especially since it sits in the lighter socket, I had the top down and just rolled up the windows). I can adjust the volume, skip forward and back and a few other things. It even fits nicely in the lighter socket and does not interfere with the shifter. The only drawback, if you want to call it one, it is a little tight when you try to plug in a cable into the charging port with the shifter in park. :-) Hope this helps.
As for your second question, I live in the Seattle area and though the unit is not 100% perfect, I have no complaints. I get great reception using the 88.1 frequency, (I also saw somewhere that there is a way to drop it to the 87.8, I think. I have not confirmed that though). I can charge my phone or any USB chargeable device with no interference or noise, answer and place phone calls with the unit (this surprised me at how well it worked, especially since it sits in the lighter socket, I had the top down and just rolled up the windows). I can adjust the volume, skip forward and back and a few other things. It even fits nicely in the lighter socket and does not interfere with the shifter. The only drawback, if you want to call it one, it is a little tight when you try to plug in a cable into the charging port with the shifter in park. :-) Hope this helps.
Last edited by wmmorrell; Aug 29, 2018 at 06:56 PM. Reason: edits
Newbie
Joined: Jun 2015
Posts: 6
Likes: 1
2005 SL500 Base
Aux audio connection in SL
Dissapointed that MB “deleted” the Aux audio input starting with the 2005 production year. Guess what year SL I have. Would like to understand if the input to the audio system still exists and if I could simply add a connection to it. One suggestion I might make for those of you that are experiencing an audio whine that increases in pitch as you increase the engine speed. I believe that the alternator is part of the problem. The twelve volt system is electronically noisy, as far as any other connected device is concerned. While I obiously haven’t been able to reproduce the problem, I have used a ferrite bead, or “choke” to suppress the whine. If you look at some of your computer power supplies or other peripheral devices, you may see a tublar component surrounding the power or signal cable. That’s the ferrite choke, and are typically used to suppress RF noise and/or electrical interference. They are easily obtainable at a decent electronics store, Amazon or the online version of Radio Shack. Pass the cable through the center of the choke and loop it around and through once more before snapping the two halves of the choke together. Hope this helps.
