When the SR10 is powered from the bike, and connected to audio devices that are also bike-powered, ground loops are formed between the devices and any electrical noise present on the bike's electrical system is heard through the SMH10. When connected to both a radar detector and a two-way radio, the noise is strong enough to trigger the audio from the SR10.
Removing the devices from bike power eliminates the ground loop and the noise goes away.
Bob, Ken ... You don't need the adaptor. The SR10 unit itself recognizes the difference between 12 volts and usb 5.1. I know because I cut off the adaptor and used the remaining cord to wire directly (though a keyed relay) to the battery. Unit is permanently mounted under a shelf and turns on and off perfectly with bike power. Oh, and no noise either. See my post back on June 5.
Chris - Sure, with the right skills, parts and knowledge you can certainly MacGyver something that works. Not sure your relay solution would work on a CanBus electrical system though. Most folks, including me, would just want a plug and play solution without farting around too much with it. If your not afraid to cut wires, mess with relays, isolation transformers, have good soldering skills and have the time then, by all means, go for it. After all,what could possibly go wrong! :) There is just too much magic going on with my bike's CanBus system for me to even think about messing with it beyond hooking accessories directly to the battery. If Sena is planning on an "Optional 12V bike-powered kit with on/off control by ignition switch" as mentioned on their overview and pointed out by Peter and it solves any ground loop problems then that may be a much cheaper and more elegant solution. Hopefully Peter will check into it and report back.
For Bob - I get what you say and are showing me but It's just a 12 V charger with a switch on it. If there is continuous power to the accessory plug as most are, then you can't just turn it off by the ignition switch which is what I think Peter is interested in.
Ken, I don't believe Sena is planning on anything other that what they have already delivered, the SC-A0103. Maybe at some point they'll make a version with bare leads instead of a cigarette lighter plug, but I doubt it, as anyone can make the same by simply cutting the end off a standard USB cable (although the SC-A0103 does have a few zener diodes inside to drop the voltage a bit from the 14V+ you get with a running vehicle down to around 12V). As Chris stated, the SR10 itself detects 12V coming in on the +5V USB line and turns itself on and off with the power (if you feed it 5V then it simply charges). I made my own adapter with a spare USB cable and a 7812 regulator.
Sena's bike power kit doesn't solve any ground-loop problems, it introduces them. Having a 12V power supply to the SR10 that is isolated from the bike would help, right up until you also plug in two audio devices powered from the bike and you get a ground loop between _them_ (Refplusten, glad you have a system that's working, now try adding a bike powered radar detector, or GPS...). The real solution would be audio isolation transformers mounted internally to the SR10 so that it would work as advertised. External commercially available audio isolators also help, but they don't work on the two-way radio audio as they would defeat the PTT function to the radio. This is why I'm building a custom audio isolator that will preserve the PTT function for the two-way and also provide isolation for the two aux inputs. I have the parts, I just haven't had the time. (And since I broke the motor on the bike at the track, now I need to rebuild that before worrying about the radio).
Peter - That was exactly my point to Adam back a few posts. We agree here. Sometimes it just takes some smart MacGyver types to find solutions. Too much work for me though! I just plug in my tank bag and go.
Often there is a disconnect between the marketing people and the engineering folks which is maybe why you saw the feature listed in the overview but no product accessory that matches the description.
Good luck with getting your bike back on the road. Ride on!
Big problem when I used the Sena supplied 3.5 mm cable to connect an Escort 9500ix radar detector into an SM10. Blew the audio out of the radar detector and needs repair. Escort says a mono isolator chord required to plug in a mono radar detector into a stereo device (SM10); to prevent excessive voltage to the detector and blowing the speaker and or sound board. I am no electronic whiz, and not even sure which chord to get, or if Escort is correct in their assessment. Here is Sena's help desk response;
"It is quite unusual to hear something like this has happened. I don't believe I have ever heard of an electronics device that has that much power to actually blow out. I will definitely note this to my supervisor and hopefully, we can help us in future cases."
Can anyone help?
Bill, the fact that Escort has an issue in this area is widely known to what Ken would call the MacGyver crowd. Escort's solution is that they sell their own adaptor which is what I use. Its one case in which you can't go wrong using the OEM part. https://www.escortradar.com/store/motorcycle-adapter.html
Thanks so much Chris, your response is invaluable to get me back on track, purchase the correct product, and prevent further damage. Appreciate it!
Chris, and hello everyone
I try the following config, and found out that I still have ground loop noise:
1: connect radar detector, two way radio, SR10 all to the tail ight
2. connect radar detector to tail light, two way radio and SR10 directly to battery
3. connect radar detector and SR10 to tail light, two way radio to battery.
I haven't use any relay when connect to battery since I am only testing if the noise goes away. Basically I can solve the ground loop noise with a simple 3.5mm ground loop isolator and everything I heard will be noise free.
What trouble me is the noise others hear when I push PTT. This noise of couse goes away when two way radio or SR10 is on its battery, as long as they are not on bike power at the same time there will be no PTT noise heard by other rider.
It seems like the 3.5mm audio isolator only isolates ground loop on the signal side. Where SR10's power ground loop still exist and passing noise from SR10 to the two way radio. (I try disconnect the two way radio headset cable which connects to SR10 and the PTT noise also went away when I press PTT on the two way radio itself)
Connecting a power ground loop isolator to the sr10 didn't help a bit in my case, I am guessing that the noise on the power ground is low frequency, and most isolator are high pass filter, not low pass, and it does nothing with my PTT noise issue.
None the less, I saw that you were able to let SR10 auto on/off? can you share the micro USB pin out to make that happen? I want to connect SR10 to my 5VUSB outlet while having auto on/off function. (I am hoping the 12V-5V DtoD regulator will isolate those power ground noise)
PS: I forget to mention, the PTT noise hear by other rider are random, some heard noise when I press PTT, others say I am crystal clear.
Monlin(Mengln), The Sena marketing lingo for the auto on / off feature is somewhat lacking in clarity. Supplying 5V will only charge the internal battery. The "auto" part happens when the SR10 sees 12V... it will turn itself on without pushing any buttons and when you remove 12V it turns off. Any keyed 12V source will work since the circuitry is in the SR10, not the adaptor. The cigarette lighter adaptor does attempt to prevent overvoltage, but that's all. Pin out is here: http://pinouts.ws/usb-pinout.html
The solution i've been using for about 5 months now is to isolate the Sena from the bike power supply using a DC-DC isolation transformer like those built into the very expensive products listed elsewhere in this thread. the device i used is a Tracopower TEL 5-1212:
To buy http://onecall.farnell.com/tracopower/tel-5-1212/converter-dc-dc-5w-12v/dp/1204969
Datasheet: http://www.farnell.com/datasheets/1648716.pdf
Essentially all you need to do is buy a short cigarette lighter extension lead, cut the cable in half, connect the plug section to the to pins 22/2 (positive to 22) and the socket section to pins 14/16 (positive to 14). Once constructed you can just insert ito between the bike and the normal senna bike power kit.
If you dont already own the Sena bike power kit or wish to dispense with it, instead of connecting the cigarette lighter socket to the output pins of the isolation transformer, singly connect a USB lead positive and negative power pins and it will plug straight into the Sena, bike power it and automatically switch on and off with the ignition (assuming the accessory socket it is all connected to is ignotion switched).
If you use this suggestion it essentially breaks the ground loop between Sena and radio - you still need to use the 3.5mm audio isolation cables between the Sena and any radar detectors, GPS etc. Overall the final setup costs about £20.
This works well for me, your milage may vary / caveat emptor etc etc etc.
Matt
Sorry, the buy link should have been to Farnell not Onecall - Onecall is just for eduation.
http://uk.farnell.com/tracopower/tel-5-1212/converter-dc-dc-5w-12v/dp/1204969
Matt
Does anyone know what is the max current draw of SR10 when bike powered [mA] ?
In other words, would 1W, 2W or 3W DC-DC isolation transformed be sufficient, or do I need to go all the way to 5W as Matt has done ?
Sepi
5W will prevent too much heat from the module, since usb 2.0 can draw up to 500mA. I will go higher than 5W if I can but that's the highest they made.
Agree, if you calculate like that 6W would be better, but you are going by USB2.0 spec, not by SR10 spec.
I suspect USB2.0 spec may not be correct in this case when we are talking about 12V since that spec is for 5V only.
So back to my initial question, does anyone know what is the max current draw of SR10 when bike powered [mA] ?
IIRC when paired with a headset, using PTT and charging a flat battery it was peaking around 320mA@12v so just under 4W (with a DMM measuring current on the bike side of the bike power kit). Others may have a more official answer.
As regards 5W being the biggest DC/DC converters Tracopower make have a look at their website. They go considerably larger: http://www.tracopower.com/products/dc-dc-converters/ Other manufacturers also produce similar components, i just happen to have a handy TracoPower 5W one available from another project.
Matt
Thanks Matt, this will do nicely
Sepi
DC isolator/converters works nicely, no more issue.... Sena should consider build this feature within SR10
I purchased the ground loop isolator as suggested by Sena from Amazon. Only problem I had was plastic around male end was a few thousands to big to fit into the SM10 I have. I had to use a nail file to reduce the diameter. Once that was fixed the unit cleared up the issue
David - could you post the link from Amazon that you got your GLI from that Sena recommended. Everyone would appreciate it!
It is the same link that Sena posted in this string of posts early on.
Only $17 with shipping. My only complaint is my left pocket in the Goldwing is filling up with stuff. Batterybug, garage door opener, SM10 and now this but for long trips I want to make sure the SM10 stays charged and have a noise free enjoyment of the Radio and GPS prompts.
Hope this helps.
Thanks Dave, the McGyver approach others had didn't appeal to me at all. I just use the SR/SM 10 on battery as it lasts all day and then some and just charge it from the bike at night right now so I don't have the problem. Maybe I will now wire it up to power and not worry about charging.
I figured for $17 it was worth a try and glad it worked. Like I stated you will have to do a little modification to the male plug end to get the plastic end to fit into your SM10, not sure about the SR10 as I do not have one. I used the edge of a sharp blade to scrape most off the end then used my wife's nail file to get it to the proper size. Hope it works for you as well.
Hi Peter. I've got it mounted under the seat on my Fazer MkII (there's a load of room under the seat). It's in a small plastic box to keep it out of trouble, similar but a bit smaller than the one you can get for the Fuzeblock. The DC/DC converter is mounted on a bit of stripboard (like this http://uk.farnell.com/multicomp/n254-899/stripboard-sngl-sided-0-1inch/dp/9423230) with the wires solder on there as well. Soldering the wires directly onto the pins and then heatshinking them should work perfectly fine too. As long as it stays dry and has some room to dissipate heat you can probably put it anywhere convenient.
If i understand your setup it might be better/easier to put the DC/DC converter in the tank bag and feed it as you are currently doing from the Fuzeblock.
Hi Peter. Yes, by powering them all from the same supply you run the risk of creating another loop. In practice it may be ok but it would be best to just power the Sena from the DC/DC converter.
My solution to my ground loop issue (with a Yaesu FTM-10SR) was hacking up the power cord that came with my SR10 and putting in one of these DC-DC isolated powersupplies that was available from Mouser:
IMO it's a severe design flaw in a device like this not to have ground-loop isolation on all of the audio channels. Next item on the list is to figure out why I occasionally get reports of distorted audio when my SR10 has been on for a while (think it may be a thermal issue).
The SR10 can take 12v in on the USB port (bit of a perversion of the microUSB standard), and it will switch on when it sees 12v there, it will only charge with 5v and you have to power it on manually. The cig-plug that comes with the SR10 does put out 12v, so that's why it turns on when plugged in with it.
Back before my SR10 completely failed, I was powering it off my bike with one of the following isolated dc/dc converters (EC3SA-12S12N) from Mouser and it broke the ground loop. However, breaking the ground loop doesn't fix the issues with distorted transmit audio that I've been hearing on 100% of the SR10's I've seen used.