Audio cable from Dynon to audio panel

[Cap_Ax]

Can someone tell me where does the audio wires coming out of Dynon harness connects in my audio panel?

I am using a PS Engineering audio panel.

all I could see on the Dynon documentation is the guidance of “these audit out cables go to the audio panel” however I could not find on the audio panel where exactly. Instruction say nothing about it. I realize the audio panel has several input options for things like VOR, secondary radio, and others available. but none indicated specifically for Dynon.

my approach was to just use one of those that I was not going to use or need like VOR for example.

Thank you all

 

[Rhino]

Audio coming out of the Skyview is:
Pin 13 Left audio
Pin 31 Right audio
Pin 30 Ground

You didn't specify your audio panel. But if it accepts stereo input, run pins 13 and 31 from the Skyview to unswitched inputs on the audio panel. If your panel only supports mono audio input, twist the wires from pins 13 and 31 together, and run them to a single unswitched input on the audio panel. According to PS Engineering, the ground should only be connected on the audio panel end of the harness. They say to leave the other end floating.

As an example, on a PMA6000B audio panel, the unswitched inputs should be on pins 7 and 22. Other audio panel models may differ.
Their install manuals are available here:

PS Engineering Inc - Downloads

PS Engineering is the leading innovator in audio control systems for general aviation and special mission aircraft.

www.ps-engineering.com

Wiring diagrams are typically near the end of the install manual.

 

[Stevec]

Hi Rhino that is not quite correct. The 6000B is a mono audio panel and the correct connections are to twist the left and right outputs from the Dynon together and attach them to pin 7. The audio ground ,pin30, from the Dynon should be connected to pin 24 on the 6000B. The screen or shield should only be connected at the audio panel end and should be connected to the ground lug on the mounting tray which in turn should be connected to the aircraft ground.

 

[Cap_Ax]

the PS panel I have is Stereo, PMA8000G Flightmate which is Stereo capable. So instead of twisting, the third wire would go to which Pin?


Ground Pin 30 from Dynon to pin 24 on PS

Pin 13 Left audio from Dynon to pin 7 or 22 on PS (unswitched)

Pin 31 Right audio from Dynon to pin ??? On PS

i have the PS diagram but it’s incredibly small and terrible resolution, so hard to see…
Thank you all!

 

[Rhino]

Hi Rhino that is not quite correct. The 6000B is a mono audio panel and the correct connections are to twist the left and right outputs from the Dynon together and attach them to pin 7. The audio ground ,pin30, from the Dynon should be connected to pin 24 on the 6000B. The screen or shield should only be connected at the audio panel end and should be connected to the ground lug on the mounting tray which in turn should be connected to the aircraft ground.

Not sure what you think isn't correct. You just repeated essentially the same thing I said, except that PS Engineering says not to connect the ground to pin 30 at the Skyview end.

 

[Rhino]

the PS panel I have is Stereo, PMA8000G Flightmate which is Stereo capable. So instead of twisting, the third wire would go to which Pin?


Ground Pin 30 from Dynon to pin 24 on PS

Pin 13 Left audio from Dynon to pin 7 or 22 on PS (unswitched)

Pin 31 Right audio from Dynon to pin ??? On PS

i have the PS diagram but it’s incredibly small and terrible resolution, so hard to see…
Thank you all!

Although the PMA8000G is a stereo audio panel in the sense that it supports stereo headsets, the wiring diagram does not indicate that it supports unswitched stereo inputs. I'm guessing the stereo function is only in reference to it's ability to send different sources to different ears to provide a spatial function, what PS Engineering calls IntelliAudio, rather than an ability to input stereo audio from a single source. Based on the wiring diagram, you would twist the wires from pins 13 and 31 from the Skyview together, and connect them to any unswitched input on the PMA8000, which would be your choice of pins 29, 31 or 44. Do not connect pin 30 on the Skyview to any wire. PS engineering says the ground wire should only be connected on the audio panel at pin 43. Although the diagram says to see notes 6, 10 and 11 for the unswitched inputs, note 1 is where it addresses the ground wire.

EDIT; See the correction in post #8 below.

 

[Rhino]

Would this help? This would connect to unswitched input #1 on the PMA8000. You'd use a different pin for inputs 2 or 3.

 

[Rhino]

Okay, I think I see what Stevec was trying to get at. Dynon and PS Engineering use different terminology, and apparently different wire standards, to make their diagrams. PS Engineering refers to the secondary audio line as Audio Lo, and Dynon refers to it as Audio Ground. It also seems PS Engineering is assuming the use of unbalanced audio wiring, where the shield ground doubles as the Audio Lo wire, and Dynon recommends using balanced audio cables, where the ground is a shield that surrounds two separate wires for the Hi and Lo audio signals. It's the chassis ground that PS Engineering only wants you to connect at the audio panel. You do want to connect Audio Ground on the Dynon to Audio Lo on the PMA8000. So I deleted the diagram I posted above. This should work instead:

The unswitched connections are still mono audio though. To use the stereo capability of the PMA8000G, you'd have to utilize one of the two stereo music inputs it has. I've never actually seen anyone do this with an EFIS, but I see no reason why it wouldn't work. One potential drawback is that music inputs will probably automatically mute when a radio call is heard. If that's the case, you wouldn't get any audio from the Dynon when a radio transmission is received, but that may not matter to you. The two music inputs are labeled as Entertainment (Ent) on the wiring diagram, and they're actually on a different connector (J2 instead of J1). If you want to try this option with Entertainment Input #1, it should work if you connect as below (no guarantee):

 

[jakej]

I would like to add that just because the shield is not shown it is still the norm for all audio wiring to be shielded & as Rhino says the shield should be grounded at the Intercom/Audio panel end only, that is the generic way to do audio wiring. (as an aside - look at the Apollo manuals. they show grounding at both ends - go figure !)
Dynon audio to Audio panel - One method is to connect it to an unswitched input or an unused switched input eg ADF, Nav 2 or Com 3 etc - that means you can switch it off when doing aerobatics for example.

 

[Rhino]

The differences in grounding principles are in many ways related to advancing technology. Ground loops are a commonly seen problem on aircraft, and always have been. Floating grounds have also been an issue. Those are mostly electrical system issues. But audio introduces a whole new realm to the equation, and is very often affected by electrical system issues. Sometimes the grounding problems are alleviated by getting creative and changing what gets grounded where (usually assuming you didn't do it correctly in the first place). That's why a lot of avionics manufacturers established their own particular preferences over the years. But it got even more complicated with audio wiring when shielded and balanced audio cables started becoming a standard. The grounding philosophy was different, so you'd see different recommendations from different manufacturers, based in large part on whether or not they expected you to use shielded, balanced cables or unbalanced cables. Apollo is a great example. They've been around for a long time, and their practices are ingrained based on years of experience with older equipment and cabling schemes. Most often it works just fine with newer equipment and cabling, so they see no need to change what they recommend. And in some cases the old methods actually work better (aircraft are fickle). In this case I'd just go with what PS Engineering recommends, and then get creative with other ideas if things didn't work out so well. Unfortunately, it seems this approach can be more common that you might think. No two aircraft are alike, especially in the experimental world, and what works with audio on one plane often doesn't work well at all on others. Welcome to homebuilding!

 

[Stevec]

I agree with Rhino based on my latest instal. With my previous setup, not done by me, an A200 radio and PM1200 intercom I had many issues with noise from my Dynon screens. There was a cycling whooshing noise present in the background and no amount of earthing , or rerouting wires seemed to fix it. I upgraded to dual Icom radios and a PMA6000B and followed the recommendations of PS engineering. The result was an absolutely noise free audio setup. One issue that I did notice was that the Dynon recommends using shielded cable in their installation manual yet their supplied harness just comes with plain wire. I suspect that they feel twisting the wires together provides sufficient protection from induced noise. My compromise was to keep the plain wires as short as possible and after joining the two SV screens together I ran screened cable to the audio panel.

 

[Rhino]

Given the short distance between dual displays, you aren't likely to see a noise problem there unless the cable is routed close to other wiring. Another difficulty with manufacturer terminology is there's no universal, published standard for audio wiring like there is for something like USB cables. That's probably why so many people refer to the same wiring schemes with different labels. They're perfectly free to label them as audius maximus and audius minimus if they want to, and there doesn't seem to be any great effort to get everyone to use the same standard. The different cable options don't make it any easier.

 

[Rhino]

Essentially all the meat of my discussion in a pdf file:

 

[Speeddog8]

OK, since you guys clearly know your S#%t about audio. I’d like to run my issue by you. I connected a PM3000 to a couple of HDX’s and if I recall, I connected the shield direct to the audio ground on the HDX (which I’m sure is already grounded on the PM3000. Below is my issue:

“I recently built a new panel for my airplane. Removed old Dynon equipment and installed new dual HDX system, AP, etc. The only components of my old system that I retained from the original panel wiring was the SL-30 Nav Com and my intercom. I didn’t mess with any of that wiring with the exception of locating the stereo inputs and ground from the PM3000 intercom and connected them to each of the Dynon 37-Pin harnesses. I got everything working and ready for a test flight, but then noticed that it appeared the squelch on the SL30 was on. I could hear people in the pattern and I could transmit to them. They said I was loud and clear, but I couldn’t resolve the loud squelch in my headset (Bose with aviation plugs, same headset and jacks I’ve been using for years in this aircraft). I adjusted the squelch in the intercom and adjusted some settings in the SL30, but still could not resolve the issue. I decided to turn the volume on the radio down low and go for a flight regardless. After flying for about 10-minutes, I noticed that the problem had resolved itself. The com acted perfectly normal, no squelch issue whatsoever. The next day, I pulled the plane out and had the same problem, but I didn’t go fly. Any idea what the problem might be? Sounds like a settings issue, but I can’t figure it out”.

Could my intercom shield ground at the HDX harness be my problem? Any input you might have would be very much appreciated.

 

[Rhino]

It's unlikely the ground you mention is causing your problem. That usually causes an induced noise issue, and you appear to be having a squelch problem on your radio itself. Just as a clarification, it sounds like you're getting full static from the radio when this problem occurs, and no amount of squelch adjustment changes that. Is that correct, or do you think this might be some sort of system noise bleeding into your audio lines? A bad ground won't usually cause the former, but can easily cause the latter, so it's important to understand exactly what you're experiencing.

Given the scenario you depicted, I'd lean toward a bad connection somewhere. The fact that it eventually went away and then returned suggests it may be temperature dependent, and bad connections oftentimes are.

My first step in this would be isolation. The next time you experience this problem when not airborne, start turning off individual equipment items, beginning with the radio itself, and leaving the intercom until last. Determine exactly when the problem goes away, and that will help isolate the cause. At the very least, it will give better clues to go on in locating the source of the problem.

By the way, there are four different models of the PM3000, and two different wiring diagrams in the installation manual on PS Engineering's web site, depending on which model you have. Your diagram seems to indicate you have the six place intercom, part number 11932 or 11934. If you have the four place intercom, part number 11931A or 11934A, you have unswitched audio inputs that the six place model doesn't have. If that's the case, alert audio from the HDX should be going to one of the unswitched audio inputs, and not the music input. The only advantage a music input gives you is stereo, but the HDX doesn't output stereo unless you have twin engines and/or dual engine EMS modules.

 

[Rhino]

Almost forgot. Did you by any chance install an aux headphone jack on the PM3000? That gives you the ability to bypass the intercom entirely, and remove it from the equation when troubleshooting.

 

[Rhino]

Oh, and does this only occur with the engine running?

 

[Speeddog8]

Rhino, You’ve given me a lot of homework, but I’m 90% certain my intercom is a 4-place model, not six. I’ll have to verify the specific model. I have three headphone jacks installed in the airplane as I have a small jump seat in the back. The music input from this intercom used to go to a music input mini- jack that I’d plug my iphone into for music, but now that I have Bluetooth headsets, I removed that jack and instead connected those same music input wires to the Dynon 37-Pin connector including the shield for ground. I’m getting the audio alerts from the Dynon just fine. Even without the engine running, I have a bit of low level hum and clicking in my headset. I need to do a bit more testing, but in the hangar tonight, the squelch issue didn’t occur. I can pull the SL30 squelch knob out and got squelch, so I’m inclined to say that the problem squelch issue only occurred the other day when the engine was running. Also, to answer you initial question. Yes, I’m getting full static from the radio, not system noise (aside from what I just described above). While installing the HDX, I plugged in and listened numerous times with my headsets along the way and never encountered this squelch issue, so I’m inclined to say that the problem only occurs with the engine running. I’ll get that tested shortly. What do you mean by “aux headphone jack”? Btw, thank you for your response. I really do appreciate it!

 

[Rhino]

Go to the PS Engineering web site and download the current installation guide.

https://www.ps-engineering.com/assets/docs/PM3000_IM.pdf

It has two different diagrams, for four place and six place versions. Since the diagram you posted doesn't have the same text at the top indicating which part number the diagram applies to, I suspect you don't have a current manual. Either that or PS Engineering simply opted to send you a single diagram with your intercom.

This is from the 4-place intercom diagram, except I shrunk it a bit to make it fit better here;

Pins 14, 12 and 25 are for an auxiliary jack that can bypass the intercom. Although those pins do connect to the intercom, they also go directly to the radio. It's purpose is to allow direct use of the radio when the intercom fails, or to bypass the intercom for troubleshooting. It can operate your radio even with the connector completely removed from the intercom. So if you have that jack installed (not everyone uses it), it might help in isolating your problem here. Some people who install this jack don't actually put it on the panel. They just leave it hanging on the wiring harness behind or under the panel so it doesn't take up panel space. If you weren't the original installer, it's possible there's an auxiliary jack hiding somewhere.

You can use a music input for alert audio from the HDX if you want to, but your intercom has an automatic mute function on those inputs. Your alert audio will be muted anytime the radio is sending or receiving a transmission, whether the transmission is directed at you or not. Essentially. whenever anyone keys a mic on the radio frequency you're tuned in to, your alert audio gets turned off. You'll still see alerts on the screen, but you won't hear them. The PM3000 does allow you to disable the mute function by pressing the squelch button in (karaoke mode), but that may be a 'soft key' you'd have to activate every time you turn the intercom on. Again, this is user choice, and some people don't care if their alert audio mutes. But when you have unswitched connections available to prevent that from happening (you have two unswitched inputs), I don't see why you wouldn't use them.

And since we're on that topic, when you say you're 'getting squelch' when you pull the knob out, do you mean you're getting radio static when you pull it out or push it in? If so, I don't think it's radio static. The squelch functions by rotating the knob. According to what I see in the user manual, pushing it in simply enables or disables the mute function for the music input. That would mean your static is coming from your music inputs, not your radio. You can simply disconnect the music (entertainment) inputs on the intercom, pins 24, 11, and 18, to confirm this.

PS: I've edited this post a couple of times, so make sure you didn't miss something I may have put in after you initially read it.

 

[Speeddog8]

Go to the PS Engineering web site and download the current installation guide.

https://www.ps-engineering.com/assets/docs/PM3000_IM.pdf

It has two different diagrams, for four place and six place versions. Since the diagram you posted doesn't have the same text at the top indicating which part number the diagram applies to, I suspect you don't have a current manual. Either that or PS Engineering simply opted to send you a single diagram with your intercom.

This is from the 4-place intercom diagram, except I shrunk it a bit to make it fit better here;

View attachment 5288

Pins 14, 12 and 25 are for an auxiliary jack that can bypass the intercom. Although those pins do connect to the intercom, they also go directly to the radio. It's purpose is to allow direct use of the radio when the intercom fails, or to bypass the intercom for troubleshooting. It can operate your radio even with the connector completely removed from the intercom. So if you have that jack installed (not everyone uses it), it might help in isolating your problem here. Some people who install this jack don't actually put it on the panel. They just leave it hanging on the wiring harness behind or under the panel so it doesn't take up panel space. If you weren't the original installer, it's possible there's an auxiliary jack hiding somewhere.

You can use a music input for alert audio from the HDX if you want to, but your intercom has an automatic mute function on those inputs. Your alert audio will be muted anytime the radio is sending or receiving a transmission, whether the transmission is directed at you or not. Essentially. whenever anyone keys a mic on the radio frequency you're tuned in to, your alert audio gets turned off. You'll still see alerts on the screen, but you won't hear them. The PM3000 does allow you to disable the mute function by pressing the squelch button in (karaoke mode), but that may be a 'soft key' you'd have to activate every time you turn the intercom on. Again, this is user choice, and some people don't care if their alert audio mutes. But when you have unswitched connections available to prevent that from happening (you have two unswitched inputs), I don't see why you wouldn't use them.

And since we're on that topic, when you say you're 'getting squelch' when you pull the knob out, do you mean you're getting radio static when you pull it out or push it in? If so, I don't think it's radio static. The squelch functions by rotating the knob. According to what I see in the user manual, pushing it in simply enables or disables the mute function for the music input. That would mean your static is coming from your music inputs, not your radio. You can simply disconnect the music (entertainment) inputs on the intercom, pins 24, 11, and 18, to confirm this.

PS: I've edited this post a couple of times, so make sure you didn't miss something I may have put in after you initially read it.

I confirmed that I do have the 11931A version of the PM3000.