Sound cutting out randomly with the AP16

[youngti]

Okay so I got the new AP16 replacement.  Hooked it up and tested everything works fine.  Then I started testing the two files in the program and something strange is happening.  Let me explain a little about the set-up.  The AP16 is hooked to a Prop1 for a MIB.  I have a 16.5v 7Amp power supply connected to the AP16.  I have two 4ohm 40W speakers (old Auto speakers).  I have two (each) twisted pair of  Cat5e running to the box that goes to the left and right speakers.  I have two wav files Ambient and SFX01.  Program on the Prop1 works as it was intended and the Ambient starts playing.  When triggered the SFX01 starts playing.  Okay so after the first time and sometimes right in the middle of the SFX01 the sound goes fuzzy and goes really really quite. At first I thought that the Cat5e was not strong enough so I replaced it with a direct length of speaker wire.  again worked for a bit then the quite fuzzy sounds started.  Changed out speakers three times with others and finally got it working with one 4ohm.....for a  few triggers, then again same issue the sound goes fuzzy and real quite.  I have a 16Gb class 4 SD card formatted to FAT32 and I ran both wav files though Audacity taking it to 16bit and 44khz then hitting the clear on the metadata a number of times.  I have also tried running the firmware update from site on the AP16.  Not sure what I am doing wrong here but I hope somebody can help.

[JackMan]

Go out and get a Sandisk class 10 SD card. I would be willing to bet your problem goes away.

[youngti]

 I did an 8gbclass 10 and still same issue.

[JackMan]

Is it just the SFX01? Does the ambient file play without any issues?

[youngti]

What happens is both play fine at first.  Then when activated half way through SFX01 the sound will do the fuzzy quiet thing (like a clogged speaker).  Then it will go to the waiting state and AMBIENT will play, sort of, it is also still fuzzy and quiet.  The only way to get it to work correctly is to turn everything off and restart.  Then it may work for 10 to 15 activations. It is random.

[JackMan]

Just a shot in the dark here, by any chance are your speakers grounded? By that, I mean are they in any way connected to the negative side of the power supply or the AP-16?

[JonnyMac]

Have you tried speaker wire? I'm thinking it's a bad idea to use CAT-5 cable for speakers.

[youngti]

From OP  " At first I thought that the Cat5e was not strong enough so I replaced it with a direct length of speaker wire.  again worked for a bit then the quite fuzzy sounds started.  Changed out speakers three times with others and finally got it working with one 4ohm.....for a  few triggers, then again same issue the sound goes fuzzy and real quite"

That was my original thinking but unfortunately not.

[JackMan]

You never answered post #5.

[youngti]

Sorry I didn't see post 5.  I don't think I do have it grounded out.  But for the whole night (just shutting down now) the sound worked flawlessly.  So may be the firmware update did something.  Thank you all.

[JackMan]

Well glad it finally worked. Would be nice to know exactly what the cause was though. I would tend to think it was something other than the firmware.

[livinlowe]

Just a shot in the dark here, by any chance are your speakers grounded? By that, I mean are they in any way connected to the negative side of the power supply or the AP-16?

I would think that if the speakers were connected to the audio jacks or the screw terminals the internal wiring of the AP-16 would make this connnection

[JonnyMac]

I would tend to think it was something other than the firmware.

Me, too.

[JackMan]

Just a shot in the dark here, by any chance are your speakers grounded? By that, I mean are they in any way connected to the negative side of the power supply or the AP-16?

I would think that if the speakers were connected to the audio jacks or the screw terminals the internal wiring of the AP-16 would make this connnection

This is not what you want, that's why I asked. I believe the negative speaker terminals are driven by the amplifiers and not connected to GND. When I checked mine with a meter, there was no continuity between GND and the negative speaker outputs. I'm not sure what would happen if the negative speaker outputs were grounded, maybe Jon can elaborate.

[livinlowe]

Just a shot in the dark here, by any chance are your speakers grounded? By that, I mean are they in any way connected to the negative side of the power supply or the AP-16?

I would think that if the speakers were connected to the audio jacks or the screw terminals the internal wiring of the AP-16 would make this connnection

This is not what you want, that's why I asked. I believe the negative speaker terminals are driven by the amplifiers and not connected to GND. When I checked mine with a meter, there was no continuity between GND and the negative speaker outputs. I'm not sure what would happen if the negative speaker outputs were grounded, maybe Jon can elaborate.

Well, you certainly have me at a disadvantage, as I have no AP-16 lol. I only stated my comment due to the documentation showing no special connections from speaker negative to the power supply negative. But as you've stated, perhaps Jon can elaborate on this aspect of the issue.
When looking through the  docs, I think they stated sound being run through on board relays for ambient sound (?). Perhaps one of these relays was a factory defect ( internal oxidation, yep I'm grasping at straws) and that sound board should be returned with RMA.