PA D5000.5 Amp Buzz (even when RCAs unplugged; disappears when sound is played)

[Copied from Troubleshooting Section]

Hi Guys! I need advice. I just received my PA D5000.5 amp from Amazon and installed it just a few hours ago. Before the installation of the PA D 5-channel amp, I had another aging temporary 4-channel non-polk local amp to power my MM6501 seps (front) and DB651 coaxials (rear). With the temp amp, I had no noise besides the high-pitched powering off sound when amp is turned off :exclaim:

But with the PA D5000.5 amp, I'm getting some buzz/hiss/whine even if:

1) Radio is OFF (same scenario if my volume is set to 0 or fader/balance set to extremes)
2) RCA inputs are NOT plugged to the amp
3) Engine is OFF (I get engine whine in addition when engine is on).

Here's the thing: when I turn on the radio and adjust the radio volume/fader/balance so a speaker plays a sound. The hiss from that particular speaker is gone even I turn the radio off afterwards (and on again) or just the particular speaker using fader/balance controls. This is true even when I start the engine :idea:

But any speaker that hasn't played a sound since initially switching the car from OFF to ACC will have the hiss/whine :exclaim:

The noise doesn't increase with the volume.

NOTE: My remote on wire is connected to the car's ACC so the amp turns on immediately. Unfortunately, my factory head unit doesn't have a remote out.

But then again, with the temp amp, it doesn't matter, I don't have this noise at all.

What's wrong with my all Polk setup?

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[UPDATE] I have some more points that I found out about my issue:

1. Let's say the car is on ACC with my HU off and I am getting this buzzing sound. If I open the driver-side door, I get this alarm that my key is still in the keyhole. Pretty normal, right. But once I close the door, the alarm stops.. AND so does the buzzing from speakers :exclaim:

2. After two hours of driving with stereo on (moderate levels most of the time with some elevated levels towards the end), I checked the amp. The PA D5000.5 is hot to the touch (not scalding but I can't keep my palm on it for more than 3 seconds). Now, this is a class D amp and I believe my temp amp is a class A/B amp and its freaking huge, but I never felt it this hot.

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I'm speculating maybe since its turned on immediately even without any signals from the RCA inputs, the amp trying its darn-est to amplify whatever signal its getting from the environment?And maybe since the signal is so weak, it's using a lot of power to make it audible (buzzing sound). Anyhow, I'm just guessing at this point. Any help is highly appreciated.

Previous Amp:

http://imageshack.us/a/img846/92/120130112080845.jpg

New Amp:

http://imageshack.us/a/img13/95/620130112081144.jpg

It sounds like a faulty amp especially with it doing the same even with the RCA's unplugged. But with all the other issues it sounds like there is some really bad wiring somewhere.

One way to check if you dont have a buddies car you can hook it up to real quick, would be to disconnect the battery completely from the car. Now take the amp and hook its + and - straight to the battery and then take a speaker (an extra one lying around would be best but take one from the car if you dont have one) and hook it up to the amp. If you still get the buzzing despite the amp being totally isolated from the car, then you know its the amp that is shot and you need to contact Polk customer service. If you dont get the noise then its a wiring issue inside the car. Normally Id say thats not the issue but when you say your old amp had some weird high pitched whine when it shut down along with all the weird stuff your car is doing, it is a possibility.

thanks MacLeod, i'm already scheduled to do the amp check with my installer soon to check the amp as you suggested :idea:

for the purpose of discussion though: others suggested that it is an issue with my remote turn on. because if i have the ideal remote turn on, my amp would just turn on when the HU is actually on and the HU is pushing signals to the amp so i wouldn't encounter the issue.

here's their exact words:

Quote:

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If I would venture a guess, I would think that it may have something to do with the input automatic gain. With no signal coming in initially at the inputs, the amp may have automatically increased the gain to compensate. But when you turned on the radio, the amp readjusted the gain to a lower level, almost eliminating the white noise.

As with the connection with the door closing, I would think that there was enough spurious or transient noise coming into the input, possibly caused by the dome light control circuit, to introduce a "pop" into the amp input and allowing the input gain to adjust its level.

The best workaround is to somehow tie up the remote power to the HU.

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the logic seems solid. what do you guys think? is there something like "automatic gain adjustment" on amps? :question:

additional questions:

1. does anyone know the standard operating temperature range of a class D amp or this particular PA D5000.5 amp?

2. i don't have anything connected to the sub input and sub speaker output or the 5th channel on the amp right now. my sub isn't here yet. is this okay or can this cause my issues?

I'm not smart enough to know the inner workings of amps so I don't know about "auto gain adjustment". I've never heard of it.

Don't know the temperature and running without a sub wont hurt the amp but go ahead and plug the RCA's in though. Some amps don't like running with some channels unplugged.

Just an update guys, hoping someone can give suggestions?

So I went back to the installer for subwoofer installation and at the same time, get them to help me resolve my issue.

The first thing we did was remove the amplifier from the car and connect it to a test speaker and battery away from the car. Each individual channel was good and no noise. So that rules out the amplifier :idea:

When brought back to the car and connected to my speakers and power connections, the noise is there, obviously.

So I wanted to pin-point the issue so we tried different combinations when the amp is already connected to my car's audio setup and found out that if the amplifier's power, ground and +12v remote are directly connected to an external battery, the static noise is NOT present.

However, when the amplifier's power and ground was connected to the external battery BUT the +12v remote was connected to my car's ACC, the noise was there. This led us to a faulty conclusion that its a problem with my remote write connected to the car's ACC tapped from the HU, so I asked the guy to tap the remote wire to another source directly in the fuse box. To our hearts dismay, the problem was still there :confused:

Next, we tried connecting the ground directly to the battery using jumper cables hoping to eliminate any grounding issues. The noise was still there. However, now that I am reflecting on it, the guy connected the jumper cable to the end of my existing ground wire. Were as when we connected the amplifier to the external battery, we used a different set of wires.

I might go back and ask them to use the jumper cables directly and use a new set of power wires to eliminate if its my power and ground wires and their placement :idea:

Any more troubleshooting ideas is certainly appreciated :arrow:

PS. The guy used a volt meter to check the voltage of the power+ground and the remote+ground, the result came up with a stable +12.4v.

I may have missed reading it, but have you checked all your speaker connections to make sure they are not contacting metal/ground? Also, check your speaker wire runs for any exposed/pinched areas.

If the amp is noise free when power, ground and remote are being fed from another battery, youve got something wrong with the wiring and most likely the ground. First off, make sure the amp is not screwed into metal. If it is, this could cause a ground issue and induce all kinds of noise. You want to have the amp screwed into something thats not connected to the chassis or at least to a piece of MDF.

If youre set there then its time to try another ground location.

First of all, thanks for continuing to help sort out my issues :exclaim:

Quote:

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Originally Posted by 1996blackmax

I may have missed reading it, but have you checked all your speaker connections to make sure they are not contacting metal/ground? Also, check your speaker wire runs for any exposed/pinched areas.

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there's no noise when i'm playing music so i'm fairly certain it's not my speaker connections. moreover, the static noise is coming from all speakers.

Quote:

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Originally Posted by MacLeod

If the amp is noise free when power, ground and remote are being fed from another battery, youve got something wrong with the wiring and most likely the ground. First off, make sure the amp is not screwed into metal. If it is, this could cause a ground issue and induce all kinds of noise. You want to have the amp screwed into something thats not connected to the chassis or at least to a piece of MDF.

If youre set there then its time to try another ground location.

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I'm going to schedule another round with my installer. I paid relatively huge sum to get this setup so I will insist they help me fix this issue. I just ran out of time last time and I was running out of ideas.

My current amplifier ground wire is connected to the chassis to a factory grounding point. Also in the same ground point, is some stock ground wires and the ground of the newly installed AudioControl LC2i LOC. Unfortunately the LC2i, great turn-on feature is not working for me :sad:

So any more suggestions/ideas are appreciated so we will all try them out on my next appointment :idea:

Didn't know about the LOC. I'm now thinking that is the source of your problem. That amp has speaker level inputs. Try tapping the factory speaker wires straight into the amp and disconnect the LOC and see if your noise goes away.

Unfortunately, the PA D5000.5 doesn't have speaker level inputs. It only has RCA inputs.

Also, the static noise is there even when the RCA inputs are not connected which should rule out my HU as well as my LOCs.

I coulda sworn the 5000.5 had speaker level inputs. Guess I should pay attention more.

Unhook that LOC completely. Unhook its power, ground and everything and see if the noise is still there. Since its remote isnt working, Im thinking that it might be faulty and inducing noise into the system. Longshot but you never know.

I uploaded an MP3 file for you guys to hear the noise yourself: Playing: Static Noise - Door Open-Close.mp3 - picosong

Here's a summary of the significant events by time:

0:02s - I switched the key from OFF to ACC
0:08s - Amp clicks ON
0:09s - Static noise comes to life! :mad:
0:14s - Opened the driver-side door
0:15s - Annoying but perfectly normal door alarm
0:18s - Closed the door
0:19s - Static noise gone! :exclaim:

The entire time the head unit is OFF. If I turned ON the HU and it starts sending signals, the same effect as the door closing will happen.

More pics to help visualize:

Battery Connections
http://imageshack.us/a/img19/3473/16...9105643.th.jpg

Active LOC sourcing fronts and sub
http://imageshack.us/a/img5/6194/192...9114205.th.jpg

Gauge 4 Power and Ground Wire
http://imageshack.us/a/img248/3103/audiomaxwires.th.jpg

Amp Ground Location
http://imageshack.us/a/img255/1011/0...9103856.th.jpg

We used the same ground location. Right now, the same grounding point we use for (1 being the closest to the chassis):

1. Amp Ground (Gauge 4)
2. Active LOC (Gauge 18)
3. Factory Ground for something (we don't know what)

Power and Ground
http://imageshack.us/a/img203/9788/1...9103949.th.jpg

I asked them to add a chassis-to-negative-battery connection on the other side of the stock position. We used the same bolt as the bolt for the alarm siren.

Power wire crosses the engine along the firewall and runs through factory grommet on the passenger side leading to the back of the glove compartment.

Amp Position
http://imageshack.us/a/img10/2712/07...9103740.th.jpg

Amp positioned nder the passenger seat. Amp ground wire runs more or less than 1 yard from amp to chassis.

I can post more pics if necessary :idea:

Additionally, a guy posted this in another forum:

Quote:

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Try installing filter capacitor around 0.1 microfarad in your remote wire. This is to bypass high frequency signal ( hiss ) to ground of your Remote Wire. This will help cleaner Remote Wire.

But if hiss noise still persist.

Try installing separate high current relay for your amplifier as dedicated power source and use bigger gauge wire. Ground wire connection must be also in the battery - terminal. Don't forget the fuse.

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Worth a try?

I'm out of ideas man. It's either a problem with the power, ground or remote wire. You've eliminated everything else.

No worries man and thanks for all your help MacLeod :wink:

[UPDATES]

OK, we tried connecting the external battery again to the amp, as was before the static noise on power up isn't there. Then we tried moving the grounds around the car, no effect.

I don't understand the issue since once the HU starts playing, there's no noise the sounds are crisp and clear in all of my speakers including the subwoofer It's just annoying :frown:

I'm going to leave it as is until I have free time again or get a new HU with a dedicated remote turn-on wire. That should solve my turn-on problem. Too bad this AudioControl LC2i's Great-Turn-On feature didn't work with the stock Kia HU. Well, they did advertise that it might not work with some factory HUs especially ones that use the sound system for other system purposes.

I still say try it with the LOC completely disconnected. I know its a long shot but maybe its defective and is inducing a crap load of noise thru the grounds that your amp is picking up. Its the only thing I can think it could be. Its gotta have something to do with the LOC since the sound stops once you fire up some music.

Time to service that baby