Question about Kenwood KAC-728S Car Audio Amplifier

1 Answer

My amp powers on but no sound output..

Hello, My amp powers on yes the LED does light up but there is no sound coming out what so ever no matter what I do with the gain control, switchs etc. I took the amp completly apart and found no signs of burnage or smell anywhere. Now, you say in another post that it is going to be in the preamp stage. Do you have any diagrams in regards to this area and how to fix it?

Posted by on

1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert who has answered 20 questions.


    An expert that hasĀ over 10 points.


    An expert whose answer gotĀ voted for 2 times.

  • Contributor
  • 62 Answers
Re: My amp powers on but no sound output..

My Clarion is doing the exact same thing...and im starting to lean towards a failure in the powersupply of the just cant produce the sound.

Posted on Mar 25, 2007

Add Your Answer

0 characters

Uploading: 0%


Complete. Click "Add" to insert your video. Add


3 Points

Related Questions:

1 Answer

Pioneer GM-6200f amp no audio - flashing light

Hello! Yes, It certainly looks like the output power circuit has blown.

I wish I had better news.


Jan 12, 2010 | Pioneer GM-6200F Car Audio Amplifier

1 Answer

I have a Boss OL5KD Class D Monoblock Amplifier and I set it up but is no sound coming up from the speakers, can anyone tell me how to higher the volumen? where is located the volumen??I need to higher the...

Hello maydude01,

The Boss OL5KD does not have a volume control. It has an "Input Level" adjustment which is used to match the output from your head unit preamp output to the amp. It is the first rotary control just to the right of the input jacks.

If you have no sound at all, I'd suspect that something is incorrectly connected or there is no input to the amp. First make sure that the amp power light (green LED) is coming on when you turn on the receiver and that the protection light (red LED) stays off. Then check all of your wiring, especially the RCA output cables.

Initially set the controls like this: MASTER/SLAVE switch in MASTER position (left). INPUT SENSITIVITY 2v-8v (right). INPUT LEVEL, SUBSONIC FILTER, BASS BOOST, and LOW PASS FILTER; midrange. PHASE SHIFT "0" (left). Leave the remote level control disconnected.

After you've checked all wiring and initially set the switches and controls, turn the receiver on to about 3/4 volume. Now adjust the INPUT LEVEL to the left just until you begin to hear distortion, then turn it back right just a little. Adjust the other controls for best sound. Plug in the remote level control and make sure that it adjusts the bass up and down. You're finished!

If there's still no output from the unit after checking all of the wiring, either the unit is defective, it's not getting an input from the receiver, or the sub(s) are defective.

Hope this helps.

Aug 14, 2009 | Boss Car Amplifiers

1 Answer

Ma audio hk 4000d

you have definately blown a output channel, or power supply. Send it in for warranty.

Jan 09, 2009 | MA Audio HK4000D Car Audio Amplifier

3 Answers

My amp is on but the protection light stay's on!!

Disconnect all speaker wires from the speaker terminals of the amp and disconnect signal cables from the amp. If it powers up, the wiring needs to be checked. If the protect light remains on, the amp likely has blown output transistors.

Feb 28, 2008 | AudioBahn A2801Q Car Audio Amplifier

1 Answer

Xm-6650 led light on short is on and no sound

Disconnect all speaker wires and signal cables from the amp. If it powers up, the wiring needs to be checked. If it still shuts down, the amp likely has blown output transistors.

Dec 16, 2007 | Koiiler XM-6650 Car Audio Amplifier

1 Answer

Green LED comes on then fades out

This is common when the output transistors have failed. The amp powers up and the amp senses a problem and goes into protection mode. Generally, there is a protection LED but not all amps have them. To be sure that the problem is not installation related, check the DC voltage across B+ and ground when the amp tries to power up. If the voltage remains above 11 volts, the problem is almost certainly due to a failed component in the amplifier. Disconnect the signal lines and all speakers (disconnect the wires from the amp terminals) and try to power it up. If it powers up, you could have a defective speaker or defective wiring. If the amp still fails to power up, the amp should be checked by a qualified tech.

Sep 10, 2007 | Crossfire VR402 Car Audio Amplifier

1 Answer

Stop putting out sound to subs

Ok This is a two channel High Current amp. It is stable to one ohm. If the Subs are single voice coil at two ohms the they have to be wired in Parallel that means (Red +) (Black -) are connected to the + and - of another sub and then the (RED +) (Black -) from both go to one output channel of the amp. You pair the other two in the same fashion on the other output channel. If you are getting no output (sound) at all first check if the amplifier is going into protect. (Usually indicated by a red led on the unit. If it is connect only one Sub to each output and see if the protect LED goes out. If it does then you should have sound at the subs. If not check that you have the sub output enabled on the HU some head units do not come with the sub output enabled on the HU. If every thig is enabled, with only one sub connected to each output and the protect LED is not on then your amp is probably blown and needs repair. Nice thing is that MA has a great warrenty policy. Check and make sure the protect LED is off. If it is on you probably have the SUBS wired wrong

Jun 23, 2007 | MA Audio HK802SX Car Audio Amplifier

1 Answer

Amp not putting out sound

This is not a problem that a normal comsumer should try to repair themselves. It's time to take it to a pro. It sounds like you have blown out at least one of your output channels. If you are getting any red light at all then the good news is that the power supply section of the amp is probably still good. About half of all the electronics in your amp is for the power supply section. The other half is for the actual amplifiers of the amp. Good luck, I hope it's not too bad.

Jun 14, 2007 | Alphasonik PMZ12005A Car Audio Amplifier

20 Answers

Amp isn't putting out any sound

I have a Digital Audio model-DA2200W, Was listening to my tunes loud as always....then the subs quit bumpin...checked the subs cuz i thought i blew em...theyre fine...The power on the amp is still light and all..just no output..I opened it up to see if anything looked burnt looks it toast or can i fix it??

May 25, 2006 | Power Acoustik LT-980/2 Car Audio...

Not finding what you are looking for?
Kenwood KAC-728S Car Audio Amplifier Logo

Related Topics:

382 people viewed this question

Ask a Question

Usually answered in minutes!

Top Kenwood Car Amplifiers Experts

Matthew Spark
Matthew Spark

Level 3 Expert

1042 Answers

Tygh Duval
Tygh Duval

Level 2 Expert

290 Answers

Pieter Vleeshouwers

Level 3 Expert

1329 Answers

Are you a Kenwood Car Amplifier Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides