mtx thunder 6500D pulsating

[BrownVanMan 10+ year member]

i go to set the gains and as soon as i turn it up it starts puling loud. cant get more than 10 volts AC out of it. at the time it get 14.1volts then starts freaking out and drops to 12. the red light on top of the amp blinks for a few seconds after i turn gain down to quiet it. im gonna try to change out to a different amp(less power) to make sure its not some werid rca problem. im trying to get 600 rms out of it at 2 ohms.

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[mike49504 10+ year member]

SOunds like you have internal problems with the amp . The following could be wrong

1:Bad output transistors

2:Bad op-amps

3: bad gain pot

4: an open ground shield either in the amp or the head unit itself.

I repair amps if you want to have it checked out after you determine if its the amp.

 

[Louisiana_CRX 5,000+ posts]

bad ground....

 

[morespl 10+ year member]

i go to set the gains and as soon as i turn it up it starts puling loud. cant get more than 10 volts AC out of it. at the time it get 14.1volts then starts freaking out and drops to 12. the red light on top of the amp blinks for a few seconds after i turn gain down to quiet it. im gonna try to change out to a different amp(less power) to make sure its not some werid rca problem. im trying to get 600 rms out of it at 2 ohms.

check your speaker wires and all connections how many speakers are running off it.

 

[BrownVanMan 10+ year member]

2 12s. down to 2 ohm. and i know the ground is iffy atm. ill reground tomorrow and report back. also i have not big 3'd the car yet.

 

[morespl 10+ year member]

check the bridging on the speakers some times they have a loose connections might even touch I seen the same thing happen to a mtx 9500 the terminal cups melt and the amp would cut out and do all types of stupid stuff before we realized what was going on.

 

[BrownVanMan 10+ year member]

ill give it a good look tomorrow. i have been using it a few days just not turning it up/tuning sub lvl down.

 

[BrownVanMan 10+ year member]

ok so now my ground is for sure good. voltage gets to 13.8 before amp goes nuts and then they drop to 12.6. when on the speaker side of things i can slowly turn gain up ge to about 12-15 volts then it freaks and goes to 45-48. so im thinking amp is bad. could it have been mishandled and something on the board broke?

 

[Spooney 10+ year member]

I think it is a good bet that your rca shield ground has an intermittent or broken connection. These amps are notorious for that. MTX amps have been famous for this issue since the original Thunder series amps. If you don't get it taken care of you will blow the sub connected to it and the amp as well.

 

[BrownVanMan 10+ year member]

have a diagram of what that would look like. ill shut the amp off via the HU then uninstall it once the temp get above 10 degrees.

 

[Spooney 10+ year member]

If you jiggle or push the rcas around does the noise stop or change? Does turning the gain up or down have any effect on the noise? I will try to find a pic of what I think the problem is.