I have a KX2500.1 that was completely blown up so I rebuilt it. I noticed though with no input, theres a strong audible hiss from the speaker. like a waterfall. (This speaker is full-range btw).
I have not had this before when working on these amps, I removed the pre-amp board and no more hiss. So the problem is in the preamp.
I replaced both TL074C chips but the noise is still the same, not sure what's going on there.
I suppose the good news is, I can finger the LM13600 and listen to the radio station across the street :-D
Short of replacing the LM13600, I am not sure where to go with it. I did scope the output of OUT, and I can see the noise. it looks like an oscillation of around 13Mhz bursts repeating.
I have not had this before when working on these amps, I removed the pre-amp board and no more hiss. So the problem is in the preamp.
I replaced both TL074C chips but the noise is still the same, not sure what's going on there.
I suppose the good news is, I can finger the LM13600 and listen to the radio station across the street :-D
Short of replacing the LM13600, I am not sure where to go with it. I did scope the output of OUT, and I can see the noise. it looks like an oscillation of around 13Mhz bursts repeating.
Yeah it has the 5 pin header. I was thinking about bypassing it, just trying to figure out a safe way to do so
I've never seen this failure mode and this is a strange IC. If you'd have to order it (and nothing else), give me the voltages on all of the terminals and I'll see if anything is obvious.
If the repair discussion is taken away from the forum, at least post the solution to the problem so others may be helped by it later.
Replaced it with the NJM13700, hiss is still there. Only goes away if I remove that chip and bypass it. If i simply remove the chip and not install a jumper wire, that same hiss is still there. Removing the preamp board entirely also removes the hiss.
Leads me to believe its switching related. Not sure though, and it feels like something I can spend hours on chasing my tail with little return, as this is a hobby for me now and not a day job.
Amp started life off completely blown up with water damage, i fixed all of that and even had to clean up the damaged PCB and replace a few caps in one of the 12V regulated supplies.
Not sure where to go in from here, my scope cant really see any noise coming from the preamp, but the probe is picking up residual switching noise from simple inductive coupling somewhere
Maybe this hiss is normal on the KX2500.1 from 2004? I found other threads in this forum with no real solutions either so I am not the only one with the problem.
Here is a video i took demonstrating the problem:
Leads me to believe its switching related. Not sure though, and it feels like something I can spend hours on chasing my tail with little return, as this is a hobby for me now and not a day job.
Amp started life off completely blown up with water damage, i fixed all of that and even had to clean up the damaged PCB and replace a few caps in one of the 12V regulated supplies.
Not sure where to go in from here, my scope cant really see any noise coming from the preamp, but the probe is picking up residual switching noise from simple inductive coupling somewhere
Maybe this hiss is normal on the KX2500.1 from 2004? I found other threads in this forum with no real solutions either so I am not the only one with the problem.
Here is a video i took demonstrating the problem:
With Kicker, I'm not the best option. Are you going to get any more help offline? If not, we can try a few things.. which may be a waste of time.
I retract the earlier statement. If i completely remove the pre-amp board, the hiss is still there but its just barely audible.
Offline >> off of the forum. Probably not the best of descriptions.
This is a subwoofer amplifier. Is the hiss so bad that you hear it through a subwoofer?
Is it a constant hiss or a whining sound that varies in frequency?
This is a subwoofer amplifier. Is the hiss so bad that you hear it through a subwoofer?
Is it a constant hiss or a whining sound that varies in frequency?