Hi Guys,
I'm new here and I would like to fix this my self, so I'm really hoping someone can help me.
I have a Kenwood KAC-X811D it WORKS! but it has very low power output. I think some FETs are gone.
I have it all set up right, gain, volume, speaker, power wire.
I have opened it up and I don't see any physical damage.
I think it might be the power FETs Q57,58,60,61,64,65,67-70
or the amp FETs Q48-51
Do I have to remove them to check them?
I'm new here and I would like to fix this my self, so I'm really hoping someone can help me.
I have a Kenwood KAC-X811D it WORKS! but it has very low power output. I think some FETs are gone.
I have it all set up right, gain, volume, speaker, power wire.
I have opened it up and I don't see any physical damage.
I think it might be the power FETs Q57,58,60,61,64,65,67-70
or the amp FETs Q48-51
Do I have to remove them to check them?
Low volume clean, the display is reading around 3 amps and has a measured voltage of 35. So it sounds and is about 100watts.
Are you sure that the woofer isn't defective?
35v is over 300 watts into 4 ohms and over 1200 watts into 1 ohm.
35v is over 300 watts into 4 ohms and over 1200 watts into 1 ohm.
But at 3 amps its only 100watts. I have no reason to believe the woofer is defective. It seams to me its an amperage problem.
The amp is hooked up 2ohm to a 300watt RMS woofer. If this was working correctly it should be destroying the woofer, but it hardly moves, sounds like ~100watts.
I never thought if I asked for help I would get help from Perry Babin... I have been reading your entire webpage religiously over the passed few months. Thanks!
I never thought if I asked for help I would get help from Perry Babin... I have been reading your entire webpage religiously over the passed few months. Thanks!
Disconnect the woofer from the amp and measure the resistance across the speaker wires. Post the resistance.
I measured it before. I don't have the exact number but it was very close to 2ohms.
The speaker was at 8ohms (Dual 4ohm VC) and it was not very loud, so I changed to 2ohm and no noticeable change in volume.
The speaker was at 8ohms (Dual 4ohm VC) and it was not very loud, so I changed to 2ohm and no noticeable change in volume.
When it was new it was running a 15inch at 2ohms until something happened and it stopped working. The speaker was fried, there was no continuity in the voice coils. I removed the system and put this amp away for years. Now I dust it off and hook it up to a 10inch and its like this, very low output. The 10 is only rated at 300rms, the amp is rated 919rms. Am I crazy? This amp should be pounding! I barley hear it over the stock system. The head unit has 2.5v outs and the gain on the amp is set to around 1.5V just so i can barley hear it at normal volume.
Thought I would double check the ground. Its not the ground. I got 0.4ohm from the ground wire terminal (amp side) to any random bolt in range. I also got 0.4ohm from the -ve battery terminal to any bolt in range. The DMM reads 0.3ohms when the leads are touched.
To determine if the power and ground connections are good, you measure the DC voltage across the B+ and ground terminal of the amp. If the voltage remains well above 12v with the engine running, there isn't a serious problem with the power connections.
When you measured 35v AC across the speaker terminals, was the speaker connected?
Are you sure that you have the positive and negative of the terminals on the speaker connected correctly?
If you connect only one coil, does it get louder?
When you measured 35v AC across the speaker terminals, was the speaker connected?
Are you sure that you have the positive and negative of the terminals on the speaker connected correctly?
If you connect only one coil, does it get louder?
First thing I checked was DC voltage across the B+ and ground terminal of the amp. 12.5V car off. 13.5 with car on.
35v AC across the speaker terminals, the speaker was NOT connected and gain was lower then 2.5V, it was set around 3V.
I have tried changing the +ve and -ve. I will double check.
35v AC across the speaker terminals, the speaker was NOT connected and gain was lower then 2.5V, it was set around 3V.
I have tried changing the +ve and -ve. I will double check.
Speaker wires are fine... all + are attached to +. Amp to speaker terminals. I have also tried to flip the phase switch.
I'm not willing to only hook up one coil... how my speaker is it a lot of work to change that back and forth. I believe it was louder when it was hooked up in 8ohms though.
I'm not willing to only hook up one coil... how my speaker is it a lot of work to change that back and forth. I believe it was louder when it was hooked up in 8ohms though.
Take a 9v battery and connect it across the speaker wires for a few seconds (disconnect them from the amp first). Does that cause the speaker cone to push out or pull in to its limits?
If the speaker barely moves, the wiring is almost certainly wrong on the back of the speaker.
If the speaker barely moves, the wiring is almost certainly wrong on the back of the speaker.
Well, it moved. But it did not go to the limits. Its also installed in a sealed box. Should that have gone to full excursion?
For a woofer rated at only 300 watts, I would have expected it to go to full excursion. If it only moved a tiny bit, I'd suggest either trying a different speaker or using only one coil of the current speaker.
well its a Peak: 600 watts RMS: 300 watts. It moved about half way, 40 to 60%. I have a spare, I will try the other one.
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