Car: 1988 Honda Accord
I had a good system going with a farenheight amp, 850 watts. One day it decided to send a thumping noise through the speakers when the car was on. It still hits the beats but theres a constant thump noise (like a bass note).
Obviously I discontinued using the amp. I have cracked it open now about 4 months later.. I'm wondering if you have any suggestions on what I can do to fix it. I'm not sure whats wrong.
I hope this isn't the case, but it was in my trunk, and it has a small leak, it is possible that water got on it and made that happen. I can't see that being the case as it survived so long in that trunk though. Especially since I had it sitting on it's side before the accident, so all the side connections were nowhere near the floor of the trunk.
With the right audio RCA in, theres no thump (but I dont wanna risk doing this to my sub I think that might harm it, its a brand new 5500 MTX, this years model). When the white one is in, the thump comes. I have tried switching the RCAs, same effect. Only happens on the white (left) one. I have hooked it up to two seperate subwoofers and I have tried it on different HUs.
I have little knowledge about car systems, my brother helps me get this stuff fixed. He posted earlier about the ground issue killing the sound in my car yesterday. However, I have had some success with electronics, fixing my computer CD ROM, HU, and some other things that have broke. I am thinking that its just the RCA outlets and I could yank them out and replace them or clean them?
Any help is appreciated,
Brother of 'Black Rob'
Replies (5)
compvr15s on 03/26/2005 22:30:11
are your connections good as far as ground and positive??? if your ground is bad can cause a loop which will give feed back through the amp... id recheck that, and make sure no paint is interfering between the ground and the amp, also make the ground as short as possible... how do you have your rcas and power cable ran.... should run battery cable 4/8 gauge down the one side, and then run the rcas down the other side of the car,they can cause interference when in contact, does the thump get louder if your car is being reved up.... if so try running system with car off but turned to AUX, if sound is gone, then we can go from there, good luck... id think if water damaged the amp it would completly not work, but i may be wrong...
Black_Rob on 03/26/2005 23:59:02
The RCAs and power wire are run down opposite sides of the car. I will recheck the ground connection. What was weird is that i could disconnect one RCA and it would stop making the thump. I'd just leave the Right Channel in and disconnect the Left, and it'd work w/o thumping. Now it is doing it anyway you look at it though.
compvr15s on 03/27/2005 00:07:03
do you know if your rcas are good? do you have a portable discman? if so you can use that to check your amp, you will need to buy a cable like this
http://www.needledoctor.com/s.nl/sc.2/category.215/it.A/id.2089/.f;jsessionid=ac112b1d1f435d8603ca68754928a24b9b0dbfe1eaa5.qQvJq2PEmlnva30P-BbQmkLz-ATzr6Lzn6rzqwTxpQOUc30KaNDNo6XKq6zInRmLa30Q8QzIr6Lyp3aQa2TDpBfG-kfGaNmK8N4SbNiQb34Nbwb48QvJpkixn6jAmljGr5XDqQLvpAe_
then you will need to take a lil piece of wire and run from the pos on your amp to the remote turn on. have your discman plugged into the amp, if your speakers are still thumping then more than likey your amp has some sort of damage.
swez on 03/27/2005 17:36:20
Sounds like the left channel power supply or preamp filters are going south on this amp. If you are brave, can try opening up the casings to expose the circuit boards on this amp and see if you can locate any deformed, chared or unusual components on the board. The most likely problem is a blown filter Cap. These are large, cylindrical devices, located in the main power supply section, close to the toroid transformer coils.
Otherwise, a trip to a good audio repair shop is a good option. Figure about $60.00 labor + parts and 2-3 weeks to get it back.
The walkman test mentioned earlier is a good "isolation test" to see if the problem is in the amp or upstream signal chain. Worth trying as if the noise is gone, problem lies in HU/RCA signal lines.
Swez
lessismorespl on 03/28/2005 20:21:40
Have you tried another amp yet, many times this can also be caused by a short in the preout of the HU. try another amp and see if it still does it, if not, then it is most likely in the amp.
I had a good system going with a farenheight amp, 850 watts. One day it decided to send a thumping noise through the speakers when the car was on. It still hits the beats but theres a constant thump noise (like a bass note).
Obviously I discontinued using the amp. I have cracked it open now about 4 months later.. I'm wondering if you have any suggestions on what I can do to fix it. I'm not sure whats wrong.
I hope this isn't the case, but it was in my trunk, and it has a small leak, it is possible that water got on it and made that happen. I can't see that being the case as it survived so long in that trunk though. Especially since I had it sitting on it's side before the accident, so all the side connections were nowhere near the floor of the trunk.
With the right audio RCA in, theres no thump (but I dont wanna risk doing this to my sub I think that might harm it, its a brand new 5500 MTX, this years model). When the white one is in, the thump comes. I have tried switching the RCAs, same effect. Only happens on the white (left) one. I have hooked it up to two seperate subwoofers and I have tried it on different HUs.
I have little knowledge about car systems, my brother helps me get this stuff fixed. He posted earlier about the ground issue killing the sound in my car yesterday. However, I have had some success with electronics, fixing my computer CD ROM, HU, and some other things that have broke. I am thinking that its just the RCA outlets and I could yank them out and replace them or clean them?
Any help is appreciated,
Brother of 'Black Rob'
Replies (5)
compvr15s on 03/26/2005 22:30:11
are your connections good as far as ground and positive??? if your ground is bad can cause a loop which will give feed back through the amp... id recheck that, and make sure no paint is interfering between the ground and the amp, also make the ground as short as possible... how do you have your rcas and power cable ran.... should run battery cable 4/8 gauge down the one side, and then run the rcas down the other side of the car,they can cause interference when in contact, does the thump get louder if your car is being reved up.... if so try running system with car off but turned to AUX, if sound is gone, then we can go from there, good luck... id think if water damaged the amp it would completly not work, but i may be wrong...
Black_Rob on 03/26/2005 23:59:02
The RCAs and power wire are run down opposite sides of the car. I will recheck the ground connection. What was weird is that i could disconnect one RCA and it would stop making the thump. I'd just leave the Right Channel in and disconnect the Left, and it'd work w/o thumping. Now it is doing it anyway you look at it though.
compvr15s on 03/27/2005 00:07:03
do you know if your rcas are good? do you have a portable discman? if so you can use that to check your amp, you will need to buy a cable like this
http://www.needledoctor.com/s.nl/sc.2/category.215/it.A/id.2089/.f;jsessionid=ac112b1d1f435d8603ca68754928a24b9b0dbfe1eaa5.qQvJq2PEmlnva30P-BbQmkLz-ATzr6Lzn6rzqwTxpQOUc30KaNDNo6XKq6zInRmLa30Q8QzIr6Lyp3aQa2TDpBfG-kfGaNmK8N4SbNiQb34Nbwb48QvJpkixn6jAmljGr5XDqQLvpAe_
then you will need to take a lil piece of wire and run from the pos on your amp to the remote turn on. have your discman plugged into the amp, if your speakers are still thumping then more than likey your amp has some sort of damage.
swez on 03/27/2005 17:36:20
Sounds like the left channel power supply or preamp filters are going south on this amp. If you are brave, can try opening up the casings to expose the circuit boards on this amp and see if you can locate any deformed, chared or unusual components on the board. The most likely problem is a blown filter Cap. These are large, cylindrical devices, located in the main power supply section, close to the toroid transformer coils.
Otherwise, a trip to a good audio repair shop is a good option. Figure about $60.00 labor + parts and 2-3 weeks to get it back.
The walkman test mentioned earlier is a good "isolation test" to see if the problem is in the amp or upstream signal chain. Worth trying as if the noise is gone, problem lies in HU/RCA signal lines.
Swez
lessismorespl on 03/28/2005 20:21:40
Have you tried another amp yet, many times this can also be caused by a short in the preout of the HU. try another amp and see if it still does it, if not, then it is most likely in the amp.
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