Sub cutting out?

[Cpt.America]

Hey guys, i need some help figuring out what is wrong.

I came home today and put a cD in. I quickly realised that I wasn't getting anything out of my sub (eD a3-300). I thought maybe it got turned off. But, nope. Its plugged in turned on, but the l.e.d. light on the amp stays red. If i turn off the switch... turn the volume on the sub amp way down... and turn it back on, the L.E.D will be green and I will get music out of the sub... the as I turn the sub amp up, as soon as it is near normal play levels and I get a little thump from a kick drum or something... it goes "click" and shuts off. L.E.D is red again, and I got nothin. I can repeat it over and over.

Any ideas?

-Brandon

 

[highfigh]

Hey guys, i need some help figuring out what is wrong.

I came home today and put a cD in. I quickly realised that I wasn't getting anything out of my sub (eD a3-300). I thought maybe it got turned off. But, nope. Its plugged in turned on, but the l.e.d. light on the amp stays red. If i turn it off, turn it down the volume way low, and turn it back on, the L.E.D will be green and I will get music out of the sub... the as I turn it up, and get a little thump from a kick drum or something... it goes "click" and shuts off. L.E.D is red again, and I got nothin. I can do that over and over.

Any ideas?

-Brandon

Remove the woofer, disconnect the wires from the speaker and tape the ends so they can't short, then turn it on and start the source so the signal gets to the amp. If it still shuts off, it may have experienced a power surge or the power supply has a problem. If you have a multi-meter and can test the speaker for resistance, do that. If it shows 0 Ohms or OL (this means the voice coil is open), you have a bad speaker and it may have taken the amp with it. It's also possible that the amp went first and took the speaker out.

 

[Cpt.America]

highfive, thanks!

Ok, so I did all that you suggested, and the answer is "neither". I measured ohms across both voice coils, and it is 2.9 on each (I assume that is normal?). Then with the + and - wires taped, I turned the amp on... the LED stayed green... then I played music to the amp and could turn it all the way down or all the way up, and it stayed on the entire time. I attached a few pictures to make sure im measuring Ohms correctly, and to show the LED is in fact green while the volume knob is all the way up, while music is playing and LFE is going to the amp.

What's next?

 

[highfigh]

highfive, thanks!

Ok, so I did all that you suggested, and the answer is "neither". I measured ohms across both voice coils, and it is 2.9 on each (I assume that is normal?). Then with the + and - wires taped, I turned the amp on... the LED stayed green... then I played music to the amp and could turn it all the way down or all the way up, and it stayed on the entire time. I attached a few pictures to make sure im measuring Ohms correctly, and to show the LED is in fact green while the volume knob is all the way up, while music is playing and LFE is going to the amp.

What's next?

Put the jumper back on (It was connected from the negative post on the first coil to the second coil's positive, right?) and measure the resistance. It should double. If you get nothing, get another piece of wire for your jumper. If it is double, gently press on the cone and watch the meter to see if it shows 0 Ohms at any time. Again, listen for scraping, rubbing or clicking. If the reading looks good, connect it to the speaker wires from one channel of a receiver or other amp that you know is well protected from short circuits. If necessary, get an 8 Ohm wire wound resistor and connect that in series. The resistor will keep the amp from dying if the coil is shorted and if it works, you'll still hear the sound. If it works, listen closely to the sound quality.

 

[Cpt.America]

Put the jumper back on (It was connected from the negative post on the first coil to the second coil's positive, right?) and measure the resistance. It should double. If you get nothing, get another piece of wire for your jumper. If it is double, gently press on the cone and watch the meter to see if it shows 0 Ohms at any time. Again, listen for scraping, rubbing or clicking.

Yes, there was a jumper wire (see picture #1) . I put the jumper wire back on, and measured across from - on one to + on the other, and it reads exactly double. If I slowly press the cone in, it simply goes up.. 20, 30, etc. It only goes down if I let off the cone really fast, it jumps to like -50 as the cone is coming back out, then settles back down to 5.x.

Moving the cone in and out manually makes 0 noise of any kind. Very firm, very smooth... nada.

If the reading looks good, connect it to the speaker wires from one channel of a receiver or other amp that you know is well protected from short circuits. If necessary, get an 8 Ohm wire wound resistor and connect that in series. The resistor will keep the amp from dying if the coil is shorted and if it works, you'll still hear the sound. If it works, listen closely to the sound quality.

Well, I COULD run the speaker off the + - from a normal speaker channel on my Pioneer Elite, but I don't have a resister as a safeguard.. and Id hate to blow my receiver.... i dont really know what else to do.

 

[Cpt.America]

Ok, I just got off the "live chat" with Alex at eD, and we went over this thread, all the descriptions, all the pictures... and he thinks it's an issue with the protection circuitry in the amp, so I am going to send just the amp back, and they are going to hook me up with a replacement.

Quality customer service so far!

 

[highfigh]

Ok, I just got off the "live chat" with Alex at eD, and we went over this thread, all the descriptions, all the pictures... and he thinks it's an issue with the protection circuitry in the amp, so I am going to send just the amp back, and they are going to hook me up with a replacement.

Quality customer service so far!

Before you send it back, turn it on with the speaker disconnected and set the meter to DC Volts. If you measure more than about .1VDC, the amplifier has a definite problem or needs to be adjusted for DC offset, if that's part of the design. If you measure much more than this amount, the protection circuit should shut it down, as it has been.

 

[Cpt.America]

What am i measuring across? Do i need the LFE hooked up with music going?

 

[highfigh]

What am i measuring across? Do i need the LFE hooked up with music going?

You're just measuring from one speaker wire to another and the input can be connected, but the volume control needs to be all the way down.

 

[KEW]

Ok, I just got off the "live chat" with Alex at eD, and we went over this thread, all the descriptions, all the pictures... and he thinks it's an issue with the protection circuitry in the amp, so I am going to send just the amp back, and they are going to hook me up with a replacement.

Quality customer service so far!

It is nice that you're dealing with a company that lets you send back just a component. It is a pain when they make you ship the whole sub (especially if it is on your nickle).

 

[Cpt.America]

It is nice that you're dealing with a company that lets you send back just a component. It is a pain when they make you ship the whole sub (especially if it is on your nickle).

I had a similar experience with eD when I first bought the sub too. They called me on my phone the day it arrived to make sure it got there, that I liked it, that it worked, and that it made it there in one piece.

First and only time iv ever seen that.

 

[Cpt.America]

Before you send it back, turn it on with the speaker disconnected and set the meter to DC Volts. If you measure more than about .1VDC, the amplifier has a definite problem or needs to be adjusted for DC offset, if that's part of the design. If you measure much more than this amount, the protection circuit should shut it down, as it has been.

Well, I think I measured it right. From what I can tell, I measured .01 (not .1). But, I left the subamp volume knob all the way down like you said. Even when hooked up, it wasn't cutting out when it was turned down all the way... only as it was brought up and the sub started to move a bit.

 

[highfigh]

Well, I think I measured it right. From what I can tell, I measured .01 (not .1). But, I left the subamp volume knob all the way down like you said. Even when hooked up, it wasn't cutting out when it was turned down all the way... only as it was brought up and the sub started to move a bit.

Since no definitive speaker test has been done at this point, I think I would call them and ask if they want that back in addition to the amplifier. That way, you're not waiting for the amp to come back while they test it, when the possibility of a bad speaker still exists.

If you have access to a known good 4 Ohm woofer, try it with that connected and see if it still cuts out. If not, it would seem that the speaker is suspect.

 

[Cpt.America]

I do have another sub I can try... I can pull the alpine sub in a sealed box out of the trunk of my GF's car. I don't know if its 4 or 8 ohms.

 

[Cpt.America]

Since no definitive speaker test has been done at this point, I think I would call them and ask if they want that back in addition to the amplifier. That way, you're not waiting for the amp to come back while they test it, when the possibility of a bad speaker still exists.

If you have access to a known good 4 Ohm woofer, try it with that connected and see if it still cuts out. If not, it would seem that the speaker is suspect.

Highfigh... So i stole the sealed 10" alpine woofer out of the back of my GFs car... hooked it up to the + and - wires of the amp, ran the LFE back in, and fired it up.. and everything plays perfectly. It pushes that little 10" too full excursion with no trouble! It's gotta be the eD 12" sub?

 

[highfigh]

Highfigh... So i stole the sealed 10" alpine woofer out of the back of my GFs car... hooked it up to the + and - wires of the amp, ran the LFE back in, and fired it up.. and everything plays perfectly. It pushes that little 10" too full excursion with no trouble! It's gotta be the eD 12" sub?

Sure sounds like it- measure the car sub's DC resistance and if it's the same as (or close to) the eD, call them and tell them what you did. You never know- they may send a whole new sub. If they do, have them send a call tag so you aren't on the hook for shipping. You would be able to use the same box and slap the call tag right over the one they used.

 

[Cpt.America]

Sure sounds like it- measure the car sub's DC resistance and if it's the same as (or close to) the eD, call them and tell them what you did. You never know- they may send a whole new sub. If they do, have them send a call tag so you aren't on the hook for shipping. You would be able to use the same box and slap the call tag right over the one they used.

scratch that... still not workin

 

[Cpt.America]

Ok, So i put in a different CD that has a little more LFE.... the amp is screwed back into the eD enclosure.. but the wires are run out the hole for the sub and into the alpine sealed box, and its cutting out now like before playing through the other sub, but I have to turn it up a lot more before it kicks off. With the eD sub in the enclosure, it shuts off below 1/3rd power. So it's gotta be the amp... bah.. frustrating.

 

[highfigh]

Ok, So i put in a different CD that has a little more LFE.... the amp is screwed back into the eD enclosure.. but the wires are run out the hole for the sub and into the alpine sealed box, and its cutting out now like before playing through the other sub, but I have to turn it up a lot more before it kicks off. With the eD sub in the enclosure, it shuts off below 1/3rd power. So it's gotta be the amp... bah.. frustrating.

Did it play OK before you mounted it in the box? If it did and you're going to send it in, turn it on and see if you can make it go on and off by flexing the plate. If you can, it has at least one bad solder joint.