# pop from basslink sub/amp



## splat (Dec 14, 2008)

i got an infinity basslink powered sub and installed it yesterday in a 2002 honda civic lx sedan. When i hooked it up to my Aiwa CDC-X504mp head unit, I would get "thumps" from the sub when I changed tracks on the cd and when I changed the eq settings, also when the car turned off. I do not get thumps when the car turns on. I have rechecked the ground to the sub and the head unit. I reran the amp power line from the head unit. I disconnected the RCA lines from the headunit and connected an ipod directly to the sub. When I had the ipod connected there were no pops or thumps.

another mysterious symptom is that the sub remains on after the car is turned off and the servo led stays lit solid when the rca cables from the head unit are still connected. if i disconnect the rca cables then the sub turns off correctly. I have the "auto on" switch set to off. If i plug the rca cables in while the car and sub are off, the sub will turn on and when both cables are connected the servo led will then light up.

i even went out and bought a new head unit to test if the problem was the aiwa or not, but the "thumps" are still there with the new head unit.

this morning I tried 3 different ground locations, sanding down the paint first at each location, and the symptoms were the same whether the ground was connected to a point or not.


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## Jimi77 (Jul 4, 2005)

splat said:


> another mysterious symptom is that the sub remains on after the car is turned off and the servo led stays lit solid when the rca cables from the head unit are still connected. if i disconnect the rca cables then the sub turns off correctly. I have the "auto on" switch set to off. If i plug the rca cables in while the car and sub are off, the sub will turn on and when both cables are connected the servo led will then light up.
> 
> i even went out and bought a new head unit to test if the problem was the aiwa or not, but the "thumps" are still there with the new head unit.
> 
> this morning I tried 3 different ground locations, sanding down the paint first at each location, and the symptoms were the same whether the ground was connected to a point or not.


Have you tried the auto on position? What happens?


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## splat (Dec 14, 2008)

the "auto-on" switch is supposed to be for speaker level inputs, not RCA + Amp Remote. But yes, i've tried turning "auto on" to on, it doesn't change anything.


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## 14642 (May 19, 2008)

sounds like some significant DC offset on the RCA outputs of the head unit.


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## splat (Dec 14, 2008)

so how would i get rid of that? i've tried regrounding the head unit to two different bolts too, as well as the original wiring harness.


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## splat (Dec 14, 2008)

bump. anyone?


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## Jimi77 (Jul 4, 2005)

Well it looks like you've eliminated the HU as the source of the problem. I would make sure you don't have 12v+ constant at the remote in on the basslink. The basslink should be shutting off.


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## splat (Dec 14, 2008)

if i unplug the RCA lines from the head unit, it turns off. If i hook up an MP3 player directly to the amp/sub with RCAs instead of the head unit, the sub/amp acts "as it should" in that I will need to turn the car on to turn the sub on and I get no pops or thumps. The only thing I haven't done yet is instead of hooking the head unit up to the RCA cables, hook the MP3 player up to the same RCA cable. I was using a 1/8" male to RCA male cable before and I haven't gotten my hands on a 1/8" to RCA female adapter yet, but that is my next move right now.


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## splat (Dec 14, 2008)

i love when you finally figure out what is causing a problem and you feel like a huge idiot for not checking it before...the RCA line was pinched under one of the trim panels.


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## splat (Dec 14, 2008)

woops, false alarm. so at lunch today i thought I figured it all out but I didn't go 100% because of time. So with the wire still run in it's original location, I connected an mp3 player using a rca-to-1/8 adapter directly to the RCA cable which was connected to the amp/sub. with the cable in it's original location, this made the sub turn on and the servo light up....which is the exact same thing that was happening before. So i pulled the entire rca cable out and checked it. All of the outside was still intact but you could easily see where it had been pinched, but nothing had broken. I then plugged the mp3 player in again (with the rca line not running behind any panels, etc.) and the sub/amp worked perfectly. So i thought i figured it out.

just now, i decided to rerun the RCA, taking care not to pinch it. As soon as i plug it in to the head unit i get the old problem...powers on and servo lights up. So i took the rca out from behind all of the panels and just ran it straight to the head unit, not hiding it at all....same thing.

so once again, I have no idea.


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## mpls|cafe|racer (Jan 13, 2009)

I want to get a basslink. Is there only one model?


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## splat (Dec 14, 2008)

no, there's two - the old one that is 200w, which i have, and the new one that is 250w, which is called the Basslink II.


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## Jimi77 (Jul 4, 2005)

splat said:


> i love when you finally figure out what is causing a problem and you feel like a huge idiot for not checking it before...the RCA line was pinched under one of the trim panels.



Interesting. And that caused the Basslink to stay on...


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## rdv (May 14, 2007)

not sure if you mentioned it but did you try using another rca? i wasnt clear if that's what you tried with the mp3 player. it may have been damaged internally when it was pinched?


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## Rudeboy (Oct 16, 2005)

Sounds like it's time to contact Infinity.


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## splat (Dec 14, 2008)

i haven't tried a brand new RCA from the head unit to the amp/sub yet. I used the exact same RCA from mp3 player to the amp/sub and it worked fine. I'm going to try a completely different rca cable tonight if I can find one long enough, otherwise I might need to rig something up.

i'm trying to think how I can swap out the sub to test and see if that is the culprit, I don't know anyone locally who has a sub i can swap with so I might have to buy a new one from a place with a good return policy.


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## splat (Dec 14, 2008)

dup, sorry***


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## splat (Dec 14, 2008)

new RCA cable didn't fix it, so i guess my next step is to find some one to swap sub/amps with so I can see if it's a problem with the car itself or the basslink


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## Rudeboy (Oct 16, 2005)

splat said:


> if i unplug the RCA lines from the head unit, it turns off. If i hook up an MP3 player directly to the amp/sub with RCAs instead of the head unit, the sub/amp acts "as it should" in that I will need to turn the car on to turn the sub on and I get no pops or thumps. The only thing I haven't done yet is instead of hooking the head unit up to the RCA cables, hook the MP3 player up to the same RCA cable. I was using a 1/8" male to RCA male cable before and I haven't gotten my hands on a 1/8" to RCA female adapter yet, but that is my next move right now.


Turning the car on shouldn't send power to the amp - it should only power up when the head unit is turned on - that's what the remote wire is for. What happens when you disconnect the remote wire from the amp?


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## splat (Dec 14, 2008)

if i run the RCAs from the head unit to the basslink, it will turn on and the servo will light up even if the remote power line is disconnected and even the car is turned off. If the remote power line is disconnected and I attach an mp3 player, the basslink does not turn on. Since the basslink works as it should when i have the mp3 player connected, doesn't that mean it isn't the basslink that is bad? the problem only presents itself when an rca cable is connected between the basslink and the head unit....even if the ground is disconnected and even if the remote power is disconnected.


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## 2167 (Dec 5, 2007)

"I reran the amp power line from the head unit"
I have a question about this statement in your first post.
Are you getting power for the sub from the radio main power?
If so that is a NO NO, power should be run directly from the battery (with a fuse in the first 18 inches).


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## vidizzle (May 30, 2008)

try another hu in the car and/or another amp just to make elimination of problems easier


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## Rudeboy (Oct 16, 2005)

2167 said:


> "I reran the amp power line from the head unit"
> I have a question about this statement in your first post.
> Are you getting power for the sub from the radio main power?
> If so that is a NO NO, power should be run directly from the battery (with a fuse in the first 18 inches).


Good point. Are you running power directly from the battery to the Basslink? When the MP3 player is connected does turning the HU on turn on the Basslink and turning the HU off turn the Basslink off?


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## splat (Dec 14, 2008)

2167 said:


> "I reran the amp power line from the head unit"
> I have a question about this statement in your first post.
> Are you getting power for the sub from the radio main power?
> If so that is a NO NO, power should be run directly from the battery (with a fuse in the first 18 inches).


I'm using a scosche wiring kit: EFX 10-gauge Amplifier Wiring Kit Power and signal connections for your new amp at Crutchfield.com I have the power running straight from the bettery, thru the firewall and down the passenger side of the car. I have the remote power running from the blue with white stripe line (per the aiwa manual) and I have that running down the passenger side of the car too. I double checked those lines last night to make sure they weren't pinched. That wiring kit comes with a 30amp fuse, but the basslink calls for a 20amp, so I replaced the fuse in the battery power line with a 20amp.

I had the RCA cable running down the drivers side to keep it away from the power lines.



vidizzle said:


> try another hu in the car and/or another amp just to make elimination of problems easier


already tried another HU, it was a pioneer 4000UB, and it had the same problem.



Rudeboy said:


> Good point. Are you running power directly from the battery to the Basslink? When the MP3 player is connected does turning the HU on turn on the Basslink and turning the HU off turn the Basslink off?


with an mp3 connected to the RCAs, the basslink works as it should, i.e. i get no pops/thumps, the power light and servo light don't come on when the RCA is connected, when i turn the car on, the basslink turns on when the head unit turns on, when i turn the car off the basslink turns off.


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## Rudeboy (Oct 16, 2005)

splat said:


> with an mp3 connected to the RCAs, the basslink works as it should, i.e. i get no pops/thumps, the power light and servo light don't come on when the RCA is connected, when i turn the car on, the basslink turns on when the head unit turns on, when i turn the car off the basslink turns off.


Have to clarify this when MPS player connected. Car on to get power to the HU. HU turned on - Bassilnk turns on. HU turned off - Basslink turns off. Confirm.

Also, the servo light should only come on during heavy bass passages at high volume to indicate that you're near the limit. Confirm. How many RCA's are you running from the HU to the Basslink?


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## splat (Dec 14, 2008)

Rudeboy said:


> Have to clarify this when MPS player connected. Car on to get power to the HU. HU turned on - Bassilnk turns on. HU turned off - Basslink turns off. Confirm.


correct.



> Also, the servo light should only come on during heavy bass passages at high volume to indicate that you're near the limit. Confirm. How many RCA's are you running from the HU to the Basslink?


1 set of RCAs. This is the problem and I believe the cause of the thumps. Somehow when I connect the RCAs to the basslink and the headunit, the amp is getting overloaded, then the thumps are the discharge of the extra charge built up in the amp. I can't find where this extra charge is coming from tho.


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## Rudeboy (Oct 16, 2005)

splat said:


> correct.
> 
> 
> 
> 1 set of RCAs. This is the problem and I believe the cause of the thumps. Somehow when I connect the RCAs to the basslink and the headunit, the amp is getting overloaded, then the thumps are the discharge of the extra charge built up in the amp. I can't find where this extra charge is coming from tho.


Where do you have the gain control set? The owner's manual has instructions for connecting speaker level inputs when you only have 2 RCA's to connect. Have you done this? It shouldn't be necessary to get the thing functioning properly, but a problem there might account for it powering up without a remote wire attached.


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## splat (Dec 14, 2008)

i have the gain, crossover, and bassboost set to half way since I haven't been able to do true tuning yet. I don't have the "sub level control" connected since my head unit can control sub level. The speaker-level connection is just required there is no remote turn-on line, that way you can set the amp to auto turn on when it senses signal over the speaker lines. It cannot detect signal over the RCAs, so you need the remote power line OR the speaker lines....not both. But, if I have this confused definitely correct me. I have read this manual several times tho so I am fairly certain I am correct.


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## Rudeboy (Oct 16, 2005)

splat said:


> i have the gain, crossover, and bassboost set to half way since I haven't been able to do true tuning yet. I don't have the "sub level control" connected since my head unit can control sub level. The speaker-level connection is just required there is no remote turn-on line, that way you can set the amp to auto turn on when it senses signal over the speaker lines. It cannot detect signal over the RCAs, so you need the remote power line OR the speaker lines....not both. But, if I have this confused definitely correct me. I have read this manual several times tho so I am fairly certain I am correct.


As long as you don't have any speaker level connections made, we can rule that out as an issue. *Now that you have switched to a Pioneer HU, you have to be very careful about about connecting and disconnecting RCA's with the power connected. They are very fragile in this regard and you really need to disconnect the negative battery terminal before you do anything with the HU RCA's*

Do you have a DMM? It seems that the only possibility other than a defective Basslink is something screwy with the RCA's. A good start, with the RCA's disconnected from the HU would be to test for shorts, but since you've said you're using the same set of RCA's with the MP3 player, that shouldn't be it either. That leaves the signal coming through the RCA's. If you have a DMM, compare the voltage produced by the MP3 Player and the HU. An easier but maybe riskier approach (I take no responsibility for the outcome, but I've done it myself) is to put on some headphones and do this:








You should hear whatever is playing faintly but clearly in one ear. I'd keep the volume very low at the HU to start and maybe use a set of headphones that you consider disposable - just in case there is some nasty stuff coming through.


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## splat (Dec 14, 2008)

i returned the pioneer head unit since it didn't fix the problem, so i'm back on the aiwa cdc-x504mp. every time i've been making connections directly to the HU i've been disconnecting the battery first. I do have a multimeter so I'll test the voltages coming thru on the RCAs tonight or tomorrow, when i can find some time.


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## Rudeboy (Oct 16, 2005)

Also try the RCA's from the HU one at a time at the amp.


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## splat (Dec 14, 2008)

Rudeboy said:


> Also try the RCA's from the HU one at a time at the amp.


i gotta plead ignorance on that one...how could I not have only one HU hooked up at one time?


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## Rudeboy (Oct 16, 2005)

splat said:


> i gotta plead ignorance on that one...how could I not have only one HU hooked up at one time?


You have two RCA's running from the HU to the Basslink. Instead of plugging both into the Basslink at the same time, try them on at a time.


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## splat (Dec 14, 2008)

the aiwa only has one rca output which can be set to "sub" or "rear". i have it set for sub. when i plug in one channel (left or right), the sub turns on. when i plug in the 2nd channel, the servo light turns on.

i didn't have any time tonight to do more testing, i'll try to do some more tomorrow.


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## splat (Dec 14, 2008)

the aiwa only has one rca output which can be set to "sub" or "rear". i have it set for sub. when i plug in one channel (left or right), the sub turns on. when i plug in the 2nd channel, the servo light turns on.

i didn't have any time tonight to do more testing, i'll try to do some more tomorrow.


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## Rudeboy (Oct 16, 2005)

splat said:


> the aiwa only has one rca output which can be set to "sub" or "rear". i have it set for sub. when i plug in one channel (left or right), the sub turns on. when i plug in the 2nd channel, the servo light turns on.
> 
> i didn't have any time tonight to do more testing, i'll try to do some more tomorrow.


Try it with the output set to "rear".


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## splat (Dec 14, 2008)

i'll give that a shot, but the basslink still shows the symptoms (power light, servo light) when the car is still turned off.


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## Rudeboy (Oct 16, 2005)

splat said:


> i'll give that a shot, but the basslink still shows the symptoms (power light, servo light) when the car is still turned off.


Is it possible that something strange is going on behind the HU when the RCA's are plugged in? Have you tried it with the HU out of the dash? Something truly funky is being sent up those RCA's if just connecting them to the amp with the car turned off is sending it power. Something is overwhelming the Basslink's desire NOT to monitor the low level inputs for signal or power. With the car turned off, there should be nothing on the RCA's at the amp end. That should be your first DMM test - turn the car off and see what you're getting at the RCA's unplugged from the amp. If one of them is showing 12 VDC, you'll have a very good clue.


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## Jtejedor (Dec 19, 2008)

Are you running a remote wire from your headunit to the basslink? I had one a long long time ago and I seem to remember I might have had this same problem. If it really bugs you maybe wire a relay to delay turn on. Could it just be an issue with the amp on the basslink?


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## splat (Dec 14, 2008)

so very odd, i measure 0 volts at the RCAs on the back of the head unit, but I still get sound of out of basslink when the hu is hooked up to it. and it flashes the - on the screen, sort of like if I were to just touch the + and - leads together, which makes it seem very fishy to me.

my mp3 player produces 1.33v, even when it's turned off (seemed odd to me that it would do that). I'm getting 12.33v across the battery+ and ground leads on the basslink so I think those are hooked up fine (also tested between a random bolt in the trunk, same voltage).

I'm getting pretty fed up with this so i think i may just call best buy up and see if I can have some one help troubleshoot....hopefully get this figured out quickly.


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## Rudeboy (Oct 16, 2005)

Any further developments?


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## splat (Dec 14, 2008)

over the weekend I did get it in to BestBuy for one of their guys to look everything over. After 2 hours of troubleshooting, he finally found another amp to throw in and hook up to my wiring and it worked perfectly, so our conclusion is that the basslink is at fault. I ordered a new one that will hopefully be here tomorrow so I'm hoping the new one will not have the same problem. If it does have the same problem, i guess I'll go to a regular amp+sub+box solution but I'd rather not take up that space in the trunk.


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## splat (Dec 14, 2008)

whelp. new basslink arrived today and it works perfectly fine. I'm glad it's solved now, but i'm still frustrated it took so long to figure that out.


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## Rudeboy (Oct 16, 2005)

splat said:


> whelp. new basslink arrived today and it works perfectly fine. I'm glad it's solved now, but i'm still frustrated it took so long to figure that out.


That's why I suggested you contact Infinity a week ago


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## splat (Dec 14, 2008)

it just made no sense how it worked fine when attached to an outside input. it worked fine when attached to the testbench at bestbuy too. I guess it was just something with the closed system of the car. i guess i'm over thinking it since i'm an engineer...no need to worry about it now.


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## Rudeboy (Oct 16, 2005)

Glad it worked out.


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## MarcelKer (Feb 15, 2009)

Hi Guys,

Sorry for my bad language. I'm from the netherlands ( europe ).

Having exactly same problem over here.
Also going well when pulling the RCA's out of the basslink.
When connected also POP's every time I switch source, or just switch track on playing a CD.

Having troubles with the shop were I bought it. They say I need to re-run al the wires but
also tried another RCA kabel just running over my chears connected with outhanging HU.

I'm a little frustrated because of my shop will not replace my device.

Any ideas?

Thanks already!


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## adaycj (Oct 25, 2008)

If you do some searching on the Internet you will find that Infinity has had significant problems with the Basslink II version that replaced the original one. Lots of bad boards and early life cycle failures.


Call Infinity and hopefully they will stand behind their product.


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## jopet (Jun 22, 2009)

Hi there. I was reading your posts and I do have the same problem with my basslink. It is only 6 weeks since I initially installed it. My problem is the same. A loud thump when changing the source of the head unit also when turned off. The power light is still on even though the HU is off. I found that pulling out the RCA turns the light off. The unit is grounded. There is a negative current coming from the RCAs that is the source of power for the light. The amp is not really on. I know this because I connected another RCA to Basslink and rubbed the other end on a bare metal part of the car. Yes the light turns on as well. I think I found the solution, at least for me. I had a water melon in the trunk before this happened. I think the fruit crashed in the sub and damage somewhat one of the knobs. In this case, the gain knob. I tried pulling the knob - viola!!! the light goes away. But it seems that the knob pulls back and the light comes back. When this light is on, the thumps are present, without the light, alls well. I will be working on this with my brother this weekend. We will try to open the unit. We think that the knob circuit board is touching the RCA board. I'll post our finding ASAP


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## awgray (Apr 4, 2007)

My guess is that the auto-turn on sensitivity is to blame...I've had this problem with subwoofer plate amps before. The amp is "sensing" a signal despite there not being one present and the internal cicuitry tells the amp to turn on.

Try the following link:

PE Sub Amp Auto Bypass - Home Theater Forum

Oh and by "try" I mean, this could be the problem and is not intended to be the solution.


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## jopet (Jun 22, 2009)

got to go home early yesterday and was not able to wait for the weekend. I opened up my basslink - bottom line - its working fine now. 2 circuit boards are back to back to each other about 2mm away. It's not impossilble for the circuitry to be grounding each other. One board is actually installed leaning to one side to try to avoid the other board. A lot of problems could have been avoided if one of the those boards where position just a bit more further. The problem with my basslink was that the flat cable that connects the knob circuit board to the main board did not have a terminal at one end. It looked like it was glued on and there was an exposed wire (or element). I just wrapped it with electrical tape. put the thing back together and installed it back in the trunk of my car. Now its working fine. I will continue to observe it though. Oh yeah, I should have taken pics to show everyone - sorry


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## jopet (Jun 22, 2009)

more than a month after the fix, still booming!


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