Sub will only work if I have 1 RCA cable plugged in.

[Lawjic]

Total newbie here... Seeking answers. Tried searching google with no real results.

I called Crutchfield and they suspected a bad amp, and replaced it, but same issue exists on new amp.

If both RCA cables are plugged in, I get no sound from my sub. If I unplug one of the RCA cables, the sub comes to life. Doesn't matter which I unplug. I can unplug either one and the sub works, but for some reason, with both plugged in I get nothing.

I tried a different amp (as stated), and different sub itself. I had two 6.5" subs in my rear deck I tried first, no luck there. Bought a loaded sub off amazon, still the same issue...

Has anyone experienced anything like this before? Any suggestions on next steps? I was thinking of maybe trying new RCA cables, but that's about all I got at this point...

For reference, the head-unit is a ILX-W650. I have a KTA-450 amp connected to it for the door speakers, and I use a S2-A60M amp for the sub. Speakers are working fine at all times, only issue I have is with the sub...

The two 6.5 rear deck subs are little skar subs, and the loaded sub is a 10" skar sub.

Thanks for your insight!

Mac

Click to read more...

 

[1aespinoza 10+ year member]

Thanks for your insight!

It sounds like a polarity issue. Try switching polarity on one of the subs and test it.

 

[some dude]

Can you post a pic of the connections?

 

[Lawjic]

Can you post a pic of the connections?

Attaching a few pics in my Google drive here: https://drive.google.com/drive/folders/1thT5Qck7nKTL2Bkx0_ph9vI9W3e4R4P_

For simplicity I hooked up my single sub to rule out any writing mistakes I may have done with the 2 6.5 inch subs

It sounds like a polarity issue. Try switching polarity on one of the subs and test it.

I tried switching the rca cables, and from my head unit, there's an option to switch 180, neither helped unfortunately

 

[spokey9]

Have you tried different rca cables?

 

[SlugButter]

When you switched the rca cables around on the head unit, did the same one not work? You can determine if it’s at the head unit or the amp by checking that. If the same side of the cable doesn’t work no matter how it’s switched around, it’s likely a bad cable,

 

[Lawjic]

Have you tried different rca cables?

I haven't yet, but I did order another set to test.

When you switched the rca cables around, did the same one not work? You can determine if it’s at the head unit or the amp by checking that. If the same side of the cable doesn’t work no matter how it’s switched around, it’s likely a bad cable,

So, it only works if only one RCA cable is plugged in. Doesn't matter which one. I can leave white plugged in, red unplugged, and it works. Leave red plugged in and white unplugged, works. Both plugged in, no dice

 

[audiobaun 5,000+ posts]

I had the same issue with a Bnew Sony HU about 4 years ago. I was using one of my Autotek BTS 7300s @ 2 ohms on a pair of 600rms 10s, I kept having the same issue, swapping RCAs tried another 7300 I had,another amp. and finally gave up. I even went through the HU several times to try to see if it was something in settings?I even tried a Hard RESET and even pulled power for 2 days. I never found the issue, so I pulled that HU and put one my old Trusties back in and worked fine.? I even went through all the amplifiers again, and they were fine. I suspect its the HU RCA Out.. I boxed that HU up and its still boxed up. I never cracked it open though. Bought another Kenwood, 4v-6 RCA out and never had an issue

 

[Lawjic]

I had the same issue with a Bnew Sony HU about 4 years ago. I was using one of my Autotek BTS 7300s @ 2 ohms on a pair of 600rms 10s, I kept having the same issue, swapping RCAs tried another 7300 I had,another amp. and finally gave up. I even went through the HU several times to try to see if it was something in settings?I even tried a Hard RESET and even pulled power for 2 days. I never found the issue, so I pulled that HU and put one my old Trusties back in and worked fine.? I even went through all the amplifiers again, and they were fine. I suspect its the HU RCA Out.. I boxed that HU up and its still boxed up. I never cracked it open though. Bought another Kenwood, 4v-6 RCA out and never had an issue

Oh man, I hope it's not the head unit... Would there be any risk to running it off one RCA cable permanently? Seems like decent sound coming from it... Just don't know if it would cause any issues long term..?

 

[audiobaun 5,000+ posts]

Total newbie here... Seeking answers. Tried searching google with no real results.

I called Crutchfield and they suspected a bad amp, and replaced it, but same issue exists on new amp.

If both RCA cables are plugged in, I get no sound from my sub. If I unplug one of the RCA cables, the sub comes to life. Doesn't matter which I unplug. I can unplug either one and the sub works, but for some reason, with both plugged in I get nothing.

I tried a different amp (as stated), and different sub itself. I had two 6.5" subs in my rear deck I tried first, no luck there. Bought a loaded sub off amazon, still the same issue...

Has anyone experienced anything like this before? Any suggestions on next steps? I was thinking of maybe trying new RCA cables, but that's about all I got at this point...

For reference, the head-unit is a ILX-W650. I have a KTA-450 amp connected to it for the door speakers, and I use a S2-A60M amp for the sub. Speakers are working fine at all times, only issue I have is with the sub...

The two 6.5 rear deck subs are little skar subs, and the loaded sub is a 10" skar sub.

Thanks for your insight!

Mac

What Brand of amp is that on sub duty?? There are quite a few new Mono amps that will take only 1 rca In . From HU L+R(White +Red) to 1 RCA In on Mono amplifier. Then on mono amp you may have (L+R/White and Red) OUT to use signal for another external amp or even to Slave from Master

 

[Lawjic]

What Brand of amp is that on sub duty?? There are quite a few new Mono amps that will take only 1 rca In . From HU L+R(White +Red) to 1 RCA In on Mono amplifier. Then on mono amp you may have (L+R/White and Red) OUT to use signal for another external amp or even to Slave from Master

The sub amp is an alpine S2-A60M

 

[audiobaun 5,000+ posts]

Oh man, I hope it's not the head unit... Would there be any risk to running it off one RCA cable permanently? Seems like decent sound coming from it... Just don't know if it would cause any issues long term..?

It should be alright. /Fine. Its just a signal. You can buy a Y adapter and try to split to the 2 ch from the single RCA from the HU. Dont expect 4v from the HU to the Amp if thats what the hu puts out per RCA Ch.Expect 1/2. I would atm tape up the exposed RCA for now. But I would look into another HU if the amp you have isnt a single RCA Mono amp RCA Input. The HU was My culprit after a two week find after work and on weekends

 

[audiobaun 5,000+ posts]

The sub amp is an alpine S2-A60M

Did you buy this amp BNEW? how about your HU? New or used or came used in the Vehicle. Ill look that amp up. Alpine still make some dammned good amps

 

[Lawjic]

Did you buy this amp BNEW? how about your HU? New or used or came used in the Vehicle. Ill look that amp up. Alpine still make some dammned good amps

All new equipment from crutchfield. Head unit I've had a couple years, and just now getting around to add an amp and sub.

I had an S-A60M I bought about 2 months ago. Crutchfield suspected a bad amp when I asked them, so they sent me the S2-A60M which is apparently the newer version of the amp I bought. Same issue on both.

I do see it says mono amp, I assumed that meant one ourput like a sub. Does that actually mean mono in too, even though there is red and blue RCA jacks?

Should I get the Y splitter and connect 2 ends at head unit, then the y splitter and 1 connection at the amp?

 

[audiobaun 5,000+ posts]

The sub amp is an alpine S2-A60M

Thats a nice amp man. Make sure you have the switch set to LO on the Input level and use the RCAs directly to the right of that switch that says INPUT White on top/Left and the Red on bottom to Right, should be same from the HU is common practice. MAKE SURE You turn your Gain down to about 9-Oclock position or lower if you did not place the Input level switch on LO, and make sure your Volume Knob on the HU is down to a low listening level also so you dont clip or blow a sub.. LOL