RCA voltage low, subs no longer work, and ohm load is 300+ and climbs, HELP!

[MrAcd 10+ year member]

Okay so to start off, I had everything working perfectly fine up until i had to remove my box and subs so i could paint the box. I was having bass withdrawals from two weeks and i needed to hear some bass. By this time the box has been painted and now only needs a clear coat. I thought "ehh it will be okay to just install it without a clear coat for now, it isnt like the box is going anywhere" I went and hooked everything up just like i had it before, and when i went to play some music, the subs didnt move at all.

I pulled out the DMM and measures AC volts going to the subs.....0. So i was thinking that was weird that the subs where not getting power. (btw the amp is on and is getting good voltage.) I checked my final ohm load thinking i wired it wrong.The DMM read 323.... and the crazy part was it was climbing every second. at least 1.5 ohms a second.

I went back checked the wiring, and it was all done correctly, i even re wired some parts. Get this, with the car off i get my 2 ohm load. As soon as the amp/radio turns on the ohm load goes back to the 3xx and starts climbing. I wasnt sure what was going on or why i wasn't getting any amplified signals out. Thinking something is wrong with the input signal, because maybe the amp wasn't receiving any signal to amplify.

I went to the RCA's and checked their input level with a 55hz test tone, not at max volume but at reasonable loud volume. I got a reading of .5mv. Now thinking that my RCA may have come loose during the 2 week period, i pulled my HU out and they where fine. As im typing this I just thought about grabbing a RCA to 3.5mm jack and hook it up to the amp and playing something off my phone to see what the results where. I will do that tomorrow, at least that will get rid of the option that the HU or RCA's are bad.

I tried to give the whole run down of the situation so we know all aspects, usually i could solve these problems myself but this one i dont have a clue. Something also to mention when i unplugged the speaker wire for two weeks i did not unplug it from the amp, so i did have live wire on the floor of my truck... bad move on my part. Some other testing i did was plug the a single sub the amp, and same results. power off = 4 ohm, power on= 300+ohms.

If you need more information tell me, or if you could help me out in any way to solve this, that would be great

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[MrAcd 10+ year member]

So i re tested my voltage at the RCA's and to find out, with like a 70hz test tone with HU at 43/62 i was getting 1.1v, so i think that my RCA's are fine, it has to be the amp, that is what im thinking. Can anybody help me out?

 

[Jeffdachef 5,000+ posts]

you are on the right track. Do the 3.5 mm to rca test.

Check each subwoofer's coil to see if they are still good.

At any point did you accidentally have the speaker leads pos and negative touch?

 

[MrAcd 10+ year member]

Coils are all good on both subs, just checked the 3x 40 amp fuses on the amp and they are good. About to go do the 3.5 to RCA test.

I am scared that the speakers leads did touch at some point..... I dont know for sure, since they where in the rear.

I couldn't find anything at all about ohm'c continuing to rise only when power is received. Even at the amp with the power off the amp sees the correct ohm's, as soon as the amp is powered on, the ohm's jump from 2.2 ohms to 314 and then climb.

 

[MrAcd 10+ year member]

Just did the 3.5 to RCA test, same results, so this is an amp issue, or electrical. Any recommendations on where to start looking now?

BTW, just to make sure, what i did was plug up my phone and play a song with it hooked up through the RCA to 3.5mm cord and looked for any VAC with my DMM at the speaker outputs, and i got nothing.

 

[los33 10+ year member]

Just did the 3.5 to RCA test, same results, so this is an amp issue, or electrical. Any recommendations on where to start looking now?
BTW, just to make sure, what i did was plug up my phone and play a song with it hooked up through the RCA to 3.5mm cord and looked for any VAC with my DMM at the speaker outputs, and i got nothing.

Electrical wont cause ohm to rise.

A malfunctioning amp will.

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[MrAcd 10+ year member]

Electrical wont cause ohm to rise.
A malfunctioning amp will.

Sent from my draconis using Tapatalk

darn... thats not good news at all. any way i can confirm this? Like if i crack it open, is there anything i can look for?

Could a bad ground cause any of this?

 

[los33 10+ year member]

darn... thats not good news at all. any way i can confirm this? Like if i crack it open, is there anything i can look for?
Could a bad ground cause any of this?

I cannot offer any help towards this, but maybe contacting someone with better knowledge towards finding problems on amps.

Only thing i can suggest is swap the amp out with a friends or swap and older headunit in to test if it is not the headunit having rca issues.

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[poolman966554]

if you changed rca input devices and have same result, most likely the amp is bad. as you mentioned, id double check all connections first.

 

[MrAcd 10+ year member]

I cannot offer any help towards this, but maybe contacting someone with better knowledge towards finding problems on amps.
Only thing i can suggest is swap the amp out with a friends or swap and older headunit in to test if it is not the headunit having rca issues.

Sent from my draconis using Tapatalk

alright, well maybe somebody else can comment, thanks for the help.

I am almost sure it isnt a RCA issue being the test i have done so far.

 

[poolman966554]

you could simply try another amp as loss suggested. also, take the cover off you amp, you might see why its not working properly