5 Channel Amp, Sub Channel Dead?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=145748
Printed Date: May 14, 2024 at 8:54 AM

Topic: 5 Channel Amp, Sub Channel Dead?

Posted By: frmdaleftcoast
Subject: 5 Channel Amp, Sub Channel Dead?
Date Posted: November 04, 2019 at 12:34 PM

This weekend my subs stopped hitting...no bass at all. Yet the speakers all work fine. Amp isn't in protect mode or anything like that. I used a DMM to check the ohms from the subs (1.5 ohms) and removed the subs to verify everything was good...which it is. Therefore my question is...what's most likely to be the issue - the head unit (JVC KWAV-71BT) or the amp?

JVC KWAV-71BT
JBL GTO939 (6x9/Front)
JBL GX963 (6x9/Rear)
American Bass SQ 3.5 (3.5"/Dash)
2 - 12" SoundQubed HDS3.1 (1,200w RMS ea.)
Hifonics BRX 5000.5 (5 channel amp)
Knuconceptz Wiring/SkyHigh (0 gauge, 4 gauge speaker wire, RCA, etc.)
Stinger 200 Amp Circuit Breaker
Stinger 100 Amp Circuit Breaker
Knuconceptz 300a InLine fuse
Kinetik HC600 - 600 Watt 12 Volt Power Cell Battery

PS - System was working fine for the last 6 months or so.

Replies:

Posted By: eguru
Date Posted: November 04, 2019 at 3:00 PM

If the other speakers are working, the HU is ok. So likely it is the Hifonics amp.

Posted By: frmdaleftcoast
Date Posted: November 04, 2019 at 3:42 PM

That was my 1st thought, but just now (during my lunch break) I used my DMM to check my RCA cables. I disconnected them from the amp and unit. I set the DMM to check continuity and tested on connection - received continuity between Pin/Pin & Outer Shell/Outer Shell (but it took awhile to finally get it). Tested the other RCA and received continuity from Pin/Pin, yet nada between Outer Shell/Outer Shell. So if I'm lucky, the issue will be my RCA cable.

Thanks for the reply!

Posted By: i am an idiot
Date Posted: November 05, 2019 at 3:57 PM

Connect the front or rear RCA into the sub input of the amplifier, does it play at all? Check every fuse on the amplifier.

Posted By: frmdaleftcoast
Date Posted: November 11, 2019 at 4:25 PM

UPDATE: After replacing the RCA, I still had the same problem. I set the amp to 3 channel mode (instead of 5) and it came back to life, but wasn't hitting nearly as hard as before. I replaced the HU w/Kenwood and - Problem solved. Therefore something went wrong in regards to the JVC HU and it's subwoofer connection.

Thanks to all those who responded!