csshakka Posted August 15, 2014 Report Posted August 15, 2014 My friend has a weird issue with his Alpine MRX-M240. He recently got a new car and due to the cool/funky dash shape, opted for a line-out converter (he chose an active one). However, after a few minutes of playing, the sub just cuts out. Testing AC voltage on the RCA input shows it drop to 0v after this happens. The amp stays on. The signal coming from the same LOC going to the full-range amp stays on and plays perfectly. If you turn the car off/on the sub will play again for a few min before cutting out. It happens at any volume, but the louder the volume, the quicker it cuts out (usually). He's only running the amp at 4 ohms (1500 watts x 1) on an American Bass XFL D2. This same equipment was ran for a year in his old car no problem. We also tested his amp and sub in my car, running off of my 80prs opposed to an LOC and it worked perfect and never cut out. This initially led to the LOC being bad. He took it to a nearby shop and tested two different model LOC's (these ones passive), but the same thing happened. After reinstalling the original LOC, we tested a different sub amp and it did NOT cut out. For some reason his Alpine MRX-M240 does not like LOCs. We also monitored voltage - it's definitely not an issue. Also, all fuses were replaced and wires re-secured in all of fuse holders, etc. The ground is on sanded down bare metal - the same area that the full range amp ground is mounted to with no problems. Anyone have any ideas or heard of this before?
SIDE SHOW Posted August 15, 2014 Report Posted August 15, 2014 does it still cut out when the gain on the amp is turned all the way down? pics
csshakka Posted August 15, 2014 Author Report Posted August 15, 2014 does it still cut out when the gain on the amp is turned all the way down? pics Not sure if we tried this. Pics of what? If it doesn't cut out with gain all the way down, what would that tell us?
SIDE SHOW Posted August 15, 2014 Report Posted August 15, 2014 pics of the loc and amp your using...... if it doesn't cut out with the gain all the way down, your either trying to get too much out of that amp or the electrical isn't upto par. cant be a problem with the amp coz it works in your car, so either signal,gain or electrical issue id say
csshakka Posted August 15, 2014 Author Report Posted August 15, 2014 pics of the loc and amp your using...... if it doesn't cut out with the gain all the way down, your either trying to get too much out of that amp or the electrical isn't upto par. cant be a problem with the amp coz it works in your car, so either signal,gain or electrical issue id say I'll ask him what LOC is in. This is the amp: http://www.alpine-usa.com/product/view/mrx-m240/default His amp is in flawless condition - not even a scratch on it. I would say electrical issue is ruled out too. A different amp was tested in there with the LOC putting out the same power with no problem. Gain was set with DD-1 and clearly not distorting, even playing at higher volume. It just doesn't make sense why the signal cuts out when using the alpine amp, but not another amp and that the alpine amp works with an aftermarket head unit. Is it an issue with ford stock head units possibly?
SIDE SHOW Posted August 15, 2014 Report Posted August 15, 2014 bass boost and everything is off, have just noticed that amp has speaker level inputs. have you tried using them instead of the loc? the amp might not be getting a strong enough signal from the loc. input sensitivity rca input = 0.1v to 4v input sensitivity speaker level input = 0.5v to 10v how is the sub wired also? its a duel 2 ohm sub... have you checked the sub ? take the fuse out in the amp and re-fit it. make sure it's not dodgy
deathcards Posted August 15, 2014 Report Posted August 15, 2014 maybe the remote sensing it having problems with the loc skar sk2500.1 0 gauge power and ground kunukonceptz alpine HUvxi65 components on BA gt-275new build log -> http://www.stevemeadedesigns.com/board/topic/150642-project-d-kon-deathcards-build-log/#entry2148821 2 x-15 sundowns singer alt, odyssey bat, and maxwell ultra caps
csshakka Posted August 15, 2014 Author Report Posted August 15, 2014 bass boost and everything is off, have just noticed that amp has speaker level inputs. have you tried using them instead of the loc? the amp might not be getting a strong enough signal from the loc. input sensitivity rca input = 0.1v to 4v input sensitivity speaker level input = 0.5v to 10v how is the sub wired also? its a duel 2 ohm sub... have you checked the sub ? take the fuse out in the amp and re-fit it. make sure it's not dodgy Oohhh this is a really good idea and could explain why the LOC could work with one amp and not the alpine. The alpine could be less sensitive (expect more voltage) on the RCA's and somehow tell the LOC signal to shut off. Sub's at 4 ohms nominal, metered with a fluke to be like 3.7 ohms. Don't think the amp fuse is the cause seeing that it worked in my car. I really think you're onto something with the speaker level input though!
islandpride684 Posted August 15, 2014 Report Posted August 15, 2014 what kind of car is it? your signals might be crossed so a regular loc will not work, you need to sum the output signals.... Build Log http://www.stevemeadedesigns.com/board/topic/186921-blk9te-07-yukon-slo-mo-build/page-3?hl=%2Bblk9te#entry2881410
csshakka Posted August 15, 2014 Author Report Posted August 15, 2014 what kind of car is it? your signals might be crossed so a regular loc will not work, you need to sum the output signals.... 2014 focus hatchback ...st or se....whatever the sport model is haha
Recommended Posts
Archived
This topic is now archived and is closed to further replies.