Car amp died

[Sicklyboy]

So my car's amp has been dead for about a week. It's a Lanzar OPTS 650.5 model. Rated at 1360w max (I think it was like 150w x4 and 300w x1 RMS) 5 channel amp with subwoofer remote level control. It had stopped playing anything through channel 5 (the sub).

I took it apart, I see nothing wrong with the board. When I initially got it I had taken it apart and flipped and pasted all of the heatsinks because they were ridged-side down with no paste -_-. Heat shouldn't be an issue due to that and I also have a direct shot into my trunk for airflow - I always drive with the windows down or the AC on. Looking at it again now, I noticed that some solder joints were half-tinned, but I tested each with a voltmeter and they all showed continuity. For the hell of it, I went and filly tinned all of them. No cold joints on it.

I've ruled out the RCA cables and speaker wire. I've never seen a speaker go dead to the point where it makes NO sound, so I doubt that the sub is the issue.

The only thing, other than the sub, that I haven't tested is the head unit itself (specifically the sub outputs). I plan to hook one of the speaker channels to the sub channel on the amp and drive an old door speaker with it to see if THAT works.

Does anyone have any ideas?

 

[DinohScene]

It could be that a resistor has blown.
Or any other component has failed.

I also once tought my amp was dead cause it kept blowing fuses.
Turned out a little strand of copper wire was making a short between the + and -


First off.
Rule out the possibility that it's not the sub.

Then you can always hook the left and right parallel and the sub on another channel until you get a new Amp.

Fixing amps can be a major pain in the bum.


Edit: do you have a powercap hooked up to the system in parallel?

 

[Sicklyboy]

Already tried the source. Not the issue unfortunately :\ went from Pandora on my phone to my iPod to terrestrial radio. Nothin.

No, I don't have a capacitor in my system.

I know it's a cheap-o amp (I got it off of Amazon for like $80), but this thing worked DAMN well while it lasted. I hope it's fixable because I can't afford a new one right now, but I also want the satisfaction of fixing it.

Maybe I should cry more.

Edit - also, both 25A fuses in the amp as well as the 80A fuse in the line are good and show no damage.

 

[DinohScene]

Hmm.

I think that something must have shorted on the sub line.
Maybe you can grab a magnifying glass and inspect every single component of the Amp.

I still go with getting a new one or just applying a crude kludge to it to make it work for the time being.
It's just not worth it to trying to fix it since there are an extreme amount of components.

Heh.
I currently have a Spectron amp I believe....
Thing works freaking perfectly (4 channel and has some 300 watts of RMS idk really) in parallel with a new heavy duty 1F powercap (yeh my lights started to flicker ;p)

(Jealous? cry more.)

But I stll want a Rockfort Fosgate amp.
Things are the top of the line.
But if I do that I might as well ditch the Sony sub and go for an MTX Jackhammer if I really want to upgrade.
Maybe even a 5F+ powercap.

 

[Tom Bombadildo]

As Dinoh suggested above, check every little nook and cranny for something that could cause a short. Most Amps will go into protective mode if they detect even the tiniest of things and I know on some of the cheaper ones they don't have any indication other than no sound output if it's in said mode. I assume there are no LEDs or anything on it?

It could also be the headunit, as you've mentioned, so make sure you check that as well. My Amp was cutting out a lot recently and the RCA cables weren't snuggly anymore, so once I fixed that issue I had nice clean sound ever since.

Lucky me I managed to get a $150 amp for $90
Got a Kenwood 8105D connected to my Dual Bandpass 12" x2 Sound Ordnance subs

 

[Sicklyboy]

It does have two LEDS - "Power" and "Protection". Power is on when the amp is powered on (as it should). Protection, to my understanding, only lights up when there is a fault in the protection circuit in the amp - such as a fuse blowing or a short somewhere.

It does product sound on channels 1-4. My speakers drive fine, but my subwoofer isn't driven at all. No lows, not even any quiet highs.

Tomorrow (or saturday if I can't stay awake long enough tomorrow) I'll test it.

 

[DinohScene]

It also should light if it's overheating and shutting itself down to prevent damage.

Hmm.
You could hook up 2 speakers to channel 1 and 2 to channel 2 (if you got 4 speakers)
Then bridge the 3 and 4 for the sub.

Anyway, keep us noted on your findings and the eventual solution.

 

[Tom]

I've blown fuses before that showed continuity but didn't work FYI

 

[Sicklyboy]

I've blown fuses before that showed continuity but didn't work FYI

Just checked em with my voltmeter, they are continuative. If nothing else though I can replace em. Thanks for the idea

 

[Sicklyboy]

Played around with it today and I think it's the sub.

Did what Dinoh said and used ch 1 and 2 for front and back, running in parallel, then bridged 3 and 4 for the sub. All 4 speakers worked, but the sub didn't.

Hooked my rear out to the sub channel on the amp and hooked up my old JVC door speakers. Played music for a few seconds - heard nothing but buzzing, then the speaker seized and started smoking furiously. WHOOPS

Anyway, did the same thing with the sub, and nothing. Then hooked the sub to channel 1 with channel 1 hooked in and nothing.

I never did like this sub much anyway. I'll start looking for new ones, and go from there. If it still doesn't work, I'll throw my old radio in and test that out.

 

[DinohScene]

So it's not only the Sub that's dead it's also the other speakers?
Damn xd

Anyway now you know that your Amp still works fine.

So what sub/speakers are you looking to get now?

 

[Sicklyboy]

Ah no the speakers still work fine. If I have time tomorrow between getting home from the farm and going to work at Target I'm gonna re mount my amp and hook the speakers up. The speaker I fried was the old jvc door speakers I had. Sucks a little because they were pretty good speakers, but they were cheap too - about 37 off of amazon when I got them, so I'm not to disappointed. My Polk speakers still kick.

The sub makes zero sound, just like the speaker I fried. The box it came with isn't vented which might be why I never smelled anything. I'm gonna try running it off of my pc's HTIB to check it one last time.

As far as a new one, I'm not sure. I still want a 12,and I might try using the same box, but I'll end up venting it. I'd love to get a Rockford Fosgate, because from what I've heard they're beautiful, but they're so expensive. I also wouldn't even dream of this amp being strong enough to drive them. I'm probably gonna get a Sony Xplod, they're pretty good; I'm gonna see if I can find anything in my area as well on craigslist. After I got my setup (btw, my sub was a Pyle PLBS12. I've never been super happy with it) I looked on craigslist a few weeks later and found a guy selling 2 10" Rockfords and a box for 70 bucks. I was so jelly.

 

[DinohScene]

I still "rock" with standard door speakers from 1996 ;p
Cba to upgrade them since pretty much all of my sound is in the back.


Ouch.
Large speakerbox or small one?
Since it's always way better to vent large sub boxes/compartments.
They move a big volume of air so they could blow themselves out ;p
Not only that but it also gives a much clearer sound.


Get an Xplod yes.
I also got a Xplod Sub and I'm incredibly satisfied with it.
It has the power to let my whole car visably vibrate ;D
Best bang for your buck.

Damn ;o
Neighbour of a friend of mine was also selling a custom made box once.
It had 2x a Rockford Sub + 2x Mid+high freq speakers, 2000 Watt RF amp + 2 F RF powercap.
He sold it for ~700 quid as I recall.

Reason was that he didn't felt comfortable anymore having that kind of expensive audio in his car, in a crime ridden city ;p

edit:
Mind to share a pic of your setup (old pic or once it's finished)
I'm pretty interested in what you got in the back ;3

 

[tueidj]

Just check the resistance of the sub itself, should be around 4 ohms (might be 2 depending on the model). If the resistance is very low, it's good. If it's high, it's probably bad. If there's no continuity at all, it's blown. Try to check as close to the actual coil terminals as possible to rule out faulty wiring. Most speakers won't do anything when they blow (like smoke or smell) since they're mostly just a wire coil inside a magnet - a tiny part of the coil burns out and it's game over. It's only when the coil shorts itself instead that things get interesting...

 

[Sicklyboy]

[member='tueidj'] - Man, I would have never thought of checking that if you hadn't posted it. I checked on the terminals on the speaker, it's showing infinite resistance (no continuity).

Thank you

And for reference, I checked the other speaker of that JVC pair that I blew, and it's showing ~4.5 ohms resistance on the terminals.

 

[DinohScene]

@tueidj
It never even occured to me.
Damn I feel derpy xd

 

[Sicklyboy]

http://www.amazon.co...=pd_sim_sbs_e_3

I might buy that and a cap to drive whatever new sub I get, keep my current amp for the door speakers.

Edit - because yeah, I drove my system pretty hard on pretty cheap equipment, but I'm afraid if I get something nice, something even higher powered than my current sub, I'll end up under driving it and fry that.

 

[DinohScene]

New sub should be vented then ;p
800 watt ish should be difficult to blow up.

Also don't forget to charge the cap first (if you get one with a remote),
If you forget to charge it there is a very big chance that it'll blow out the fuse in the 12+ line from your battery to your powercap.
And be very careful not to short it.
Those things are nasty nasty buggers since their infact a secondary battery, but more powerful.

 

[Sicklyboy]

I've read all about the type of stuff they can do when mishandled XD

So I set everything up again, sans subwoofer. Working great and sounds pretty good too. I really miss the extra bass kick, but my in-dash equalizer adds a bit more in the rear. So for now, I'm satisfied enough. I need new shocks for my car before I can get anything else.

 

[DinohScene]

Nasty things indeed ;p
But a sweet addition to the total setup and they prevent battery damage from the fluctuating voltage line.


Good luck on that ;o
Those are quite expensive.