Just installed this system yesterday..

I keep blowing the 20 amp fuse for the amplifier.

I've searched and my issue points to an impedance matching problem or amp problem, but Im not sure..

The Gear:

Brand new wiring kit, 4 gauge power/ground, 60 amp power wire fuse, all connections crimped, soldered, shrink tubed and vinyl insulated.

6.5" sub and ported box from the most common home office set up ever Altec Lansing VS4121

The amp: Alpine V12 MRV - T300

Now I know this is a whack system.. It is more or less an experiment.

All wire included I have 42 clams total into it.. the outputs on the sub for the satellites were toast anyway.

Additional info

I soldered my speaker wires directly to the sub and then ran them to the amp bridged.

My guess is its putting out around 100-150 watts rms at 4 ohms, or according to that german website: 1 × 182 Watt Kanal 1 + 2 gebrückt an 4 Ohm lol
I tested the sub before doing all this and it was 4 Ohms solid on the DVOM. I dont have a clue of the rms wattage handling

With a fresh fuse in and the sub works perfectly, then all of a sudden the fuse goes..

It doesn't pop right away or on a particularly bass filled song either. I would say it works for 10-20 minutes each time.

Questions

Is it safe to assume that my wiring is good and rule out a short? Since that would pop a fuse immediately after powering up, right?

Should I just turn the gain completely down, replace the fuse, then slowly turn the gain up bit by bit every so often to see how much I can get away with?

Will the gain level alone even blow a fuse? Or is it most likely there is another problem? Any trouble shooting I can do? The amp is used/ancient/cost me $20

Thanks for any insight.

I'm guessing that everything is fine. You're just trying to get too much power out of two small an amp.

20A is not enough current capacity to power a sub to audible levels. The amp was designed to be used with speakers. It's "capable" of running a sub, technically. But not practically.

Thanks for the reply.

That makes sense.. I thought I would be ok since the sub is so small but apparently not..

Oh well, if this doesn't work out I'm only out my time, the cars wired for subs and then I have a spare mid amp.

Those little home theatre subs aren't necessarily efficient. They are hooked up to mains power, after all.

Why don't you try running the sub off either of the single channels before writing it off? Also, try it on one of your other speaker channels that are working fine.
I once ran an old Sony HT sub on an oem rear channel before I knew what the hell I was doing and it was certainly audible though obviously it sounded like poo.

bradsk88 wrote:Those little home theatre subs aren't necessarily efficient. They are hooked up to mains power, after all.

Yeah.. I had that in the back of my head the whole time, I really wasn't sure it would work at all to be honest.

..but once I had the subwoofer apart and seen that it had a resistance of 4 ohm and such dinky wiring going to it I got hopeful.

I'll throw up some cell pics I took when I was thinking it out when I first tore into the job.

RoboticPotPie wrote:Why don't you try running the sub off either of the single channels before writing it off? Also, try it on one of your other speaker channels that are working fine.
I once ran an old Sony HT sub on an oem rear channel before I knew what the hell I was doing and it was certainly audible though obviously it sounded like poo.

Thanks for the reply. I thought about doing that but I figured bridged would be the way to go for the most power and less chance of damaging the sub, I may still try that to see if it changes anything, this system has kind of been my guinea pig lol

Update

I just spent about a half hour in the car tinkering around with the the tuning and it didn't blow the fuse under normal usage, then right before I went in, with all other setting off or at min, I tried turning the gain level on the amp up slightly and the sub level on the head unit and the fuse blew..


Probably just going to run the 2 way coax 6.5"s I have up front, off the V12 amp. I know they are begging for more power..

I was really just trying to get something temporary going for cheap, but in reality the 6x9s put out more lower end than the sub is allowed to without blowing a fuse..

pics for the helluvit

lol i see the piston you cracked trying to get the pin out.

you out that system in the cav? how much bump you getting from a 6.5 woofer. i was so close to buying a sub last week but im trying to dump the fire for a vw

What's the impedence of that sub? Sometimes they'll give it a goofy impedence of like 3 ohms or 6 ohms.

the_miker17(u kiddin) wrote:you out that system in the cav? how much bump you getting from a 6.5 woofer. i was so close to buying a sub last week but im trying to dump the fire for a vw

You can still throw the system in your new ride, get out of the J game while you can!! haha jokes.. what kind of vw? too bad the ae86s are so hard to find here.

Surprisingly there was probably a half hour window where the amp and sub were working pretty good in unison, the 6.5 woofer may not seem like much but the install is half the finished product and the ported box helps. It certainly was not a ground pounder but you could tell it was there, filled in a lower end that was previously not there and took a lot of stress off the 6x9s once the high pass filter was set on the head unit, and low pass on the amp, sounded pretty good.

the_miker17(u kiddin) wrote:lol i see the piston you cracked trying to get the pin out.

I actually cracked that piston trying to get the rod pin back in lol.. still makes me wonder to this day if it was the wrong pin..

Lanman31337 - Cavfire wrote:What's the impedence of that sub? Sometimes they'll give it a goofy impedence of like 3 ohms or 6 ohms.

It has 4 ohms inked onto the back of the magnet, and the meter verified this.

I originally ripped this thing apart to fix the satellite outputs that ran from the back of the unit, but they were encased in plastic and sealed with a heavy white glue, which was then glued to the circuit board.. so when I saw that the woofer had an impedance of 4 ohms, I got to thinking.

Thirsty Z wrote:
You can still throw the system in your new ride, get out of the J game while you can!! haha jokes.. what kind of vw? too bad the ae86s are so hard to find here.

.

it is an 02 golf gti. 5speed fully loaded(no leather) and it is awesome. still trying to work out how i am going to pay for it tho lol.