Hi guys. I just decided to rebuild my radio after about 8 years. My old
sub amp was a mtx 2300. I thought it had kicked the bucket so I bought
a hifonics brutus 1500d to replace it with. I ordered 2 more subs
(kappa perfect 12.d's) to go with the 1 I already have. Tonight I got
in my componets so I installed them and I thought what the heck ill
stick one of these old crap amps in and run my sub till my other 2 subs
and my amps get here. Ive got some old 300 watt amp and the sub is a
dual voice coil wired at 8 ohms so I thought "i hope this will make the
cone move" ....so i put it in and wala: THe protection circuit came on
after about 2 min and the amp wouldnt come on anymore. So I took it out
and put in an old coustic amp that said 125 bridged. so at 8 ohms that
will be a big 75 watts. after I put it in the 20 amp fuse blew after 5
min. So I go to the store and get a 30 amp fuse and the amp plays for
about 10 mins then the protection circuit comes on. So i go look at the
old mtx amp and all 3 30 amp fuses are blown (it was an old amp that
had too be sitting a certain way to play anyway). My questain: these
are old amps like 6 to 10 years old. I dont know if these amps can
handle the 4 volt preouts. The amp quit the day I put a new headdunit
in. But if that is the problem why does my old mtx 2160 that is running
my componet set not blow fuses. Any u techys out their got any Ideas. I
dont wanna stick this sub in parrell with my new subs too my new amp if
its scew up all my new stuff.....but while it is playing, it sounds
fine? Does infinity refurb?

Sounds like your sub is blown or your speaker wiring shored out somewhere. The
reason you are blowing fuses is more then not because you blown the output
transistor in the amp/s. Unplug the speaker wires from the amp and with an ohm
meter check for a short. If all is fine you should see around 7.5 - 8.5 ohms.


In article .com,
wrote:
Hi guys. I just decided to rebuild my radio after about 8 years. My old
sub amp was a mtx 2300. I thought it had kicked the bucket so I bought
a hifonics brutus 1500d to replace it with. I ordered 2 more subs
(kappa perfect 12.d's) to go with the 1 I already have. Tonight I got
in my componets so I installed them and I thought what the heck ill
stick one of these old crap amps in and run my sub till my other 2 subs
and my amps get here. Ive got some old 300 watt amp and the sub is a
dual voice coil wired at 8 ohms so I thought "i hope this will make the
cone move" ....so i put it in and wala: THe protection circuit came on
after about 2 min and the amp wouldnt come on anymore. So I took it out
and put in an old coustic amp that said 125 bridged. so at 8 ohms that
will be a big 75 watts. after I put it in the 20 amp fuse blew after 5
min. So I go to the store and get a 30 amp fuse and the amp plays for
about 10 mins then the protection circuit comes on. So i go look at the
old mtx amp and all 3 30 amp fuses are blown (it was an old amp that
had too be sitting a certain way to play anyway). My questain: these
are old amps like 6 to 10 years old. I dont know if these amps can
handle the 4 volt preouts. The amp quit the day I put a new headdunit
in. But if that is the problem why does my old mtx 2160 that is running
my componet set not blow fuses. Any u techys out their got any Ideas. I
dont wanna stick this sub in parrell with my new subs too my new amp if
its scew up all my new stuff.....but while it is playing, it sounds
fine? Does infinity refurb?

.. My questain: these
are old amps like 6 to 10 years old. I dont know if these amps can
handle the 4 volt preouts. The amp quit the day I put a new headdunit
in.

I agree with Ct. Howdy. They have been making decks that put out 4 volts
since 1990 (beginning with the Alpine 7909), and for the last 13 years many
have used line-drivers to raise their output voltage as high as 8 volts with
no ill effects. This is definitely not the problem. As Howdy said, there
is a problem with your sub that is causing the impedance to be much lower
than it should.

Check to be absolutely, positively sure it is wired correctly (in series,
not parallel) as that would PERFECTLY explain these symptoms. I doubt it's
a short as you would have no sound at all and your amp would IMMEDIATELY go
into protection mode.

My $.02

MOSFET

0.5 of an ohm is almost a dead short ( well 0 ohm is) and some amps will work
all day long at that load. Protection Mode of most amps is nothing but a sick
joke. I have repaired countless amps with protection that had blown input
and/or output transistors. Last summer the kid next door bought a bazooka non
power box on ebay along with a mono profile amp that had protection also. So
there I am talking to him as he just finished his install. The kid is all
pumped up and ready to show off his new gear, as it turnes out the sub's coil
was preburnt but not stuck. He turned the **** on and it play for about two
minutes then the big ass power light on the amp started to flicker and turned
off and the smoke just started rolling out of the ports. Funny as **** to see.
Mind you when I stuck and an ohm meter on the sub, it still showed 1.5 ohms
and pushing on the sub by hand sounded crunchy as hell. The kid was in tears.
lol
It all turn out all right, the place he bought the box from was local and they
exchanged it, and I repaired the amp with $10 in parts. I didnt even charge
him for the parts, you just cant buy entertainment like that for $10 lol. So
boys and girls when buy a used sub from ebay or anywhere else have it checked.
lol



Check to be absolutely, positively sure it is wired correctly (in series,
not parallel) as that would PERFECTLY explain these symptoms. I doubt it's
a short as you would have no sound at all and your amp would IMMEDIATELY go
into protection mode.

My $.02

MOSFET