qbodsyt

iTrader: (2)

Hi all,

Ok, here's the deal. I've wired several simple single amp/single sub setups before.

I was running a cruddy Pioneer amplifier to my Kaption SPL1200 sub (I know, lousy match-up) planning to run an Alpine PDX 1.600 amp in the near future.

I built a box for my buddy and ran his box/sub/amp off of my already run wiring for a week to make sure it was all good. I disconnected my amp/sub from the existing wiring and just plugged his in. Good to go, no issues.

Then I go and help my buddy wire up his newly built system together, run the whole wire scheme, works first time, no issues.

Lastly, I go back and hook up my amp/sub back up to my wiring. It blows the 25amp fuse in the back of my amp. I put another one in and it blows again.

Stupidly, since I had no more 25 amp fuses left, I decide this would be a perfect time to go and wire up my sexy new PDX amp. I disconnect my old amp, plug everything into my new amp.......as soon as I connect the negative cable to the battery terminal, my main feed fuse blows. I sigh and go to the shop and pick up some new fuses. I put the new fuse in without disconnecting the neg. cable, it doesn't blow, I go in and turn my stereo on....and the hot blue light on the PDX....doesn't turn on. I turn the stereo off, and check my amp, and all 4 20 amp fuses in the back are blown.

What's going on guys? I'm grounding to the inside of the engine bay, so the ground cable is like 8' instead of 3', but I've been using this setup with no issues up til I plugged my system back in this week. What am I doing wrong? TIA

patotay

hey bud,i had the same problem in my old set up.but the problem was my amp,i bought it with factory defect..anyway DO NOT disconnect the neg. cable. negative should always be plugged first before the positive to run the power through it..that's why you blew fuses even the fuse in the fuseblock.your amp was eating power from positive of the batt but doesnt have the negative connection to balance your amp electricity.check your amp's negative to the chassis,clean it or use papersand for rust or dirt.let somebody check your amp before anything get worst..correct me if i said somthing wrong..

me myself have alot of questions also regarding electricity...hope this one help buddy..=)

JohnVroom

if a fuse blows once there is a reason, it is not a 'bad fuse' or luck it is an electrical fault if you change fuses more than once you are asking for permanent damage to the amp.

it could be the amp or the wiring, since this happened to more than one amp it is the wiring. It is no doubt the speaker wiring. Get a digital multimeter and fix the shorted output

patotay

to john,
what do you mean "It is no doubt the speaker wiring"? does it affect the fuses bud?

qbodsyt

iTrader: (2)

ok, I definitely see what you mean.....thanks

I have no doubt that my wiring scheme could use some improvement.....but then why was it working perfectly right up til I put my amp back on.....like I was literally listening to my friend's setup one minute, then blowing the fuse in my amp the next. Why did it suddenly start shorting? And what exactly do you mean by "fix the shorted output"??? Thanks again

JohnVroom

Q-Well what makes a fuse blow? A-excessive current.

Q-why would an amp (and then a second amp) 'suddenly fail?
A- the fault is external to the amp, if only one of the two amps had this problem that would indicate an internal fault.

Q- would a power supply issue blow fuses?
A- well if it denied the amp enough voltage I guess it could but that is fairly unlikely

Q- what caused his problem?
A- swapping amps in and out enough times to cause an issue with the wiring (pulled a little to hard one too many times or a speaker wire worked its way to where it shorted). an open circuit will not blow a fuse, a speaker wire to ground connection could blow a fuse (though it generally exhibits other issues instead) and a speaker short will blow the fuse (every time). Power wire issues are seldom a fuse blower though with enough effort you could probably do it. These problems arise when one starts becoming "comfortable" working on their car audio system, if you were "uncomfortable" then you double and triple check connections prior to powering back up. This is common, it can happen to a noob or even an MECP installer.

JohnVroom

there are 3 basic wiring faults 1-Shorting (very bad), 2-Grounding (from not good to very bad), 3-opens (the system produces nothing but silence but there is no expensive piece of equipment going up in smoke)

An electrical circuit is a 'circle' or a complete circuit path (battery +to wire to amp+, then from amp - to car chassis to battery -) or (amp+ through wire to speaker + through speaker to speaker- through wire to amp-)

1- Shorting is where the electrical path takes a shorter circuit (in this case skips sending power to the speaker and the outputs of the amp are basically shorted together)

2-Grounds- this is where a faulty connection involving the cars ground or - voltage plane is involved

3- Opens- the electrical circuit isn't complete or 'closed' (the power never makes it to the speaker)

if someone has actual text book definitions for these car audio terms please feel free to post it as I am paraphrasing (poorly IMO)

qbodsyt

iTrader: (2)

Thank you, that was actually very informative, even if the paraphrasing was subpar.......

I'm trying not to get too concerned about at least my PDX amp as it is supposed to have very good internal over current protection........but obviously just changing the fuses over and over isn't going to solve anything....it'll just cost me money and increase the risk of internal damage.

Tomorrow I'm going to go and buy new lines that are a higher gauge than my current setup (8 gauge, uprgrading to 6 or 4) and buy some 80A fuses for the main power line (currently 60A, but it should match the amp's 4 20As)

I'll just re-run all my lines again and do like you said and not get too "comfortable" with my abilities. Unfortunately I don't know DC theory as well as I should to be doing this, I've just been relying on general sense and observation til now. I wish there were more stickies on this site as it is full of great information. I'd much rather search and read then post like this (it's kind of embarrassing to advertise how stupid you are like I'm doing now!)

Thanks again

patotay

hey john,thanks buddy! thats alot of learn!=) QBODSYT goodluck bud=)
see you around guys..cheers!

qbodsyt

iTrader: (2)

Just to let you know...

I pulled out all my old wires and ran new 4awg wire to the back and ran a new 24" ground line to the chassis right under the sub. My heart was trembling as I reattached the negative cable to the battery, but it worked!

Now I just have to figure out the tuning on my new setup.......that PDX unit is uberslick!

Thanks for the advice and education!