# Fuse Suggestions and Concerns



## Hades16x (Feb 5, 2012)

Hey all - first post - mods please move if this isn't the most appropriate forum.

If you want to skip right to the problem go down to the next *bolded* section

I bought a 2011 Fiesta on 3/14/11 - and the premium audio system really sucks, but I very much liked the factory integration with sync/sirius etc and the proprietary dash is not very single/double-din friendly - so base of the system was an Audiocontrol LC8i. New components/coaxil are amplified by an Alpine PDX-F6. At this point I was pretty much tapped out with funds, so against better judgement, I ripped my (older) Alpine PDX 1.1000 out of my (sitting) 1983 Mercury Capri.

I've always had issues with this amp - from blowing subs that were "professionally installed" to carrying a box of fuses in the car for replacement when needed. Bought the amp when I was 18, am now 23 with a degree in EE from University of Michigan. I hope my money spent into my degree doesn't make me seem unintelligent, although I understand education is only half the picture; experience is the other.

I understand why these components are usually only warranted by installs from professional and authorized installers - all the safety checklists will(should) be checked - but I feel confident.

I should start - I do not have a HO alternator, nor have I replaced the factory battery, but all "ground" wires have been replaced (big 3), power is delivered by a single 0 gauge to rear hatch and all powered equipment is grounded with sub 14 inch 4 gauge to sanded, drilled, tapped holes in the chassis.

I feel very confident in my wiring - the only thing I've contemplated is running a 4 gauge from my amp "ground" location back up to the engine bay to alleviate any potential difference between amp "ground" to Big 3 "ground." Note, I would not connect this wire to "-" side of battery. I understand the risk that my amps would complete the circuit if anything happened to my battery.

I have a 250A ANL fuse just off my battery, and my distro block requires MAXI fuses as a part of the 0 gauge to 4 gauge conversion, which the F6/Audiocontrol (which later has an inline 5A fuse) has an 80 amp fuse, and the 1.1000 has a 100A fuse. 

I have zero issues on the F6 line, only with the 1.1000.

The 1.1000 was initially specced with 4x 20A fuses on the amp with locations marked and silk screened on it. I ended up calling Alpine and they told me the that unit later shipped with 4x 25 A fuses due to these issues, and to replace my 20A with 25A fuses.

This made sense, theoretically, but the first thing my dad taught -shoot my first phrase out of my mouth as a child - was everything was only as strong as it's weakest link and therefore I wondered if the internal circuitry could handle the extra 20 A of power in my older amp - and if the later revision had any beefed up circuitry. Well I switched to the 25A fuses anyways and I pop fuses less frequently, but they still blow.

So I start hunting through manuals and find the Alpine manual to be complete crap..... I'm a big manual (even if I don't learn anything) person and find the quality of a manual to reflect the amount of care and consideration and passion the engineers, marketing, and company want the user to receive the product. With that being said - Alpine's manuals suck - perhaps written by engineers, whom are not know for great proficiency (read my post ) in writing, whereas JL Audio's HD1200/1 has a very informative manual plus very thorough testing. That manual was actually bathroom reading material one day - perhaps only surpassed by Audiocontrol manuals which are a joy and almost comical to read.

The JL HD amp is tested and rated at various impedances at both 14.4VDC and 12.5VDC, but with a range of input voltages from 11-16V. It also states the amp will function with as low as 9V supply. This leads me to believe the amp will output rated power at as low as 12.5V, but will continue to function at lower output down to 9V input.

*Issue:*

The Alpine PDX 1.1000 is rated at 14.4V (11V-16V) - how its written. So I would assume the amp is only rated at 1000W RMS @ 14.4V into 2 or 4 ohm loads, but at any other voltage in that range, output power will vary - but the amp will function.

So now onto calculations... this amp came with a spec sheet and a in house testing of 1187 Watt RMS output. The amp is stated to have roughly 78% efficiency, but since the output must be >1000W, the input must deliver more than 1000 W right?

So here we go:

@ 1000W RMS output, input must be ~ 1280W
@ 14.4V - 89A
@ 12V - 107A

@ 1187W RMS output, input must be ~ 1522 W
@ 14.4V - 105A
@ 12V - 126A

Well the Fiesta's battery seems to hover around 14.02V while running, recorded with a Fluke 87 III. 

Testing has been done with the F6 disconnected for those concerned with power. The lowest the battery has read during a fuse blowout has been 11.92V using the Fluke record min (I understand voltage could have been lower for an incredibly small time window) and 11.89V at the amp terminals (same track same 'volume'). 

I understand fuses are not ammeter-ed fast acting switches, but rather time delayed, heat burning, filaments and because of this can allow very very short bursts > rated capacity. I assume this is considered the norm since many devices have ridiculous T=0.0+ current demand (inductive load etc) but will fall back into spec within a blink of an eye.

With that being said, I do not have an ammeter capable of withstanding 120A of current - so it's a little bit hard to see what current is required cause my battery to droop to 11.92V. The closest I could come up with would be to use a test tone CD, measure VAC across amp output during a blowout, square it, divide by the sub's impedance, and then divide again by .78, then divide for a last time by 11.89V to find my current @[email protected] Since Alpine does document 14.4V with a range of 11-16 volts, and my voltage is within that range, I feel I'm providing sufficient power to the amp. 

I want to assume the amp is good, but the 100 A Maxi that is within 1 foot from the amp never has blown, only the 4x 25A fuses. Last in line plus most sensitive? 

I feel that I've done quite exhausting troubleshooting that has led me to a few solutions and thoughts - can you help me order these?

A) Send the amp in for repair (faulty)

B) Spend some time on the phone with Alpine, and request (and pray) they may allow me to "step-up" to a newer amp (I've seen many issues with this amp eating fuses faster than the cookie monster) as I feel the amp might honestly not be specced for 100A loads judging by the initial 80A worth of fuses. (Highly unlikely)

C)Replace MAXI with an 80A with 4x25A fuses and see if the MAXI pops or

D)Replace 25A with 4x30A fuses to see if the 100A MAXI pops (last resort - understand I might fry the amp for good) which leads to 

E)Screw it- search for another amp that is within my budget, and with my gained knowledge, reviews - searching for issues and for me, better and well documented testing methodologies such as the mentioned, but not limited to, JL1200/1.

Thank you for all of your future and potential help!
Michael


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## eltico7213 (Oct 26, 2011)

don't quote me on this, but i remember my friend, who used to be an alpine dealer, said they had problems with the PDX amps from the box, and all they did was up the fuses, from 25-30 and from 30-40. i had no experience with their method, so i cant back it, but it doesnt hurt at this point to try it out.


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## Hades16x (Feb 5, 2012)

Well I just ended up calling Alpine. Gentleman replaced my PDX 1.1000 with a PDX M12. Arrived today.


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