amp problem

[ram1n]

wondering if some light could be shed on this....

recently installed a 10" sub, 300w amp and 300w max wiring kit.

problem is when the bass gets too constant and deep, the fuse in the amp blows. i bought the amp second hand and it had a 15w fuse when i bought it which blew, when id replace the fuse it would keep blowing, i stepped up to a 20w fuse but they kept blowing too. im not sure whether to move to a 25w fuse incase it burns out the amp.

look forward to seeing some replies.

 

[Sando]

When the bass gets really deep and long the amp will be drawing a lot of current so the fuse (if its too small) could blow. Im no elctrical genius so Im not too sure, have you chescked with the manufacturar what fuse should be in it?

Matt

______________________________________________________

Signature space for rent, reasonable rates, apply within.

While most Cinqs are unreliable...mines just taking the pi55

 

[Donz]

what brand is the amp? with the model number you could prolly find out on the web what size fuse it should have....

- - Donz - - ​

 

[The Negotiator]

The fuses you quote aren't measured in watts but amps. They give the maximum current they will allow through before tthe filiment melts. Don't say a fuse "blows", it melts, well, it would get you into trouble if you were doing physics exams! LOL

Basically, I know very little about ICE but i know a little about electronics.

Using formula Power = current x voltage you can work out the maximum current your amp will draw.

You quote 300watt amp, assuming that this is the maximum it will go up to (is that a correct assumption?) and you are using a 12v supply:

P = I x V
300 = I x 12
=>I = 300/12
=> maximum current draw is 25amps.

Allowing for any extra in a domestic appliance you might even go for a 30amp fuse which would allow for slight fluctuations.

In my opinion, I would try a 25amp fuse (which is basically a 300watt fuse if you want to look at it like that) and see if that runs. If it also melts then you should safely be able to go up to 30amps. If this blows it is time for a rethink.

The thing is, at the moment, with a 20amp fuse you are limited to 240watt power draw but if you are using it above this you will experience a melted fuse.

Fuses are cheap, if it were me I would try a 25 then go up to a 30.

If the guy before you used it nicely with a 15amp fuse find out if he used it at high volumes. If so, and you are experiences a melted fuse at low volumes the problem isn't a too small a fuse and it is more likely to be more fundemental than that. A fuse will melt if the current flowing through it is too high and this will allow happen if you have a short circuit. Check your wiring and do some continuity checks if you have the means with a multimetre.

Again, my knowledge is NOT based on ICE but on general electrics/electronics.

Paul

 

[mckrob]

[:0]

Cinq Sporting 1997 https://www.fiatforum.com/forum/topic.asp?TOPIC_ID=8033 Parts Needed!

 

[The Negotiator]

[?]

 

[The Negotiator]

If my advice is awful in the context of ICE please tell me and I will remove it!

 

[ram1n]

cheers for the replies people.
pghstochaj cheers for working it out i have stepped up to a 25amp fuse and it was running well, but now the amp is cutting out but the l.e.d lights on the amp are staying on, so it is not powering off but the sound is cutting out. i think it might be something to do with the connection? because the sub works again after switching off then back on the head unit. although i have double checked, think its best just to take it to a specialist.
as for checking its model number etc i think the amp may have been stolen as it has had its model number and info sticker on the back badly removed, and the bloke has not replied to my email, but hey thats ebay for you.

cheers for the help.

 

[GhostWKD]

I've got that exact prob! under heavy braking the amp will cut out, havnt checked power led thingys tho

Cinquecento Sporting,
and yes it is indeed Broom Yellow \o/

Only mod so far, poppy coral air freshener

 

[MrDerv]

try a 30 amp fuse, that's what my old 200w amp ran



There's a certain satisfaction you get from driving over a Sleeping Policeman

 

[ram1n]

tried a 30amp fuse and same thing still happned.
i dont think it cuts out when the car is parked, but it cuts out when moving, even when not braking or going over bumps. so i guess its a connection problem in wiring or the amp.

 

[Sando]

Check the entire wiring, maybe its rubbed down through the plastic into the cable metal. Could it be clipping?

Matt

______________________________________________________

Signature space for rent, reasonable rates, apply within.

While most Cinqs are unreliable...mines just taking the pi55

 

[The Negotiator]

As I said, constant killing of fuses is usually a short circuit.

 

[MrDerv]

you got a duff amp then if it's blowing 30 amps



There's a certain satisfaction you get from driving over a Sleeping Policeman

 

[mckrob]

pghstochaj: The [:0] face was because i never thought things they taught in school actually help in real life situations

Good on ya' son, i'll give you a call whenever i need help

Cinq Sporting 1997 https://www.fiatforum.com/forum/topic.asp?TOPIC_ID=8033 Parts Needed!

 

[The Negotiator]

I do my best

It doesn't help much does it, school I mean. That must be the first time in weeks I actually used something I learnt at school and I don't exactly hold back in terms of stuff I do, make and design etc.

I love that formula (P = IV) I knew it before everyone else for my GCSEs and hence it is my favourite LOL!

Any time, if i can help, I will

Paul

 

[James M]

Nice1 Paul, having worked in electrical engineering, I know what you say is correct, and sizing the fuse larger than the maximum demand is also correct.

If you are still getting fuses blowing, then your amp is drawing too much current, and has a fault, don't be tempted to use an over size fuse (or other protection device) as this will merely move the problem elsewhere, which begins to become dangerous, the idea of a fuse is so that it will fail safe!

53 3d Stilo Dynamic JTD - Sprint Blue

 

[The Negotiator]

 

[Sando]

Have an audio repair shop take a look at it. It depends on the amp and how much you paid for it as a repair shop may cost a bit and maybe it would be more cost effective to buy a new amp.

Matt

______________________________________________________

http://www.zen8627.zen.co.uk/Matt/

While most Cinqs are unreliable...mines just taking the pi55