Amp keeps blowing fuses?

right have been installing car sound system all morning and amp keeps blowing fuses i have earthed amp to negative battery terminal where am i going wrong i have done this many times and this is the first time this has happend i assume i have got a hort some where where should i start looking i installed headunit this morning got that going good any im no further please help!

Is it blowing an internal fuse or the large fuse that folks tend to put in series with the power wire from the battery! You could do a cheap cheat and get a 12v load like a 12v lightbulb, remove the + and - leads from the amp and connect them to the bulb. If it lights up, the wiring is 'probably' OK. otherwise if the fuse blows, there is a short on the earth return / ground. If the fuse blows regardless of a load, and whenever you connect the + side to the battery, the + line has a short to earth. If only the amp is causing the supply line fuse to blow, the amp is faulty. quadruple check your connections, then perhaps consider getting the amp seen to by someone who makes a living fixing that sort of thing. My 2c, good luck :)

Well.for a start, don't earth the amp to the battery.that's just silly.
Attach the earth wire to a bare steel part of the vehicle. Find a spot with an existing hole, wire brush or sand it back to bare steel, strip your earth wire and crimp on a lug http://tinyurl.com/492vdy8 of the correct size, then use a nut and bolt to firmly attach ii to the vehicle. Do you have a correctly rated in-line fuse fitted within 30cm of the battery! You should. http://tinyurl.com/4ut6xgf
Check the specs of your amp online for the correct fuse amp rating.
Check the fuse on the amp itself that it correctly rated also.
Basic amp wiring:
+ direct to battery with in-line fuse
- direct to chassis/bare metal (shorter the better)
remote wire from amp goes to blue wire on the head unit.
Make sure your + and - cable are the correct gauge (thickness) for the amps output.2mm wire just wont cut it.
Also make sure there are as few joins as possible in the + cable.the only cuts and joins should be where the in-line fuse is installed.
Also make sure you use a suitable lug to connect the + wire to the battery and that all connections are nice and tight.

Buying some heat shrink is a damn good idea also to cover the lugs once they have been crimped.
For connections at the amp, I would recommend using fork type lugs/connectors and heat shrink.this will eliminate the possibility of the + and - touching and causing a short.
http://tinyurl.com/4lqparj

http://www.installdr.com/

http://www.the12volt.com/

If the hole to be used is painted, there is a better way. Earth bolts often have a grove cut into them which removes the paint as they are screwed in, also removing the need to sand back the painted top surface (which may lead to rust and a poor contact). If you can't track down an extra earth bolt, steal one from another earth cable. The paint on the thread will have been removed so using an ordinary bolt should be okay. Inspect the thread in the hole to be sure.

got it sorted a couple of what i suspect to be resistors have comes off inside amp amp will need to be repaired!