Second hand sub and amp

[private number]

Hey fellas. Is there anyway to test if a sub and amp is in good working order if it's all out of the car?

[DJKOR]

Without connecting it up and having a good listen to it, there is no real way to determine the operating condition of a speaker/amplifier.

The best you can do without setting it all up is to visually inspect the driver by making sure the suspension is free of wear and tear and that the cone is in good physical condition. As for the amplifier, visual inspection may not really give you much indication.

[private number]

Sweet thanks for that dj. I'll just try and convince him to quickly set it up for a test run and I'll inspect them areas too

I could also set it up outside my car using my headunit and battery to see if it works too correct? Probably would kill 20mins but it's good to test it aye

[private number]

Edit. Double post

Edited November 7, 2010 by private number

[SteveAndBelle]

+1 to what DJ said... however if you want to go the extra mile you could connect it up to your car battery being careful that you don't get the polarity wrong of course.

You'll need the positive & negative (obviously) to the main amp terminals and can just use some reasonable thickness speaker wire for that but you'll also need to get a positive feed to the 'REM' connector to turn the amp on. You can do this by bridging the power from the positive terminal with a small piece of wire. Then you need an audio input. Just use your mobile phone headphone output or iPod headphone output and connect it straight into the amps RCA inputs.

Before you start testing though be sure the volume of your music source is down and make sure the amp gain controls are pulled down too otherwise you might end up doing some damage.

Good luck.

Steve.

[private number]

Cheers for that! Me and electronics go together like vodka and milk. No good LOL but ill drag along my auto elec mate and see if he knows this process

I did some researching last night and i heard about a 9v battery test and a test using the multimeter?

It was something like if you connect the 9v battery to the sub, once you connect the last wire the sub will jolt meaning its in good working condition. Obviously need to inspect the components too before testing. And to test the amp, i think they said they used a multimeter to see the reading?

Edited November 7, 2010 by private number

[eviltwin]

What i have always done in the past is called a mate with an amp installed in the boot and asked kindly if we could quickly throw the amp i was looking at in for a test . I would say i'll give you a hand but i no longer install amps in the back. Good luck!

[private number]

Damn good idea aye! Why didnt i think of that LOL -.-'

But i doubt any of my friends could be bothered/would want to drive me to dandenong all the way from the west side.

They dont mind coming along, aslong as i drive. since afterall, this is my business LOL

[eviltwin]

in that case maybe just ask the seller if he could show that it works. If he refuses then just move along to someone else...

[DJKOR]

Cheers for that! Me and electronics go together like vodka and milk. No good LOL but ill drag along my auto elec mate and see if he knows this process

I did some researching last night and i heard about a 9v battery test and a test using the multimeter?

It was something like if you connect the 9v battery to the sub, once you connect the last wire the sub will jolt meaning its in good working condition. Obviously need to inspect the components too before testing. And to test the amp, i think they said they used a multimeter to see the reading?

The 9V battery test is only really for testing the polarity of the speaker. If you ever have to do this, only apply the power as a quick tap, just enough to see which direction the cone moves in. You shouldn't have a need to do this. It won't harm the speaker in a quick pulse, but it's always better not to do what you don't need to do. It will not give any indication of the condition of the driver... unless of course it does nothing when you give it a quick jolt.

As for the multimeter, only really good for testing if the voice coil hasn't been burnt out as it will show resistance when the multimeter is set to test that. This is about all you can do with the multimeter. You can't measure the driver's impedance with a multimeter... only it's resistance, which is not the actual impedance of it as stated in it's specification.

A multimeter connected to the output of the amplifier will give no indication of it's condition... unless of course you get zilch readings.

[SteveAndBelle]

I did some researching last night and i heard about a 9v battery test and a test using the multimeter?

It was something like if you connect the 9v battery to the sub, once you connect the last wire the sub will jolt meaning its in good working condition. Obviously need to inspect the components too before testing. And to test the amp, i think they said they used a multimeter to see the reading?

Yep, that's a basic test to see if the voice coil/s of the speaker driver aren't burnt out and although it does the trick it may not identify all the problems. Sometimes a speaker can produce a scratchy sound if the voice coil has been driven hard and has heated up too much and you may not hear that until you drive the speaker at low-medium levels. Do the 9V test though as it should identify most problems especially if you also flip the battery over to make the speaker cone go the opposite way without any problems too... just don't leave it connected more than half a second though OK :)

The only 'easy' way to test the amp however is to power it up and drive the sub with it. You can do heaps of bench tests to make sure it's OK but you can't really do that on the side on the road or in someones front yard :P Just connect it up to your battery (best to get the current owner of the sub & amp to do it all for you so he can't blame you for frying it) and plug in a signal source. Easy and will only take about 60 seconds to do.

It'd want to be a good price though because you can get some pretty amazing bargains out there nowadays. Low-end yet decent 12" subs in boxes with amps now sell for as little as $150 and come with warranties etc. so for $250-$300 you can get pretty decent 'starter' type gear that will blow your eardrums but not your budget. Check out a review I did a few months ago on some of the cheapies here: http://au.toyotaownersclub.com/forums/index.php?showtopic=28883

Steve.

[private number]

DJ; Ohh no doubt. Makes sense. thanks for that info!

Steve; I convinced the seller to test out the sub and amp in his car before buying and he agreed! JL 12" sub and JL amp for 120 = steal IMO! bargain! That was a good read! im only just trying to learn about car audio so that was a good start. Ill forward that thread to some of my mates who are lookin for cheap subs and amps!