issus with big amps

[QRAF]

So after having a great talk with matt on friday i started to think i need to upgrade my amp and he had some great deals don\'t get me wrong but the db racing crew on facebook have a lw2600d for sale for cheap it\'ll produce 2600w rms @1ohm and 1800@2ohms but i\'m thinking i\'m going to be limited to how much i use it.

I\'m wondering how much does my alternator produce as the amp with use about 200amps so i can\'t see my battery lasting long.

[boon]

Standard alternator is about 90A

Don\'t worry about it. I\'ve run way, way bigger amps than that off standard alternators.

The amp will only pull 200A when it\'s absolutely flat out. When you\'re listening to music, rather than playing test tones, your actual current draw will be more like 20A. Thanks to the joys of impedance rise your sub will be more like 20 ohms most of the time.

EDIT EDIT: I\'m not totally in love with the LW amps, but if the price is right go for it.

[QRAF]

yeah i\'ve heard newer soundstream aren\'t the best amps as there getting made cheaply, thats why i thought i\'d buy an old 2nd hand one yeah its only $450 so pretty keen

[ADIKT]

Just buy a decent battery

[QRAF]

got an example of what a good battery is?

[Scoobydoo]

If you\'re keen on getting into some decent sounds... some good deals can be found here: https://www.facebook.com/groups/109570779225174/

For eg: there\'s an EOI for some 740cca batteries - less than $100!

[boon]

 QRAF said:

yeah i\'ve heard newer soundstream aren\'t the best amps as there getting made cheaply, thats why i thought i\'d buy an old 2nd hand one yeah its only $450 so pretty keen

Go buy one of the Jaycar 1000wrms Class D amps for $375 new, sure it\'s not 2600wrms but it\'s a well-made amp with a warranty.

[QRAF]

go to know are they bridgeable?

[boon]

 QRAF said:

go to know are they bridgeable?

Depends what you mean by bridgeable, as that\'s usually used to say combining 2 channels of a stereo amp into 1.

They can be "strapped" with a second identical amp to do 2000wrms into 2 ohms, and knowing these amps I would say you could carefully run 2 of them into a 1 ohm load for a total of about 2500wrms for a short period.

[Kiwi_Fozze]

BIG farad rating capacitors can help with battery issues. think of the cap as a surge tank...

think you can get 10 farad capacitors, which is insane, you could spot weld with those.....

[mattapo]

you have to watch the cheap amps, they will kill good gear, I see it the whole time, good subs, cheap amp, "Jaycar, sound magnus e.t.c"

one thing to look out for is the THD specs

Total Harmonic Distortion (THD) @ RMS Output: 0.01%

THD at 4Ohm load 30% Rated Power:<0.3%

The second is a cheap amp is distorting more at 30% output than a good one at max rated output!!!!

If you want a mean deal, Its the same as I am running, very efficient, Im not running a cap (Granted I do run stock twin batteries).

http://www.trademe.co.nz/motors/car-stereos/amplifiers/mono-1-channel/auction-695651596.htm

If you want a good battery I\'ll hook you up on a optima.

you want to try and keep away from running your gear at 1Ohm, Im planning on running at 8Ohm

[lachlan]

u are a mad shunt

also coz ur link is broke

http://www.trademe.co.nz/motors/car-stereos/amplifiers/mono-1-channel/auction-695651596.htm

[mattapo]

it was to, fixed, now there is two working Links, Crazy!!!!

[boon]

 Trends Car Audio & Alarms - Mattapo said:

you have to watch the cheap amps, they will kill good gear, I see it the whole time, good subs, cheap amp, "Jaycar, sound magnus e.t.c"

one thing to look out for is the THD specs

Total Harmonic Distortion (THD) @ RMS Output: 0.01%

THD at 4Ohm load 30% Rated Power:<0.3%

The second is a cheap amp is distorting more at 30% output than a good one at max rated output!!!!

If you want a mean deal, Its the same as I am running, very efficient, Im not running a cap (Granted I do run stock twin batteries).

http://www.trademe.co.nz/motors/car-stereos/amplifiers/mono-1-channel/auction-695651596.htm

If you want a good battery I\'ll hook you up on a optima.

you want to try and keep away from running your gear at 1Ohm, Im planning on running at 8Ohm

I know you work in this area but I\'m going to have to disagree with you on a couple of things here...

The first being the old, flat Jaycar "Response" amps. They are in a different ballpark to SoundMagus and that crap. They come out of the same amp manufacturer in Korea (Zenon) as:

E-Audio

RE Audio

Sundown

Atomic

And a heap of other reputable brands.

The 1000w amps are, internally, virtually identical to an E-Audio 1000D. People nay-sayed this when I first brought it up around nzice until you sit there with the board from each in front of you, and they have the identical driver boards, both with the same ICs with the tops sanded off to stop the chinese factories copying the design.

Just like their 4x80 amp is identical to an E-Audio 480AB. The 2x150 and 4x100 Class D are both tough as nails.

The new, squarer amps I have no idea where they come from.

And as for 1 ohm, what\'s wrong with running gear at 1 ohm if the amp is stable down there?

If your setup will give you 8 ohms I figure it\'s gonna be a D4 or 2 D2 subs setup, why not run 2 ohms and get way, way more power? Sure the Qes is a little different, you get a little more cone control at higher Z and the amp runs a bit more efficiently but the difference in power is berserk. Considering that amp on Trademe makes 3.5kw into 2 ohms but probably makes 1500wrms tops into 8, why bother with such a big amp?

[mattapo]

I\'m planning on 8, If it works, clarity and control, its right on the limit though so may end up at 2,

At 8 Ohms the amp would just cruse, hardly get hot but will be wound rite up.

As for the Jaycar amps I have not personally had much to do with them, however I would not go there myself, I have to be able to back up products I work with if that makes sense,

Funny story, supposedly fusion come out of the same factory as sound magnus, I haven\'t looked much into it however.

1 ohm is close to a dead short, While It may run down that low I have seen plenty of 1Ohm Stable amps die with constant use, comp use e.t.c fine, crank as much as you can, but think about it as a sub moves the Ohm\'s change, a 4 Ohm sub may vary between 2 to 6 Ohms, where do you expect 1Ohm load to go.

[boon]

You\'ll never drop below the DC resistance of the voice coil, only rise above it.

1 ohm stable amps die when people mash them into clipping by sticking the gain through the roof. Amps get real sad when you try to make them output pulsed DC instead of an AC wave

[QRAF]

so bought a sub even tho nothing was wrong with the one i had now i really need to buy a new amp as the 2nd hand one is 1200wrms

[boon]

What\'s wrong with 1200wrms?

1200wrms would bag me 140dB all day long, and that\'s really, really loud. Relatively speaking at least.

[QRAF]

Digital Designs DD-3512e-2 12" sub RRP $1295

for $181 on trademe just have to sort out postage

my old one was a pioneer 800w

[boon]

 QRAF said:

Digital Designs DD-3512e-2 12" sub RRP $1295

for $181 on trademe just have to sort out postage

my old one was a pioneer 800w

That\'s a bloody good price for a 3512.

They love about 1000wrms. 1.8 cubic feet tuned to 40hz. 24 square inches of port. (Why does the audio world still run in inches???) Will go stupidly hard.

If you put it in a prefab sealed box I will swear most profusely as it is sacrilege of the highest order.

[QRAF]

lol so no putting it in a fusion box

[boon]

 QRAF said:

lol so no putting it in a fusion box

No, it will sound like anus in a sealed box, the DDs are extremely stiff subs and need a ported box in order to actually get some meaningful excursion going on.

[QRAF]

so not just as easy as drilling a hole in the said box

[Guest]

 boon']

[quote name='QRAF said:

lol so no putting it in a fusion box

/quote]

No, it will sound like anus in a sealed box, the DDs are extremely stiff subs and need a ported box in order to actually get some meaningful excursion going on.

So basically my sony 600w amp/1200w max sub in standard repco style box isnt a great setup lulz. Sounds are complex? Ive always thought a respectable set of 6\'s, 6x9\'s and a 12" sub did the trick nicely.

[boon]

 QRAF said:

so not just as easy as drilling a hole in the said box

Eeek, no. Definitely no. So much no.

You know the Car Crimes thread on here? I\'ve seen threads like that on audio forums dedicated to boxes with a hole cut in them to be the "port"