strapping amps

[myvanpounds 10+ year member]

guys I have a couple of questions about strapping amps. first is how do you do it, second are all amps strappable, and third what does it do to the power ratings? I have two autotex xs900.2s and I'm thinking about running 2 SI mag D2s but my amps are only 2 ohm stabble @ 900 watts

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[squeak9798 5,000+ posts]

first is how do you do it,

Typically you connect the (+) speaker output from one amp to the (+) terminal on the speaker and connect the (+) speaker output from the 2nd amp to the (-) terminal on the speaker. Then you connect the two still unused negative amplifier terminals (one on each amp) directly to each other.

Kicker has a diagram in their owner's manual for the KX series amplifiers (on page 6):

http://akamaipix.crutchfield.com/Manuals/206/2064KX1200.PDF

RF has a diagram aswell on page 10 of this manual:

http://www.rockfordfosgate.com/scripts/rightnow.cfg/php.exe/enduser/fattach_get.php?p_sid=5Z1Sbxbi&p_tbl=9&p_id=301&p_created=1083264150

second are all amps strappable,

No

and third what does it do to the power ratings?

It's very similar to bridging a 2-channel amplifier. Power output is the combination of the two strapped amplifiers, but the minimum impedance the strapped pair can drive is double their individual lowest rated impedance since each amplifier will "see" half of the load.

For example, if you have two strappable amplifiers that individually produce 1200w @ 1ohm, then you can not strap them into a load lower than 2ohms (double their individually rated minimum impedance, since each amplifier would "see" half the load), and when driving a 2ohm load they would output a total of 2400w (the combination of their individual power output @ 1ohm). Since each amplifier "sees" half the load, in this case 2ohms total, then each amplifier would output 1200w since each amplifier is "seeing" a 1ohm load and they will therefore output their 1ohm rated power.

So if you have two amps that are not stable below 2ohms, then you can not strap them to a load lower than 4ohms.

Clear as mud?

 

[Showrides]

guys I have a couple of questions about strapping amps. first is how do you do it, second are all amps strappable, and third what does it do to the power ratings? I have two autotex xs900.2s and I'm thinking about running 2 SI mag D2s but my amps are only 2 ohm stabble @ 900 watts

Why don't you just wire each mag to 4 ohms. They will still sound great, and get very loud with as little as a few hundred watts.

 

[myvanpounds 10+ year member]

ok so now what makes an amp strappable

 

[myvanpounds 10+ year member]

Why don't you just wire each mag to 4 ohms. They will still sound great, and get very loud with as little as a few hundred watts.

cause 1800 > 1400

Basically I'm not happy with the fact tha I have to run two amps and waste 20 cubes for a single 18 when I could be running sat two 15s ported

 

[btnhfan 5,000+ posts]

No

Technically, I belive thats incorrect.

But im pretty sure theres ways to "strap" almost every amp.

I remember reading a thread on it by RC on carsound.

 

[squeak9798 5,000+ posts]

Technically, I belive thats incorrect.

But im pretty sure theres ways to "strap" almost every amp.

I remember reading a thread on it by RC on carsound.

Rephrase:

Not all amps are recommended by the manufacturer to be capable of strapping.

Happy now Mr. Nitpicker //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif//content.invisioncic.com/y282845/emoticons/moon.gif.9d317aec3339ffe7fde0638df52c628a.gif

 

[btnhfan 5,000+ posts]

Yayyyyyyy!

Ha but your right though.

For all intensive purposes you really dont need to strap amps anyway.

Especially ones that dont have its setup from the manu.

For pretty much

 

[thch 10+ year member]

it is in theory possible to wire as many amps as desired in series, so long as there is galvanic isolation. basically +5V on amp1 must not have any set relation to +5V on amp2.

one way to ensure this is to use transformers on the outputs of each amp. this allows the output of the amp to appear at the transformer secondary, and yet not be connected to the amp's power supply.

its similar to having multiple batteries. you can't wire them in series if all batteries have their - terminal attached to the chassis!

for two amps, the amps can be concidered strappable if each has a single-ended output that can switch between inverting and non-inverting. i haven't seen any amps that advertise that an arbitrary number of amps can be used, so i assume this is what is done. its effectively the same thing that bridgeable amps do. one amp puts out +V, the other -V. the difference between +V and -V will be +2V (or -2V).