power question

[liljojo4711 10+ year member]

i am getting a mach 5 IXL 10" which is rated at 1000 wrms and i just got a planet audio bb1350.1b in the mail yesterday //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif. at 1ohm, this amp will give me 1350 wrms which i was told by the mach 5 tech that its way too much power and i should not go over 1100 wrms. how do i make sure that my amp doesnt give more than 1100 wrms at 1ohm? something to do with the gains? bass remote?

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[billjones42 10+ year member]

keep the gain way down and you'll be fine.

 

[liljojo4711 10+ year member]

how do i figure out exactly how many watts i am getting?

 

[thegreatestpenn 5,000+ posts]

I've seen the birthsheet on those amps and they usually hover around 1100wrms so I think you'll be okay. Just watch your gains

 

[CarAudioGuru 10+ year member]

Simple. Measure the AC volts out of the amplifier.

Start off with amp gains at absolute minimum (fully counter-clockwise)

Make sure your mid/tweeters are off for this part.

Put some of your ""Bass That Ate the Earth" type music on, crank the gain on your headunit up

about 2/3'rds of the way up (if it reads digitally the volume level and lets day 35 is max, turn it up to 30-32)

Now turn the input gain on your amplifier up till it distorts. If you are going to use a remote bass

control have it pre-adjusted to all the way up while you are doing this

Just make sure that the biggest number you see is NOT greater than 33 volts AC.

Hopefully a REAL DMM (like Fluke), but pretty much anything will do.

If you want to be ultra cool, do a 5dB gain overlap (harder to do as you need a O'scope)..but the REAL way to do this.

But the meter "trick" will save you a lot of issues, and it is simple.

Have fun, good luck.

We are all here to help you.

 

[liljojo4711 10+ year member]

I've seen the birthsheet on those amps and they usually hover around 1100wrms so I think you'll be okay. Just watch your gains

the birthsheet i got says 1350 at 1ohm

and where do i get a voltmeter??

 

[Pl8er 5,000+ posts]

Just do this.

Voltage of the output = sqrt(RMS Power X impedance of the speaker)

Example

Say the amp provides 100WRMS into a 4 ohm speaker:

Voltage = sqrt(100W X 4 ohms)

Voltage = sqrt(400W*ohms)

Voltage = 20V

Same as mentioned above with volume etc (2/3 of the way up) but I don't like to do it by ear (although that is not a horrible method)

 

[dman4486 5,000+ posts]

I've seen the birthsheet on those amps and they usually hover around 1100wrms so I think you'll be okay. Just watch your gains

the birthsheet i got says 1350 at 1ohm
and where do i get a voltmeter??

my BB1250.1's BS said 1251wrms@1ohm

they seem to do rated...no more no less

edit: ok...they can do less....but why would you want to

 

[dman4486 5,000+ posts]

Just do this.
Voltage of the output = sqrt(RMS Power X impedance of the speaker)

Example

Say the amp provides 100WRMS into a 4 ohm speaker:

Voltage = sqrt(100W X 4 ohms)

Voltage = sqrt(400W*ohms)

Voltage = 20V

Same as mentioned above with volume etc (2/3 of the way up) but I don't like to do it by ear (although that is not a horrible method)

^^^^^^^I agree w/ this^^^^^^^

 

[liljojo4711 10+ year member]

^^^^^^^I agree w/ this^^^^^^^

what does the 20v mean??

for my amp is would be sqrt of 1350 (1350 rms X 1ohm)

which is 36.74... what does this tell me?

 

[liljojo4711 10+ year member]

ok, i thought about it and i think i got it. i want to be under 33 volts because 33x33 is 1089 which is less than 1100 which is what im looking for. so i need to get a volt meter and make sure that when i turn my sound 2/3rds of the way up, it doesnt read more than 33 volts?

 

[dman4486 5,000+ posts]

ok, i thought about it and i think i got it. i want to be under 33 volts because 33x33 is 1089 which is less than 1100 which is what im looking for. so i need to get a volt meter and make sure that when i turn my sound 2/3rds of the way up, it doesnt read more than 33 volts?

when you get the voltage calculated, then set a dmm on VAC and turn the gain up until it reaches that number. make sure the volume is up at ~2/3 when you do this.

 

[liljojo4711 10+ year member]

got it. thanks for the help!!!

where do i get a volt meter???

 

[dman4486 5,000+ posts]

anywhere that sells electronic components......

 

[liljojo4711 10+ year member]

oh, so like best buy or circuit city