MXA3002 help car amp

[fiveabi]

Hey guys i bought a mxa3002 amp from fs on boxing day for 100.

I'm not sure if i should keep it, my concern is i want around 350watts out of it @ 2ohms for a sub, i don't know if it will supply.

Its rated at 300watts rms at 4ohms, and their "diagnostic report" inside states 386 watts rms all channels @ 2ohms.

what does this mean?

thanks.

[fiveabi]

another quick question is if a sub is underpowered by say half of its "rms" value will it be distorted?

thanks

[97'Scort]

Just from the manual, it looks like a 2-ohm load doesn't provide enough resistance for this amp when bridged. You can still try it, but I'd try sending them an e-mail first to see if they recommend it.

You may want to pick up a 4-ohm woofer instead. 300W RMS will still pound!

And yes, you want to match your sub's recommended RMS power to the amp as near as possible; you can have a little bit more power from the amp than the sub needs so you don't clip, just tone down the power a tad when you tune to the 50 Hz test signal.

[GTS Jeff]

Originally posted by 97'Scort
Just from the manual, it looks like a 2-ohm load doesn't provide enough resistance for this amp when bridged. You can still try it, but I'd try sending them an e-mail first to see if they recommend it.

You may want to pick up a 4-ohm woofer instead. 300W RMS will still pound!

And yes, you want to match your sub's recommended RMS power to the amp as near as possible; you can have a little bit more power from the amp than the sub needs so you don't clip, just tone down the power a tad when you tune to the 50 Hz test signal. Why 50Hz?

[97'Scort]

I usually set the gain on the amp (when connecting to a sub only) by running a 0-dB, 50Hz sine wave test tone. Most subwoofers get most of their "punch" in the 40-60Hz range (that's why all those bass boost knobs usually only boost a 45-50 Hz signal). Then you tune the input sensitivity of the amp until you reach a target AC voltage (important when connecting your voltmeter!) on the output of the amp.

If you want to do midrange speakers, a 1kHz test tone will work for most cases.

For a detailed explanation of the process, you can go to JL Audio's website (http://www.jlaudio.com) and download the .pdf of any amplifier manual. Near the back will be a process for tuning your amp. Some amps do not have this control, however, but you can still use the 50 Hz signal and the input gain to get a proper current.

[GTS Jeff]

Originally posted by 97'Scort
I usually set the gain on the amp (when connecting to a sub only) by running a 0-dB, 50Hz sine wave test tone. Most subwoofers get most of their "punch" in the 40-60Hz range (that's why all those bass boost knobs usually only boost a 45-50 Hz signal). Then you tune the input sensitivity of the amp until you reach a target AC voltage (important when connecting your voltmeter!) on the output of the amp.

If you want to do midrange speakers, a 1kHz test tone will work for most cases.

For a detailed explanation of the process, you can go to JL Audio's website (http://www.jlaudio.com) and download the .pdf of any amplifier manual. Near the back will be a process for tuning your amp. Some amps do not have this control, however, but you can still use the 50 Hz signal and the input gain to get a proper current. What if you tune your gains to a certain level that is perfect for 50Hz but at that same level, it clips a bit at say 30Hz?

[97'Scort]

I wouldn't imagine you'd clip at 30 Hz and even if it did, it's starting to get in the very low frequency range, so you probably won't notice too much. If you feel that 30Hz tuning would give you better response in your system, you can always give it a shot! I've never had a problem with clipping with the 50.

Part of the reason for tuning to 50 Hz is that's what's generally available unless you have something to put out exactly the frequency you want to tune to. Most tuning discs start at 50 Hz cycles.

[GTS Jeff]

Originally posted by 97'Scort
I wouldn't imagine you'd clip at 30 Hz and even if it did, it's starting to get in the very low frequency range, so you probably won't notice too much. If you feel that 30Hz tuning would give you better response in your system, you can always give it a shot! I've never had a problem with clipping with the 50.

Part of the reason for tuning to 50 Hz is that's what's generally available unless you have something to put out exactly the frequency you want to tune to. Most tuning discs start at 50 Hz cycles. The sound of clipping at 30Hz isn't what worries me, it's the fact that clipping overheats the speaker.

Anyhoo, you can download test tones from 20Hz-20KHz...

[97'Scort]

Originally posted by GTS Jeff
The sound of clipping at 30Hz isn't what worries me, it's the fact that clipping overheats the speaker.

Anyhoo, you can download test tones from 20Hz-20KHz...

Yup you bet. I've never had that problem with anything I've installed, but it's possible. I'm not really sure what the proper solution would be :dunno:

[SWX]

Originally posted by fiveabi
Hey guys i bought a mxa3002 amp from fs on boxing day for 100.

I'm not sure if i should keep it, my concern is i want around 350watts out of it @ 2ohms for a sub, i don't know if it will supply.

Its rated at 300watts rms at 4ohms, and their "diagnostic report" inside states 386 watts rms all channels @ 2ohms.

what does this mean?

thanks.
Didn't you ask the same question in another post?
The Amp is rated to run at 4 or 2 ohm stereo or 4 ohm Mono, thats it. If you want to run a sub with it you need to end up at a 4 ohm load mono.

[GTS Jeff]

Originally posted by 97'Scort


Yup you bet. I've never had that problem with anything I've installed, but it's possible. I'm not really sure what the proper solution would be :dunno: Using a million test tones and a lot of time with a dB meter I guess. :D Find the quietest frequency, tune with that, then EQ all the other bumps and lumps to something resembling a flat curve...

I dunno either...:dunno: