Need some AMP advice

[Ru Dawg]

Ok, I really would like some advice on choosing an amp for a 10" Infinity Kappa Perfect woofer (350watts max rms @ 4 ohms) enclosed in a Q-Logic custom (the one in the cargo net area). I've narrowed it down to 4 amps. Please tell me what ya think and why! The Watts RMS listed are the bridged rating.

1. Crunch P-280: THD- .05%, 320W RMS, Signal-to Noise 90db.

2. MTX Thunder 6152: THD- <0.1%, 325W RMS, Sig-to Noise >110db

3. Power Acoustics Farenheit Q2-540: THD- .02%, 330w, Sig-to-Noise 97db

4. Profile Clarus CL400: THD- .07%, 300W, Sig-to-Noise 105db

I'm starting to lean toward the MTX since it has the highest sig to noise ratio since a THD of anything less than .1 is inaudible....what do ya think please???

 

[leenjen]

MTX is probably the best amp manufacturer out of the four choices, but the model you listed (thunder 6152) doesn't put out 325w rms, it only does 150watts rms @4ohm mono. so the MTX is out, unless you go for the thunder 8302 (300wX1@4ohms). that would be better than the others. the only other amp that i would buy out of your choices is the profile amp. it is another good amp. it's a lot cheaper than the MTX and will provide plenty of power for your 10" sub.

 

[Ru Dawg]

Hey thanks a bunch man... sounddomain.com has the MTX @ 325w, guess i should've looked closer....crutchfield says 150 like you did...

I was looking hard at the Profile at first but I read on the Sounddomain forum that they are overrated for power and aren't so good.....

Any better solutions for a good amp less than around $250.00???

 

[DocVijay]

One tip.

One thing to look for in buying any amplifier is to check the amperage of fuse on the amplifier. That will give some idea of what kind of power the amplifier will really put out. Those cheap flea market amplifiers (no offense to anyone that has one) that say 1000 watts!!!!! are full of crap, for on the side is a 20 amp fuse. Physics says it's impossible. There are also amps that say 50 watts, yet they have a 40 amp fuse. Those are the really expensive ones that are stable down to a half ohm or something and will end up putting out a massive amount of power. So just keep that in mind. Most of the ampslifiers you listed a pretty decent, so shouldn't really be an issue.

 

[JTang]

You're not wrong, you just misread. The MTX can put out over 300 watts RMS, but only at 14.4 volts which are cars are not. I think the toss up between the MTX and Profile is pretty close. You have MTX that underrates their amps and Profile which overrates their amps (just by a little in each case).

I have two of the first MTX Thunder series amps, the 2300s, and I bought them used for $200 each. I bought them both off younger guys with fixed up cars, so I know they were pushed to their limits, but I've never had any problems with them ever. If you can find a strong, brand name amp used, I wouldn't discount that option either.

 

[Ru Dawg]

Ok...everything ya'll said adds up and makes sense...but I just went out and check my DC voltage w/ a fluke. I get 14.45 volts DC everywhere I check. So wouldn't I want the MTX 6152, which is rated to 325W @ 14.5. I went to MTX's site and check it out. They rate their amps at the conservative 12.5volts and also give the 14.5 volt rating. The 8302 is rated at 300w @ 12.5 volts and 425w @ 14.5 volts...so that would be too big for a 350w sub...correct?

Please don't get frustrated w/me...I think I'm settled on MTX...I just want the right one and I don't want to over OR under power my woofer man!!! I really just want to get the most out of having only 1 10" sub....don't want to loose cargo space!!!

Thanks again!!!

 

[leenjen]

th mtx is the best out of the amps you chose, but maybe you should get a capacitor to keep the voltage up. you dont have to, but the voltage will definitely drop during deep bass. just a suggestion. so go for the thunder 6152, but you might want to look into a capacitor since they're not very expensive and do a lot for a system.

 

[TerraBomb]

i didn't have an cap for the first 2 weeks and i regretted it pretty bad, they don;'t only keep your voltage up but also keep the bass going.

the setup i now use (i haven't updated my sig yet..heh ) is an 2 fahrad cap....

before i had the cap i would see my voltage dro pto under 12 volts wich is not healthy , plus it makes the lights dim really bad...

in your case an 1 fahrad would prolly do just fine...but an 2 fahrad can never hurt....

 

[Ru Dawg]

Good thought T-bomb...I was actually planning on it. But I don't think I will need a whole Farad for my setup. A .5 farad should do fine. The rule of thumb is .5 farads for every 500watts Rms.

I think I'll either get the MTX 6152 or the Profile...not sure if I wanna spend the extra cash on the MTX, and the Profile actually looks better if you ask me (not the most important thing of course).

Anyone know a good place to buy a MTX for cheaper than sounddomain or crutchfield..they both list $249??

 

[sideswipe]

Question about caps guys---

If I have a 600W amp for my highs and an 800W amp for my lows (bass), how many caps do I need? And how many Farad should I get ?? Thanks in advance....

Also, how hard is it to add a cap to my current setup? Which cap is best?

 

[cjyoung77]

Absolutely MTX

I would say definately go with the MTX even if you do have to pay a little extra. I had a couple of their old amps from back in the day and they sucked, but I think it was about 4 or 5 years ago MTX recruited a bunch of engineers who really started MTX building excellent amps. I have four different ones powering my component set-up and subs. with the right capacitor these things are great.
RuDawg, you are right about the looks though, I have seen much better looking amps out there just not better performing ( except for alpine's V series amp, the only thing from alpine I would have these days) hope this helps.

p.s. oh yeah, TerraBomb that box is the ****! Did you custon that yourself? That is exactly the design that I had envisioned using. What did you make it out of? Hope you don't mind, but I am definately gonna have to steal some design ideas from your box!

 

[Ru Dawg]

Well thanks again guys. Though after all the trouble I think I'm gonna forget the Q-Logic thing and get the MTX Amplified 10" Thunderform...did some research and it seems pretty decent. I'll still add a 0.5 farad cap. I think this will be enough for my needs. I don't want a super bass machine...just wanna fill that big open space with some good sound!!! I'm sure the T-form will be enough..if not I'll just return it and go back to plan A !!!

 

[leenjen]

Originally posted by sideswipe
Question about caps guys---

If I have a 600W amp for my highs and an 800W amp for my lows (bass), how many caps do I need? And how many Farad should I get ?? Thanks in advance....

Also, how hard is it to add a cap to my current setup? Which cap is best?

you will only need a capacitor for your bass amp. get a GOOD 1 farad cap (stay away from the 16volt with 20 volt surge). i use audiobahn because all their caps are 24volt with 28volt surge.
a 1-farad cap will be fine (if it's a good one). all you have to do is charge it to your alternator's output (some charge automatically).
it only takes a few minutes.

 

[sideswipe]

OK, so the Rockford cap (16v, 20 surge) is no good right? Is $100.00 a good price for the Audiobahn cap?

 

[leenjen]

i wouldnt say it's no good (it's an improvement compared to nothing at all), but not a very good cap. $100 for the audiobahn sounds about right.

 

[JTang]

I would still say go with the MTX amp if you had to choose an amp (though you're getting the Thunderform). It may have more power than you need, but that doesn't mean you have to play the amp to the max. If you took it easy on the sub, it would be okay. Plus, I believe the sub you're set on can take a pretty mean beating too.

In addition to the MTX trivia, they stole engineers from Rockford Fosgate, I believe - Just when MTX came out with their Thunder series that put them on the map as serious manufacturers, and Rockford Fosgate started to lose it and make lesser amps to sell at Best Buy.

 

[leenjen]

Originally posted by JTang
In addition to the MTX trivia, they stole engineers from Rockford Fosgate, I believe - Just when MTX came out with their Thunder series that put them on the map as serious manufacturers, and Rockford Fosgate started to lose it and make lesser amps to sell at Best Buy.

thats exactly right.
as a matter of fact, the new rockford fosgate subs aren't so hot.
they have a lot of problems with burnt voice coils and exaggerated power handling. they have been using cheaper materials and producing lower quality products. it's really a shame.