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Discussion Starter · #1 ·
Crunch PZA1600.4

4-Channel Power Zone Series Amplifier
MAXX Power Rating:
4 ohms: 200 watts x 4 chan.
2 ohms: 400 watts x 4 chan.
Bridged, 4 ohms: 800 watts x 2 chan.
Not CEA certified

MB Quart Onx4.80

ONYX Series 4-Channel Class A/B Car Amplifier
RMS Power Rating:
4 ohms: 80 watts x 4 chan.
2 ohms: 160 watts x 4 chan.
Bridged, 4 ohms: 320 watts x 2 chan.
CEA certified


I'm looking to power 2 component speakers up front (JBL ms-52c, 80 watts RMS each) and an Arc12d2 sub (350 watts RMS).

How many watts does the Crunch PZA1600.4 really put out? My guess is half of what is advertised, is that a good assumption, or is it more like 75%?

I know the MB Quart Onx4.80 will put out its advertised power, but even at its maximum output, it won't fully power my sub woofer. Would the Crunch amp have more power than the MB Quart amp and would it be able to "overpower" my sub?
 

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I am not a big fan of MB Quart, but I don't see any reason to pick Crunch over MB Quart. Just look at fuse sizes.

Crunch: 2x25amps
MB Quart: 2x30amps

These probably have about the same efficiency, both being cheap Class A/B amps. Not only Crunch is almost certainly less powerful than MB Quart, but I also wouldn't be surprised if MB Quart does it bit over its own factory rating.

Nonetheless, I am personally not a fan of using a relatively compact Class A/B amplifier to power mids AND subwoofer because of heat issues. I have a relatively compact MB Quart REF4.80 amplifier (2x35amp fuses) powering a set of 4ohm woofers and 4ohm tweeters (!!!) and it can run stupid hot on a hot summer day. Here in Texas there are usually a couple of months when every metal object in the trunk will get very warm simply from car being parked under sun, though this amp also showed signs of discomfort in cold weather but when air flow was sufficiently obstructed around it. If you bridged a couple of channels for subwoofer, not only they'd have to potentially provide a lot of power, but they will also be seeing 2ohm load individually, which would make the amp even less efficient.

My recommendation is to get a dedicated Class D amplifier for a subwoofer. My pick would be PPI Phantom P600.2. Or perhaps a relatively high power 4-channel Class D amplifier, such a PPI Phantom P900.4 (or their Soundstream Tarantula or NVX copies), to power a sub and speakers. These are proven performers. They may indeed cost a bit more than MB Quart ONX, but you have to agree that usually there is no free lunch IMO.
 

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Discussion Starter · #5 ·
I've heard that class D amps are only good for low frequencies and subs and not high frequencies that speakers put out. I might also consider this amp for my setup: MB Quart Onx4.125, which does 125 watts rms x 4 channels, and bridged does 500 watts rms x 2 channels.

The only thing about that amp is that it is really big (20x9 inches).
 

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You won't hear any difference between the classes unless it's a sonic signature of the amp (bad) or poorly built (bad). I wouldn't worry about it. There are plenty other amps to use besides those and not all A/B amps will have heat issues. The Onyx series are noted to have that issue so I would choose something else of known quality regardless of class like JBL, Pioneer, etc.
 

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Class D amps can play high frequencies just fine if they are designed to. Sub amps won't because there typically designed to play up to 200hz or so but the JL HD series for instance has no problem playing up high and is considered by many to be great for SQ.

I've got that 125x4 onyx and haven't had heat issues with it but it is only powering my mids and tweets (both 4ohm). The only time that ive had it heat up is when i play my system full tilt in 90-100 degree weather and its never gotten so hot that i couldnt keep my hand on it indefinitely. I use the five second rule with electronics, if you can't touch it for five seconds then it's too hot. And yea, it's not exactly small, it's bigger than my 1200watt sub amp.

Lots of people run a sub off a 4channel, and it seems to work just fine, though I do prefer to run a separate amp.

Edit: forgot to add that my amp rack is hanging upside down from the rear deck so it's not exactly great for cooling.
 

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Discussion Starter · #8 ·
Class D amps can play high frequencies just fine if they are designed to. Sub amps won't because there typically designed to play up to 200hz or so but the JL HD series for instance has no problem playing up high and is considered by many to be great for SQ.

I've got that 125x4 onyx and haven't had heat issues with it but it is only powering my mids and tweets (both 4ohm). The only time that ive had it heat up is when i play my system full tilt in 90-100 degree weather and its never gotten so hot that i couldnt keep my hand on it indefinitely. I use the five second rule with electronics, if you can't touch it for five seconds then it's too hot. And yea, it's not exactly small, it's bigger than my 1200watt sub amp.

Lots of people run a sub off a 4channel, and it seems to work just fine, though I do prefer to run a separate amp.
Where did you mount that onx4.125 amp? In my 2001 civic, i don't know where i should mount it if i get it.
 

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Also my amp rack is shaped like this:
|-----------|
| AMP |

I had intended to add fans to blow along the fins like this:
|-----------|
| xAMPx |
-- --
But I just never got around to it because neither amp gets hot enough to justify the effort
 

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Neither, havent heard any positive comments on the mb. Crunch has made a few quality amps over the years but thats not one of them.

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Discussion Starter · #11 ·
Neither, havent heard any positive comments on the mb. Crunch has made a few quality amps over the years but thats not one of them.

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Actually, quite a few people have good things to say about the mb quart onx amps. Just look at the reviews on sonicelectronix
 

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Actually, quite a few people have good things to say about the mb quart onx amps. Just look at the reviews on sonicelectronix
Honestly I wouldn't base my decision on those reviews. The users knowledge and experience level is completely unknown. Maxxsonics has slowly destroyed the mb name. The last mb line that was up to par was the discus series. Its been discussed that the onyx line is of low quality and just doesn't last. I would go hifonics before I went the mb onyx route. Theres a lot of threads on caco about the lack of quality associated with the onyx line.

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Discussion Starter · #13 ·
Which Hifonics amps would you suggest for a pair of 80watt rms speakers and a sub rated at 350watts rms? I was looking at the Hifonics Zeus line, particularly the ZRX1000.4. Are these amps CEA compliant (do they put out their advertised power?)
 

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Whats your budget? You mentioned the ppi 900.4 I run my whole setup on two of them. Absolutely love them. If you didn't want to spend that much there are cheaper alternatives.

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Discussion Starter · #15 ·
Whats your budget? You mentioned the ppi 900.4 I run my whole setup on two of them. Absolutely love them. If you didn't want to spend that much there are cheaper alternatives.

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I would like to go as cheap as possible without sacrificing sound quality or reliability, but I don't want to spend a lot just to have the best possible amp out there. I just want something that will get the job done, not half-assed though, I want it to be able to do the job right.

I didn't mention the p900.4, someone else did. I looked at them and they seem ok, but wouldn't they overpower my 2 front speakers (rated @ 80 watts rms) too much? The amp is perfect for my 350 watt rms sub, but i don't know about the speakers...
 

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How do you feel about buying used? Trumpet has a 900.4 for sale think its $180 shipped. Theres a couple mb discus 4125 on sale on caco for $115. I know you don't want to spend much but imo buying a used decent amp will carry you a lot further plus they'll carry a higher resale also. Don't worry about the power just watch your gains

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Discussion Starter · #18 ·
How do you feel about buying used? Trumpet has a 900.4 for sale think its $180 shipped. Theres a couple mb discus 4125 on sale on caco for $115. I know you don't want to spend much but imo buying a used decent amp will carry you a lot further plus they'll carry a higher resale also. Don't worry about the power just watch your gains

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I'll buy used if I know I'm getting a legit product that works well. How do the gains work on the PPI 900.4? If I were to turn down the gain to match my sub's output at 350 watts rms, it would still be putting out like 113 watts to my two 80 watt rms speakers. Wouldn't that be too much for them?

And I like the MB quart discus 4125 but they are just so big. What do you think of the Hifonics Zeus zrx1000.4? Do they put out their advertised power?
 

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All of the Onx amps put out more than their rated power by at least 10% in 4 ohms, not sure about other loads. I have an onx 4.80 in my G35 running 4 x 4 ohms and have been very impressed by this amp. If hung upside down I could see heating problems though, just make a rack with a fan. All amps besides class D will have heating problems upside down for sure that would limit the life of the amp. Class D amps are great amps also, I never used one for mid/highs but I have for subs and it was flawless (Rockford Fosgate R250-1D).
 
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