Help with Pro Amp (subwoofer) purchase.

Discussion in 'Home Theater Projects' started by Mike Keith, Dec 15, 2003.

  1. Mike Keith

    Mike Keith Second Unit

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    I am about to add another Malestrom Sono sub to my system and I’m short on Power, or Current should I say, these subs don’t need much power to get them going and my existing amp will already bottom the driver out if I’m not careful (400W mono).

    I could use some help deciding which Pro AMP to use, I seriously thought (and still am) about buying another Audio Source Amp3 as I already have one running on my single Maelstrom Sub with both voice coils paralleled. I’m a little worried about this amp handling a near 2 ohm load for the long haul, as it is not rated for this kind of use, but if I buy another ($400) Amp 3 then I could use one amp on each Maelstrom sub and one channel per voice coil which would be 150W per voice coil.

    The other option is just to buy a good Pro 2-ch amp that will handle the 2ohm load, so here are my choices.

    QSC PLX 1602
    QSC RMX-1450
    Crown CE2000

    I’m not sure which would be best the PLX is $200 more than the RMX for approximately the same power, is it that much better? I know nothing about the Crown CE series compared to the QSC, any thoughts? I'm a little worried about noise on these Pro Amps can anyone help with first hand experience?

    I can get wholesale prices on all the amps at Parts Express so I will probably buy there.

    Thanks.
    Mike
     
  2. Allen Ross

    Allen Ross Supporting Actor

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    Crown DC300 A II

    It will take it like a champ, and you will own a piece of audio history. How could you go wrong?
     
  3. Mike Keith

    Mike Keith Second Unit

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    A friend of mine had 2-DC300's and I was very unimpressed with the Thin and extremely noisy sound, no offense but this the very reason I'm leery about Pro Amps.

    Either the technology has come a long way and Pro Amps are much better now (better bottom end and higher S/N and no hum or thump) or everybody using them forgot what a good quality home audio amp could sound like for a sub amp. I’m trying to avoid some serious buyers remorse here.

    I hope that the former is true, as Pro amps offer a far better value in the Watts per dollar category, which again raises a red flag; why are they so cheep?

    Since I've never owned a Pro Amp and only heard some old Crown DC300's which I didn't like, I was hoping to lean on the experience of some hear who have heard some of the newer QSC and Crown value priced amps.

    Thanks for the reply though, it seems like nobody else has any good advise.
     
  4. JimPeitersen

    JimPeitersen Second Unit

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    Mike,
    You are correct in your assumption that pro amps have come a long way since the 1970's. The old Crown amps were solid, but they simply don't offer the power/features of today's new offerings (no slight intended to DC-300 owners!) You will find that many of the new "pro" can compete with good "home" amps (power, features, power draw, etc.) I think that you will be pleasantly surprised to hear the QSC (RMX, PLX), Crown (Micro/MacroTech, CE), Crest (CA, XS), Stewart (CA, World), Behringer (Europower), and Yamaha (P series II) lines.
    JP
     
  5. Allen Ross

    Allen Ross Supporting Actor

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    what are you talking about, the DC 300 was stated at the single best solid state stereo amp,

    I have to say I have absolutely no complaints from it what so ever, it has amazing low end and crystal clean sound. I would rate it above my Onkyo DD receiver. My guess is is wasn't feed a proper signal.

    Read some of the documentation on the DC300, and look at the research and tests that they have done on it. It has amazing signal to noise ratio, 110 db, and has no thump, or hum.

    Also try and find a new pro amp that doesn't have a fan.

    As for power, granted it won't power a tumult but give it a speaker with a half decent sensitivity it will kick some ass.
     
  6. Robert_Gaither

    Robert_Gaither Screenwriter

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    The amp 3 will survive but as a precaution I'd advise replacing the slow blow fuses with some fast blows to help protect the amp a little bit (I ran my amp 1 bridged for 2 years into a 2 ohm load and it's still going strong). I'd still recommend a pro-amp though as for a slight more price, you'll get twice the power easily (I also have a QSC RMX1450, slight difference in headroom).
     
  7. Mike Keith

    Mike Keith Second Unit

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    Well I didn't get enough responses in time, so I pulled the trigger on a Mackie M 1400i which will give me 700W per ch @ 2 ohm load, plus the input sensitivity can be adjusted and there is a neat variable low cut filter that I could use.

    I don't know anything about Mackie but at $540 I thought I'd give it a try, hope the fan isn’t too loud.

    http://www.mackie.com/products/m1400/index.html
     
  8. Dan Hine

    Dan Hine Screenwriter

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  9. Allen Ross

    Allen Ross Supporting Actor

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    that still has good quality, ie isn't class D.
     
  10. Brian Bunge

    Brian Bunge Producer

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    Allen,

    I assume you do not consider the K series amps high quality? I know many that would be in total disagreement with you; including myself.

    Oh, and I'm sorry, but it is not a class D amp. According to Crown, it's a Class I amp (Balanced Current Amplifier). This topology is used not only in the K series amps, but also in the CE 4000, CTs 2000 and CTs 3000 amps.
     
  11. Allen Ross

    Allen Ross Supporting Actor

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    As a PA amp, sure it kicks ass, puts out huge wattage at any impedance, but that wattage is also rated at .1% THD. Its built for Clubs and Gigs, where I believe the the quality of the isn't the biggest factor, a sort of brut force method.
     
  12. Brian Bunge

    Brian Bunge Producer

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    The K series are studio quality amps. I know someone that has done some A/B comparisons using his K2 and a high end "audiophile" amp with a pair of $5K+ monitors and said that he'd have absolutely no problems running a K2 for his mains full time.
     
  13. JimPeitersen

    JimPeitersen Second Unit

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    Mike,
    Sorry this thread seems "hi-jacked," but it is a good discussion concerning pro amps.
    Allen,
    I know that you are proud of your DC-300 purchase (as you have noted on numerous occasions), but you can certainly understand my suggestions (along with others) that Mike look into any number of modern pro amps that would meet his criteria. Just because people don't recommend the DC-300 to others inquiring about a pro "sub" amp doesn't mean that it is a "bad" amp, nor should you take offense to statements that suggest that modern pro amps (as a whole) are much better than the offerings of the 1970's and 80's.
    JP
     
  14. Allen Ross

    Allen Ross Supporting Actor

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    true, going over what was posted and what i posted, i can def see that i came off as an ass.
     
  15. Ellen

    Ellen Stunt Coordinator

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    Real Name:
    Ellen
     
  16. Mike Keith

    Mike Keith Second Unit

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    Thanks for the input Ellen,

    I was afraid that the fan would be a problem, looks like I'll probably have to change the fan out if I keep the amp. BTW what are your impressions of the Mackie 1400, do you like, is it clean sounding and does it match up well to typical HT preamp output voltage?

    Also someone else mentioned high distortion on Pro amps, however according to the research I have done, at least in the specifications I noticed nearly all the major brand Pro amps are rated at .05 or lower THD, the Mackie shows .025 in some configurations. In addition, I don’t believe that distortion should be a real problem even up to 2% at very low frequencies, I could be wrong.
     
  17. Ellen

    Ellen Stunt Coordinator

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    Mike, I sent some comments to you via email. I also finally managed to get the fan out of the 1400. It is a Panaflo FBA08A24H which is 24VDC, 39.6 CFM, 32.0 dB-A. Unfortunately the fan I had to replace it is only 12VDC, so I'll be looking for a different one.
     
  18. Mike Keith

    Mike Keith Second Unit

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    Thanks Ellen, I got your e-mail just haven’t had time to reply, still working on my sub project every spare minute.

    Thanks for the heads up on the Mackie amp fan, I should have mine today so I'll see just how loud the fan is, although I still have hope as mine is a 1400i which is a bit newer than the 1400.
     
  19. Ellen

    Ellen Stunt Coordinator

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    Mike, the only difference between the 1400 and the 1400i is the Speakon connectors on the 1400 which are absent from the 1400i. I have the 1400i.
     
  20. Mike Keith

    Mike Keith Second Unit

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    Thanks for dashing my last hope LOL.

    Anyway the Amp is waiting at my door according to the tracking so I'll try a few things, if it's still too loud then I will replace the fan, I have several in stock where I work of all voltages and I'm quite used to dismantling electronics so it should not pose a problem.

    Thanks Again.
     

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