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Any experience with the Crest CA4, Carvin HD900, or similar?

Discussion in 'Amps and Cabs [BG]' started by bongomania, Dec 5, 2006.


  1. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Lots of folks on here rave about the CA9, talking about the massive punchy sound. I only need about 800W or so (@4ohms bridged), and I'd like to not have such a boat anchor as the CA9.

    I notice the CA4 fits the power requirement, but it's the same size as the 2,000W CA9 (18" deep), and only 6 lbs lighter.

    Anyone know if the Carvin HD900 /HD1800 power amps use the same design of power section as the B1500 that's so popular here? The HD models claim to have massive toroid supplies, and they're both a lot smaller and lighter than the CA4... but what do they lose along with the size and weight?

    So: Anyone here with hands-on experience with either of these units care to give their opinion? Any other suggestions for a mighty-sounding 800 to 1,000W big-iron type (not switching) power amp that's more compact than the CA4?
    Thanx! :bassist:

    Edit: I've seen posts from a couple of guys here who own and like the HD900, but it would be awesome to specifically hear more about how those amps compare to big-name "lead sleds" like the Crest.
     
  2. Peg_legs

    Peg_legs

    Nov 19, 2005
    Huntsville, AL
    I had a CA4. It sounded great but was super heavy. I didn't get rid of it for the weight. It was kept in a rack with wheels. I traded it locally for an Eden head.

    The CA4's can be found cheap.
     
  3. MotorTed

    MotorTed

    Apr 16, 2006
    CT, USA
    I used a Carvin HD900 with a SVP-Pro Pre in this review:

    http://www.talkbass.com/forum/showthread.php?t=292502

    I didn't mention it in the review but I had the HD900 bridged and all the way up and the master on the pre up all the way and the SVT 2Pro (300W tube) was much louder.

    I too am curious about the CA-9 that I hear so much about.
     
  4. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Cool, thanks for that info. Anyone else?
     
  5. Jeralya

    Jeralya

    Sep 7, 2006
    Chicago, IL
    I have been kind of curious on the difference between DCM and HD from the Carvin lines... anyone?
     
  6. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Don't know much about the CA-4 but I still own and use a CA-6 to light up an Acme B-4. Been through about 5 different preamps but the Crest never fails to amaze me.

    Riis
     
  7. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I'd guess that if they are both current lines (I'm sure the DCM line is because I've ordered and used a number of them) that the website or print catalog would at least hint at the differences in the specs. Perhaps the HD is a lower cost amp? If so, it's likely like anyone else's cheaper amp in that it doesn't have as good of specs as their higher priced ones.

    That doesn't mean it's bad (if in fact it is cheaper), but it's NOT AS GOOD. The DCM are pretty amazing for their price.
     
  8. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Huh- I had somehow gotten the idea that the DCM's were "switching" amps, but now I went back and checked, and they are of course advertised as having "massive toroids" like the HD's. :rolleyes: Earth to bongomania, hel-llooooo!

    Anyone compared the DCM's with the Crests?
     
  9. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    Bump because I'm wondering exactly the same thing.

    Maybe this crest CA snob will have to buy a Carvin to check out. I'll be looking at the DCMs ...

    I just realized that I've been carting around these huge stereo amps and only using one side, I'd be better off bridging a less powerful amp.
     
  10. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    Actually, most of the people that have posted about using the CA9, indicate that they use only one side (non-bridged).
    From Crest's website the CA9 is 600Wpc @ 8 Ohm and 900Wpc @ 4 Ohm (non-bridged).
    If you bridge the CA4 it has 830W @ 8 Ohm and 1100W @ 4 Ohm.

    Other than having the redundancy in case of a channel specific failure, you're getting more for less with the CA4 (I've considered this as an option myself).

    The reviews here of the DCM line and the B1500 have me seriously considering one of these as a serious option also.

    Ideally, powerwise, I'd love to get a DCM2500 and bridge it.
    That way, the amp would just be loafing along on any given gig and operating fully within its design parameters with the modest demands it would face for bass guitar reproduction.
    The only downside to me is that it's a 3U racksize.
     
  11. el_Kabong

    el_Kabong

    Jul 11, 2005
    I'm not sure that's entirely true. I suspect most of that 6lb difference is in the power supply. According to the manual, the ca9 has more than 2.5 times the filter storage capacity and an 80% better slew rate. Admittedly I don't know what that adds up to in the real world because I've never used a ca4, but for the sake of 6lbs I'd stick with a ca9. ymmv of course.

    I find I don't need anything like the volume a ca9 can produce (I don't run it bridged). It's the feel and the wonderfully solid and deep bottom end that I like, not just the watts. The power supply probably has a lot to do with that.
     
  12. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    I'm talking about comparing one CA9 channel to a bridged CA4.
    Is the total CA9 capacitance used even if you're only using one channel or is it only using 50% of that 2.5x more capacity?
    If it's only 50%, that's not much of a difference.

    I've been told (by Bob Lee of QSC) that in a well designed modern power amp slew rate is no big deal (going from moderate rates to really big numbers), but I'm not an EE, so whatever...
    [Also, I believe that an amplifier's slew rate is doubled when bridging, but I could be wrong. If I'm right, then the CA4 when bridged would have a better slew rate than the CA9 non-bridged.]
     
  13. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    FWIW, I ended up buying a DCM 1000, and it sounds killer. I have not tested it at a gig (and I have no gigs immediately upcoming) but I did turn it all the way up, and was quite impressed with the tightness and clarity of the sound at high volume. Of course I should buy a CA-4/6/9 to compare, but I don't feel like I'm missing anything at this point.
     
  14. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    For 6lbs savings I would not opt for a CA4, since I KNOW a CA9 or even CA6 sounds amazing one one channel.

    I'm looking for an amp that kicks that same kind of clarity and depth at a lower bridged power point (~1.2kW), and checking in between 20 and 30 lbs. I'd never use all the power of a CA9. My cab at the moment handles 1200 watts and is 4 ohms, so that kind of rating when bridged would be perfect.

    A DCM1500 is 26 lbs, 2 rackspaces, 1500w bridged (which even if it is a generous rating should be plenty of juice), and is pure class A/B. No funny business. Sounds like it should be a great amp for my needs. I dig the speakon bridged out as well. Brand new they are $429.

    Any other options to consider? I'm also looking at the SWR stereo 800.
     
  15. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    The DCM1500 looks good to me as well -- at the moment the 2U would be better for me.
    Bridged into 8 Ohm, it's still 1000W -- I think that would keep my 3x10 whomping along fine.
    I have a gig in a couple of weeks, so I'll have an idea after that, if I'll need more power than I currently have or not.
     
  16. Michael Vee

    Michael Vee Supporting Member

    Feb 3, 2004
    Knoxville, TN
    I've posted very positive remarks on the DCM1500 before, so I won't belabor here.

    The DCM1500 is a compact 2RU 34 pound amp that is only 10" deep and has power and headroom for days- much more than just about any player would ever need.

    And no, Carvin doesn't exaggerate the power ratings. A number of pros and techs (do searches on Google and in TB) have put Carvin power amps on the bench and checked the output, and it's bona fide all the way.

    You put a top-notch, high-output preamp in front of a DCM1500, and run the amp into high-quality, efficient speakers, and you will pulverize about any size room.

    Evaluating on size, weight, and price, the Carvin beats the Crest CA's.
     
  17. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    Sweet. Any comments on sound quality?
     
  18. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    In an amp with a conventional power supply, the reservoir capacitors are divided up among the supply rails. I'm pretty certain the CA9 has separate supply rails for each channel, so using only channel would mean half the capacitance is unused.

    The amount of capacitance doesn't tell how much energy is stored in it; that is a function of the capacitance and the square of the voltage across it. So if a particular class H amp had, say, 100,000 µF of capacitance on a 45V rail and the same amount on a 90V rail, then the lower rail's reservoir would hold 101.25 joules (i.e., watt-seconds) of energy and the high rail would have 405 joules.

    Bridging an amp doubles its slew rate, but that's a wash because it also doubles the voltage it has to swing. But in reality, the vast majority of pro power amps (and certainly all the well-designed ones) have low-pass filtering well above 20 kHz to reduce sensitivity to RF interference, and that tends to also ensure that the amp will never have to reproduce a signal that even approaches its slew rate. Slew rate by itself is a useless spec except to marketers touting numbers to unsophisticated consumers; much more useful is power bandwidth, because it takes maximum output voltage and high frequency response into account.
     
  19. el_Kabong

    el_Kabong

    Jul 11, 2005
    Thanks for the edification Bob. I see the ca4 is also listed as class A/B and the ca6/9 as class H. Any comments about that?
     
  20. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Class H is just a higher-efficiency version of class AB. It uses two or more tiers of supply rail voltages, with automatic commutation between them. Normal audio program, like music, is usually well below maximum output most of the time, so it makes sense to run the output transistors on lower supply voltages, so they waste less power and dissipate less heat, and step up the rail voltages when the signal voltage reaches and exceeds the lower rail voltages.

    This allows the amp to run cooler, and it allows the user to run a high-power amp from an AC mains circuit with a lower current capacity than it would otherwise need. For example, if you can run an amp from a 15A circuit instead of needing a 20A circuit, that could be the difference between the show going on and and not going on.

    Lower-power amps like the CA4 usually don't use class H because the amount of power saved just isn't worth the added circuit complexity and parts count.
     

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