Crown Power Base 3 users - I have stupid questions!

Discussion in 'Amps and Cabs [BG]' started by Planet Boulder, Feb 22, 2006.

  1. Planet Boulder

    Planet Boulder Hey, this is a private Supporting Member

    Nov 10, 2001
    6,482 feet above sea level
    I once had impure thoughts. Oh, and I pluck my ear hair.
    So I currently have a Carvin FET1000 power amp being driven by an Eden Navigator. Carvins have always seemed conservative in their ratings, and this power amp, while reasonably powerful, seems to be no exception.

    I'm looking at a used Crown Power Base 3 and I'm hoping that it will be appreciably more powerful for my purposes. I know that this is subjective, but if anyone has experience with it, please chime in on your perception of its adequacy of power.

    Also, I noticed that there are no output adjustments. Does this mean that it runs full "volume" (or power) all of the time and that the volume adjustment should be made with the preamp? I've switched my philosophy to that of adjusting the master volume at the power amp level for signal-to-noise considerations and I'm guessing that I will now have to adjust the volume at the preamp output level. Is this correct?

    Apologies if these are stupid questions. Any advice/opinion on this power amp would be greatly appreciated.

    Thanks in advance!
  2. BSR6P-Bob


    Apr 5, 2005
    There are trim pots for power output on the backside.

    It's a good amp but be advised that parts support from Crown for this amp is very limited and many of these have been around the block and abused as sound company rentals.

    I had one with an Avalon U5 as a pre and the sound was nice but moved to something more streamlined.
  3. Planet Boulder

    Planet Boulder Hey, this is a private Supporting Member

    Nov 10, 2001
    6,482 feet above sea level
    I once had impure thoughts. Oh, and I pluck my ear hair.
    Thanks Bob! When you say "more streamlined", I'm assuming you mean "lighter" or more convenient?
  4. BSR6P-Bob


    Apr 5, 2005
    I went with an iAMP 600. Lighter weight, less fan noise and easier to tweak gain to my liking especially in the studio.
  5. I had a Powerbase2 and when it s##t the bed, I sent it to Crown, they said they no longer repair these models, and offered an upgrade to a new series.
  6. tadawson


    Aug 24, 2005
    Lewisville, TX
    The old joke on the PB (Power Base) Crowns was that it should have stood for "Probably Burn"

    - Tim
  7. 4runner

    4runner WARNING!"WALL OF DOOM" does "exceed" 140 decibels!

    Feb 11, 2006
    Hackensack NJ,
    Hey Planet Boulder, I just happen to use 2, Crown Power Tech 3 power amps, to drive my 8 ten's, and Acoustic 301,1x 18" folded-horn cabinet. The power base is almost the same amp as the "power tech", with subtle differences here and there. The Power base do'es have input level attenuators on each channel, but the're recessed on the rear panel of the amp, and they are adjusted with a small, pocket screw driver instead of knobs like on some other amps. The PB-3 is a great amp. It has as much power as the PT-3, can be run @ 2,4,8, and 16 ohm's,has a very low distortion ratio, and I believe it has a " input sensitivity" switch under a rear access cover for matching line levels of, 0.775 [ 0 DBu ], 1.4v, or 26DBu, to accomodate a variety of different pre-amps, or mixers. And as you probably already know Mr. Boulder, no amps handle the low end like Crown because of their high Damping factor, which is >1000 from 10- 400 Hz. The power base is a great amp.
  8. bigbajo60


    Nov 7, 2003
    Laredo, Texas
    I happen to have two PB3's that we just "retired" from PA Sub Amp duties. We installed the XLR input panel upgrade in order to make interface with the rest of our equipment a little easier. The PB series standard inputs were 1/4" jacks, one per channel. The cool thing is that the XLR and 1/4" jacks are parallel, so you can use one as an input and the other as a thru.

    While these amps are plain-jane workhorses (no bells and whistles) and kick hard, punchy bass freqs, they weigh as much as a friggin' clydesdale.:smug:

    We'll probably be selling these in a few weeks PlanetBoulder... once we're used to the new amp rig driving the PA. How much are you looking at paying for the one you're scoping out?
  9. svtb15

    svtb15 Commercial User

    Mar 22, 2004
    Austin,TX - McKinney,TX - NY,NY, - Nashville,TN
    I play it all. Whatever works for the gig
    Thread Resurrection
    does anyone know if a Powerbass 3 can run 8 ohms Parallel-Mono?
    All i see are 2 and 4ohms ratings
  10. Wasnex


    Dec 25, 2011
    I PM'ed you as well.

    You can run the PowerBase 3 parallel mono into 8 ohms but there would be no benefit of doing this.

    Here's what the manual says:
    Power Base-3
    Stereo mode (both channels driven):
    760 watts into 4 ohms.
    540 watts into 8 ohms.
    Bridge-Mono mode:
    1525 watts into 8 ohms.
    1090 watts into 16 ohms.
    Parallel-Mono mode:
    1530 watts into 2 ohms.
    1080 watts into 4 ohms.

    The above information should be used to maximize the output of the amp given the load you will push with it. Crown doesn't publish the 8 ohm parallel-mono spec because it would not make any sense to run the amp this way as you would get significantly less power than you will by running the amp in bridge mono.

    Here's the explanation:

    Crown amps are the only amps on the market that I am aware of the allow you to run either bridge mono or parallel mono. To clarify, when Crown says parallel mono they mean the inputs and the outputs of the both sides of the amp are tied together. The + of channel one is tied to the + of channel two and the - of channel one is tied to the negative of channel two. What this does is theoretically double the amount of current the amp can put out at a given voltage. This option maximizes the wattage potential of the amp into 2 and 4 ohms. Note that you actually have to put a jumper across the red terminals of the amp in addition to selecting the parallel mono mode on the back panel to make this work properly. This is explained in the manual.

    In bridge-mono mode the output of the amp is connected in series. The bridge mono switch inverts the output of one of the channels and ties the + of one channel to the negative of the other. What this does is theoretically double the amount of voltage available. It does not however increase the available current. Typically an amp that is designed to run in to 4 ohms minimum stereo will only safely push 8 ohms in bridge mono. Consistent with the specs above, this amp will run bridge mono safely at no lower than 8 amps. At that impedance it will put out 1525 watts in bridge mono.

    If you push a 4 ohm load while running this amp in bridge mono it will try to pull too much current through the output and burn it up. If you want to maximize power into a low impedance load (4 or 2 ohm) you must use parallel mono.
  11. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    i have a PB-3 languishing in my storage shed; it's a strong 700w per side @ 4Ω, but:

    it can't do 2Ω per side, which means it can't bridge into 4Ω, which means you're often stuck not being able to really "get at" all its power. (their unusual "parallel mono" option is mostly useless, unless you only have one box you're trying to power and it's 4 or 2Ω. if there's multiple boxes you might as well run stereo with one to each side of the amp, it develops the same amount of power.)

    it has no signal or clip lights, so you can't really see how it's handling what you throw at it.

    it's also heavy as balls.

    (i'm surprised crown won't fix it though; these were built more like the microtechs, i.e., "real" crowns, that were made to be fixed; it was the later CE stuff that was essentially disposable if it broke.)
  12. Wasnex


    Dec 25, 2011
    I have a PB1 and PB2. Although I prefer to have signal indicators I don't find them essential...the amp and speakers tell when they have had enough.

    Additionally, from what I have read on other forums I would not be inclined to push PowerBase amps near clipping on a continual basis. If I understand correctly, the power transformers are too small and will overheat. The size of the transformers is also why PowerBase amps are not rate for 50hz line AC.

    Regarding the parallel mono mode. Strapping the outputs in this manner does make the amp slightly more flexible, but agreed most people would have no use for this feature. Several years back I was consulting with a friend who had taken over running a large processor based EAW system that was grossly underpowered. His predecessor, who had spec'd the system, bought plenty of power amps but had assumed many would be used in bridge mode to get the required power. Unfortunately the amps weren't rated to bridge into the impedance of the speakers. Having the ability to run the amps in parallel mono would have greatly improved this system...unfortunately the amps were not Crown so it was not an you probalby know, most amp companies "parallel mono" mode only ties the inputs together. As the outputs are not strapped you don't get the benefit of the doubling of current into a given load.

    I imagine Crown will not repair a PowerBase amp because it is not economically practical. Have you priced new amps lately. Amazing the amount of power you can get for $300. Sending a PB3 to Crown for repair would probably cost over $200 round trip just for shipping.
  13. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    I'm not familiar with the FET1000. I owned two FET400 models and a FET900. All three had the same design flaw in that when the amp went into protection, triacs would fire and blow the output fuse. Sadly, these were connected to the amp side of the fuse. On protection, the circuit would blow all the output transistors.
  14. B-string

    B-string Supporting Member

    Sounds more like self destruct than protection? :D