Watts vs Ohms round two!

Discussion in 'Amps and Cabs [BG]' started by sandman357, Mar 24, 2005.

  1. Hi,
    Thanks for the advice to my original post. I wanted to know the difference between a 300 W 4 ohm cab. and a 450W 8 ohm cab. (Sorry I started a tiff!)

    I took a look at my bass amp and it is a Carven PB200 Pro Bass that is rated at 200W rms and Min. Imp is 2 ohms.
    I am still thinking of the 450 watt 8 ohm 410 cab. I have a homemade cabinet with a 150 W 15 in. Crate replacement speaker in it. No clue about the ohms. Am I going to hurt anything if I hook all this together?

    As you can tell, I have no clue what the #!@$ I am doing. My ears will tell me if it sounds good, I just do not want my eyes to see smoke coming from anywhere!
  2. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY

    Before you connect all this together, you might want to be sure what the impedance of that 15 is. All references to the PB200 that I see are to the current run of PB200-15 combos, but assuming that you have a head those are based upon I'd be leery of going down to 2 ohms.

    From the Carvin site:

    • Power amp: 160 watts @ 8 ohms, 2 x 80 watts @ 4 ohms (two internal power amps bridged), typical THD less than .1%, Freq. Response: 20 to 20k Hz

    I believe if you combine a 4ohm and an 8ohm cab you'll end with an odd load...something like 2.6 which if your head can go down to 2 yer probably ok. I'd be careful of pushing those cabs too loud with that amp, since clipping (harmful distortion) could damage the speakers.

    Now, I'm sure others who know more than I will fill you in fer real.

    ****ah, I see the 'Carvin Museum' lists yer PB200 for 1988 and 1989:

    The PB200 was the smallest of the lot, at 200W. Also, the PB200 had only the parametric EQ, not a graphic EQ. The 400W PB400 had a 5 band graphic EQ, and produced 400W of power. The top of the line was the PB900, which produced the most power of any Carvin amp produced to date, at 900W. The PB200 sold for $369, the PB400 sold for $499, and the PB900 sold for $699. All three models were also available as rack-mountable units
  3. Just another note, if the speaker cabinets have a different ohm rating, then you will be pushing more through the one with the lower ohmage

    (i think)
  4. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    You can run the two cabs parallel with each other, even if the 15 is 4 ohm. But keep in mind that the wattage of a speaker only tells you how much power it will take before it melts down, and the impedance of the cab only tells you how many of them you can use before your amp melts down. That's it. Neither the quality not the quantity of the sound it will put out can be derived from knowing the wattage and impedance ratings.