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Paralell or Series?

Discussion in 'Amps and Cabs [BG]' started by HolbieBaker, Feb 21, 2002.


  1. HolbieBaker

    HolbieBaker

    Feb 21, 2002
    Dickinson, ND
    I have a 4 ohm Marshall bass head, 200 watts. I wanted to get an Ampeg 2x10 and an Ampeg 1x15 but don't have very much $. I want to get a Carvin 2L210 and a RL115 to stack, a cheaper route. The website says that the 15 is 8 ohms and the 2x10 is 4 ohms. Is there any way I can use both of these with my head and not damage it?

    p.s. It seemed kind of wierd to me to see a 2x10 that is not 8 ohms. Did I read the specs wrong. Any help would be greatly appreciated.
     
  2. mgood

    mgood

    Sep 29, 2001
    Levelland, Texas
    You read the specs right on the RL20T. The only 8-ohm bass cab they offer is the RL410T. All the others are 4 ohms, including the RL115.

    Running the RL210T and the RL115 on the same amp channel would produce a 2-ohm load.

    You could run the two cabs in series, which would make an 8-ohm load, but it would require you to build a rather funky speaker cable to make that happen.
     
  3. HolbieBaker

    HolbieBaker

    Feb 21, 2002
    Dickinson, ND
    If I am able to Bi-Amp the two cabinets is that the same as series? Pardon my ignorance on the subject but this is fairly new to me.
     
  4. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Nothing to pardon--nobody's born knowing this stuff, and most of us (certainly including me) still have plenty to learn.

    No, biamping is completely different from series. With biamping, you have two separate amps--either within a single unit, like the left and right outputs of a stereo receiver, or in two separate units, like, say, two different SVT power sections. You then divide up your bass signal at the preamp stage into two parts, a high part and low part. You do this with a crossover, which is either built into your preamp/head or a separate piece of gear. One part of your signal goes to one amp, the other part to the other amp. You can't biamp if you don't have two amps. As an example, you can biamp with a Carvin R600, which has two amps built in, but not with an SVT, which doesn't (unless you add a 2nd external amp).

    Series basically means you're running your power output through one driver before it gets to the next one. Thus, their resistances add up. Parallel means the power is effectively sorta split so that it goes to all drivers at the same time. That's crude, but I hope it gives the idea.
     
  5. HolbieBaker

    HolbieBaker

    Feb 21, 2002
    Dickinson, ND
    That helps alot. Thanks
     
  6. HolbieBaker

    HolbieBaker

    Feb 21, 2002
    Dickinson, ND
    One more question. If I run my trebble channel to the 4 ohm 2x10, and run the bass channel to the 1x15, also 4 ohms, what is the overall impedence? Will it damage my 4 ohm amp?
     
  7. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    AFAIK you can't do this, because you don't have two amps. If I'm understanding you correctly, you have a Marshall bass amp with a single output [that is, a single AMPLIFIER output, which may have more than one 1/4" jack hooked up to it], and this single amp puts out 200 W at 4 ohms. Because you only have one power amp, you can't split the signal into treble and bass regions and thus can't send each one to a different cab.

    Now, if you daisychain the two cabs off the single output, you will be hooking them up in parallel, which means that the total impedance will be 2 ohms. Not good if your amp is only rated down to 4. You might well damage it this way. I wouldn't recommend it.

    Even if there are two speaker output jacks and you connect one to each cab, most such outputs are connected in parallel, which means that you will still have a 2 ohm load and thus a likely problem.

    If I were you, I would at least consider forgetting about getting the two cabs you mention and instead look for a good deal on one good 4 ohm 410 (maybe a used Eden or Genz Benz or SWR or whatever--dunno who all makes 4 ohm 410s, though I know at least Eden does).
     
  8. HolbieBaker

    HolbieBaker

    Feb 21, 2002
    Dickinson, ND
    Actually my amp has two speaker outputs, plus a bi-amp feature with a trebble output and a bass output, with a trebble volume and bass volume knob on the front.
     
  9. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Well, why didn't you say so up front, old son? ;)

    No harm done. But in the future, when you ask technical questions about a setup, remember that it's better to give too much info than not enough. You'll find some very helpful people here, but the more info we have, the better we can help.

    To the point: are you sure you have two amps, or do you just have a built-in crossover that facilitates biamping, without the second amp that makes this actually possible? This happens sometimes. I used to have a Peavey that had a built-in crossover and various biamp-related controls--but it only had one amp, so biamping was impossible unless I bought a 2nd amp to hook up to it. I've never heard of a bass amp that could biamp and yet would be spec'd simply as 200 W @ 4 ohms. Usually, it would say something more like 200 W *per side* @ 4 ohms, or else (as some G-Ks do) something like 100 W (high) and 300 W (low).

    You might want to post some more info about the amp to get a better answer, or post the model number of the amp so we can look it up on the Marshall website.

    Not trying to bust your chops, just trying to help.
     
  10. HolbieBaker

    HolbieBaker

    Feb 21, 2002
    Dickinson, ND
    I will study the amp more closely and post again. Thanks for all the posts, it is helping me greatly.