Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

daisy chain?

Discussion in 'Amps and Cabs [BG]' started by jonasp, Jul 19, 2003.


  1. What is daisy chaining? How do i do this? What is bridging in momo (bridged mono)? how do i do this?

    Im thinking about getting a QSC RMX 850. So, it gets 850w when bridged in mono.
    Also, im just wondering exactly what daisy cahining is and how to do it?

    Thanks, Pete
     
  2. BFunk

    BFunk Supporting Member

    daisy chaining is a way of connecting 2 cabs to one amp. The output of the amp is connnected to one cab. The second cab is connected to the first. It is a very common setup.

    Bridging is a way of getting a stereo amp to work like a larger mono amp. The QSC will come with instructions on how to set it up this way.
     
  3. Rather than lugging around a big ol 810, you can get 4 four ohm 210s. That way you can use 1, 2, 3, or all four safely. You would daisy chain them in pairs, creating two eight ohm loads which would make a ofur ohm load together
     
  4. ok..so then, when i daisy chain the cabs, to figure out the load going to the amp, i add the impedances of each speaker? right? so like 2-many said, i would have 8 ohms going to each channel, thus making the amp put out the 4 ohm wattage level? hope that made sense
     
  5. BFunk

    BFunk Supporting Member

    No. 2-mny-drummers would be right if the speakers were connected in series, but 99.99% of the time speakers are connected in parallel. (At least the external connectors are in parallel.) In this case two 4 Ohm speakers in parallel would have a total load of 2 Ohms. Two 8 Ohm speakers would have a total load of 4 Ohms.
    The formula is the total impedence of loads in parallel is the inverse of the sum of the inverses of the individual loads. 1/8+1/8=1/4=>1/1/4=4. If you don't get that, just remember it is about 1/2 of the original load.
     
    Thor likes this.
  6. ok, now i'm confused....if daisy chaining two 8 ohm cabs gets you a 4-ohm load....then why not just go stereo and plug each cab into an output?
     
  7. ok, so then what is hooking cabs up in parellel? in Series?
     
  8. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Series vs. Parallel...

    Most two jack cabinets (or amps) have the jacks connected in parallel. What this means is that either speaker will continue to function if the other one dies or is disconnected. A similar set up is a light fixture with more than one bulb. If one bulb burns out, the other one(s) stay on. The bulbs are in parallel. The total impedance that an amp sees when the speakers are in parallel is always less than one of the cabinets individually.

    If the speakers are in series, the total impedance goes up (it's the sum of the cabinet inpedances). If one speaker blows or is disconnected, they are all shut off. Think Christmas tree lights now, where if one bulb burns out, they all go out.

    Kennyhoe...an amp running in the bridged mode puts to paralleled cabinets puts out more power than it would if the cabinets were each connected to thier own power amp channel. It's an electronic way of tricking the amp into thinking that you're running at a lower impedance than you are. If you look at stereo amp specs, it's output briged into 4 ohms is usually the sum of its per channel rating at 2 ohms.

    If the power amp can't handle a 2 ohm load per channel, it will probably be limited to 8 ohms in the bridged mode (because each channel is "seeing" a 4 ohm load).

    Clear as mud?;)
     
  9. Good lord. I was right, don't go steering him wrong :spit:
     
  10. BFunk

    BFunk Supporting Member

    My point is pretty easy to verify. Just put an Ohm meter on the speaker cable that you would plug into the power amp. You will see that it is less than the individual cab ratings. (It will likely be much lower than expected because DC resistance is typically lower than nominal impedence.)
     
  11. 4 ohm 210 - 4 ohm 210
    /
    AMP = 4 OHM LOAD
    \
    4 ohm 210 - 4 ohm 210
     
  12. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    I'm not sure what you're showing us, but if I read your drawing correctly, two sets of 4 ohm cabinets are daisy chained together then connected to the amp.

    If this is correct, each pair of 4 ohm cabinets becomes a 2 ohm load and then the amp sees only 1 ohm. Unless its a MacIntosh MC2300, it isn't going to be very happy...
     
  13. BFunk

    BFunk Supporting Member

    This is entirely do-able if you are running a stereo amp in stereo or dual mono mode. Each side will see a two Ohm load. However, if this is like this:


    AMP
    |
    4 ohm 210 - 4 ohm 210 - 4 ohm 210 - 4 ohm 210


    You will blow up the amp.
     
  14. My diagram is dual mono
     
  15. so this is a possible way of running 4 cabs if your AMP only has 2 outputs for cabs??? Like, say your amp can take a two ohm load, you can daisy chain 2 8 ohm cabs from each output so you can have a total of 4 8 ohm cabs?
     
  16. That would give you an 8 ohm load all together.
     
  17. Wrong, that would end up being a 2 ohm load to the amp.
    2x8 ohms gives you 4 ohms per output on the amp.
    2x4 ohms is a 2 ohm load.

    Outputs on a mono amp are wired in parallel, as are the connectors on cabs.

    Now in theory it would be possible to wire two of the cabs in series with each other per side giving you 16 ohms per output on the amp. This would give you a total load of 8 ohms.
    You would need to create custom cables in order to do this though.
     
    tfer likes this.
  18. 2x8 ohm load daisy chained is 16 ohms, not 4. My cabs have an iin and an out for daisy chaining.
     
  19. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    What kind of cabinets do you have? All the cabs I've seen have the jacks in parallel. What you describe has the jacks in series.

    I just figured out a way to use two 1/4 in. jacks (one of them a switching jack) to connect the second cabinet in series with the first (and still have to original speaker function when the second one isn't plugged in), but I'd be surprised if any bass cab mfr. does that...I sure wouldn't want to for high power applications.
     
  20. BFunk

    BFunk Supporting Member

    I have used these special external connection boxes that turn the cabs into series connections. You connect the amp to one side and then the speakers into the other. (Sort of like a hub in computer network connection.) Otherwise, if you are connecting one speaker to the next using the standard input and output connection on the back of the cab, 99.9999% of the time you are creating a parallel connection.