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Connecting 2ch poweramp and two speakers

Discussion in 'Amps and Cabs [BG]' started by VoodooChild, Jan 10, 2016.


  1. VoodooChild

    VoodooChild

    Nov 9, 2008
    Hi,

    i have a Aguilar DB659, a DBX 160A and a Australian Monotor K7 in my rack and wonder how to connect all these to my two 8 Ohm cabinets. The cabs only got one 1/4" input each (i already got 2 speakon to 1/4" cables)

    I believe when i switch the poweramp to bridged mode only one output works, so i would need a Y speakon cable to connect my speakers as a 4 Ohm parallel load.

    Or i could use a Y XLR cable from the 160A to the poweramp inputs and use each channel separately but that would mean i have to use the DI out from the DB659 because i cant use the XLR out of the 160A when using the 1/4" as input.

    I could also exchange the 160A for a 2ch comp like the 166A but i don't really want to tweak each channel separately, I also don't use the comp too often. The DB659 has two 1/4" outputs, that would make it easy to connect the 2ch comp tho.

    So what would be the usual or best solution to this problem?
     
  2. Can the amp bridge into 4ohms? Lots of old amps don't.

    You may have channel linking on board the amp.
     
  3. VoodooChild

    VoodooChild

    Nov 9, 2008

    Yes the amp can do 4 Ohms in bridge mode but there is only one output active.
     
  4. B-string

    B-string Supporting Member

    Either add a second parallel jack on one of your cabs or build a simple cable box. One 1/4" jack for input from the amp to two 1/4" output jacks for speakers, the box can be plastic or metal.
     
    Downunderwonder likes this.
  5. VoodooChild

    VoodooChild

    Nov 9, 2008
  6. B-string

    B-string Supporting Member

    Because that is not what I was talking about, that is for instrument level not speaker (high power). I don't think anyone makes a commercial box for speaker level. It would be about $30 retail for the parts at the most. Drill some holes in a project box and wire all the tips together and all the sleeves together inside the box.

    That box would split your bass to two different amps, a stereo preamp or two mono preamps.
     
  7. VoodooChild

    VoodooChild

    Nov 9, 2008
  8. B-string

    B-string Supporting Member

    Functionally yes, the box just being a bit more reliable than a "Y" cable.
     
  9. mbelue

    mbelue

    Dec 11, 2010
    Are you sure you NEED to bridge your amplifier?
    If your cabinets only have 1/4" jacks I suspect they may have lower power handling.

    Can you give more detail on your cabinets?
     
  10. VoodooChild

    VoodooChild

    Nov 9, 2008
  11. BassmanPaul

    BassmanPaul Inactive

    Never ever bridge an amp using 1/4” Phone plugs! They simply cannot take the voltage and current put out by an amp in bridge. People do it but it is simply not advisable for your personal safety and the safety of your equipment. If your cabinets only have phone sockets replace them or have them replaced with NL4 type Speakon connectors. it’s a simple job and cheap to do even if you have to pay to have them changed. In bridge both the tip and the sleeve of the plug are live with respect to ground. If the plug pulls out of the socket and shorts, as they do, you short the outputs of the amps to each other. that’s not very good for the continuing operation of your amplifier.
     
  12. VoodooChild

    VoodooChild

    Nov 9, 2008
    Maybe you misunderstood, i bridge the amp by pressing the bridge button on the back, not via cables.
    I connect the poweramp to the speakers via a speakon to 1/4" cable.
     
  13. BassmanPaul

    BassmanPaul Inactive

    I understand perfectly and my comments still stand. Once you get past a couple of hundred watts phone connectors are completely inadequate for the duty. Have them changed out for Speakons.

    In case you don’t understand how bridge works, one channel is fed your signal. The other is fed an identical one but 180 degrees apart. Thus as one output goes positive the other goes negative by the same amount. Accidentally shorting these together will cause damage to your power amp.

    Speakons can’t short during connect and disconnect. Phone plugs do - every time.
     
    Last edited: Jan 10, 2016
  14. BassmanPaul

    BassmanPaul Inactive

    Additionally, I have used stereo power amps since the early Eighties, the first of which I designed and built.. I’ve yet to feel the need to bridge any of them. I run mine parallel moro so each output carries an identical signal. I hang a 4Ω cabinet from each one. This is the same as I have done from day one. :)
     
    Radio likes this.
  15. VoodooChild

    VoodooChild

    Nov 9, 2008
    OK, thank you for the explanation but i love these speakers and i can not get them as 4 Ohm, so that is not an option. The best thing to do is changing the connectors to speakon but i would still run the amp in bridge mode cause i get full power on 2*8 Ohm cabs (=4 Ohm in parallel).
     
  16. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    What you need is a signal level splitter Y cable to split the output of the comp into 2 outputs to drive the stereo inputs if the amp. Presumably you are using the XLR output from the 160, and your amp has XLR inputs so all you need is an XLR female to 2 XLR make splitter Y cable. Standard stuff for pro audio shops.

    I recommend against bridging for this application. The amp's ratings skirt around 3 ohm stereo and 4 ohms bridged operation which may be that under hard drive conditions the amp may not perform as intended. Operating at stereo 8 ohms is only a dB or so lower maximum SPL anyway.
     
    Last edited: Jan 10, 2016
  17. VoodooChild

    VoodooChild

    Nov 9, 2008
    So far i like this solution the best. Thank you.
     
  18. BassmanPaul

    BassmanPaul Inactive

    I was not suggesting that you change anything per se. The difference in volume between an 8Ω cabinet and a 4Ω version is not all that much. If you switch both cabinets to speakon you will be safe from an accidental shock. Our friend @agedhorse can attest to how bad a shock you can get from an amp in bridge.
     
  19. VoodooChild

    VoodooChild

    Nov 9, 2008
    I would like to thank everybody for their input. Think i will wait couple of days for some more suggestions but for now i am almost certain to get me a XLR Y cable wit female/male/male config.
     
  20. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    With big amps, bridged voltages can be high enough that you may wet your pants if not seasoned to shocks. There are amps now that swing >250V peak.
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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