Amp to Cabinet Question:

Inspector #20

Inspector #20

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So, my Line 6 Spider II HD-75 Head says "Use only with 4 ohm cabinets."

However, the Jackson 4x12 cabinet is printed as 16 ohm.

I know I can wire it differently, parallel etc., but what's safe??? More than 4 ohms, but not less???
 
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Basically it's this, you can go up(cab impedance.) But going down (cab impedance.) puts a strain on the amp, especially with solid state amps and will eventually blow the amp. Here's more info:

 
Looked it up - you are safe. That amp is "4 Ohms Minimum" which is pretty standard. You can connect an 8 or 16 ohm cab without worry.
 
Gball is correct, you need a minimum 4 ohm speaker load connected to the amps output, 8 or 16 ohms will be fine, but to get the full 75 watts output you need a 4 ohm speaker load. From the Line 6 support archive (spider 2 HD-75 amp), 75 watts @ 4 ohms, 40 watts @ 8 ohms, 20 watts @ 16 ohms. Seeing as your 4x12 is 16 ohms, it's highly likely that each speaker is a 16 ohm job & the cab is wired either series/parallel or parallel/series to arrive back at 16 ohms total load. Supposing they ARE 16 ohm speakers you can "parallel" all four speakers to obtain a total load of 4 ohms & thus get your amps full rated output of 75 watts.
Conversely, though highly unlikely, the speakers could be rated at 4 ohms with them being all wired in series to give a total load of 16 ohms. I say "highly unlikely" because in this scenario, should one speaker blow the whole cab goes open circuit, presenting no load to the amp. For this reason you don't see cabs wired this way, but just supposing they are 4 ohm speakers all series wired, you could still make the cab a "4 ohm cab" by wiring the 4 ohm speakers either series/parallel or parallel/ series. Hope this helps. Cheers
 
ivan H said:
Gball is correct, you need a minimum 4 ohm speaker load connected to the amps output, 8 or 16 ohms will be fine, but to get the full 75 watts output you need a 4 ohm speaker load. From the Line 6 support archive (spider 2 HD-75 amp), 75 watts @ 4 ohms, 40 watts @ 8 ohms, 20 watts @ 16 ohms. Seeing as your 4x12 is 16 ohms, it's highly likely that each speaker is a 16 ohm job & the cab is wired either series/parallel or parallel/series to arrive back at 16 ohms total load. Supposing they ARE 16 ohm speakers you can "parallel" all four speakers to obtain a total load of 4 ohms & thus get your amps full rated output of 75 watts.
Conversely, though highly unlikely, the speakers could be rated at 4 ohms with them being all wired in series to give a total load of 16 ohms. I say "highly unlikely" because in this scenario, should one speaker blow the whole cab goes open circuit, presenting no load to the amp. For this reason you don't see cabs wired this way, but just supposing they are 4 ohm speakers all series wired, you could still make the cab a "4 ohm cab" by wiring the 4 ohm speakers either series/parallel or parallel/ series. Hope this helps. Cheers
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Awesome!!!! Thanks!!!!
 
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