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I need help with phase issues when running two amps together!
Old 16th August 2007
  #1
Gear Maniac
 

I need help with phase issues when running two amps together!

How can I get two amps to be in phase with each other. I am running two heads through one stereo cabinet so I know its not the cab. Do I change the phase inverter tube? Is it that simple?
Old 17th August 2007
  #2
Gear Maniac
 

Quote:
Originally Posted by Tone Monster View Post
How can I get two amps to be in phase with each other. I am running two heads through one stereo cabinet so I know its not the cab. Do I change the phase inverter tube? Is it that simple?

Get a Diamond ST-MIX pedal...
Old 17th August 2007
  #3
84K
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IBP
Old 24th August 2007
  #4
Lives for gear
make sure speaker cables are the same length, and all connection cables are as small as they can be.

No point in one side have 20f cable, and the other 5f.
either both 5 or 20
Old 26th August 2007
  #5
Gear Nut
 

One amp may have a different amount of preamp tubes. Easy fix would be to get an Axess BS2 and hit the phase switch on it. Axess Electronics Website
Old 26th August 2007
  #6
Gear Addict
 
carival's Avatar
reverse the polarity on one of your speaker cables. (resolder one end, switching the two wires. tip wire to sleeve, sleeve wire to tip). no cost, problem solved.
Old 27th August 2007
  #7
Gear Addict
 

Well,

It could be more that the 'phasing' is occurring because it's two different amps putting out two similar, but different signals. The reality could just be that sometimes the signals interact destructively and other times constructively.

If one set of speakers is making a positive excursion while the other is making a negative excursion (it won't be exact, but general movement of the speakers), than it's more likely a polarity situation.
Old 29th August 2007
  #8
Moderator
 
Blast9's Avatar
Are you running 1 dry and 1 through digital FX?

If so, the phasing is because of the latency of the AD/DA conversion in the digital FX unit.

Otherwise, check the cab's wiring as already suggested --- One speaker wired out of phase by mistake?

Last edited by Blast9; 30th August 2007 at 09:43 AM.. Reason: clarifying and spell-check
Old 30th August 2007
  #9
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Wes Kuhnley's Avatar
 

Quote:
Originally Posted by -Noodles- View Post
make sure speaker cables are the same length, and all connection cables are as small as they can be.

No point in one side have 20f cable, and the other 5f.
either both 5 or 20
What does cable length have to due with phase? Nothing my friend, nothing.

The answer is to make up a simple phase reverse speaker cable. Simply reverse the connections on ONE end of the cable and voila! you're back in phase! Be sure to mark the reversed cable well (spray painting the reversed end [be sure not to paint the actual connection] orange works well), or one day when you're trying to run two amps that have the same number of inversing gain stages (the source of your problem being that the amps you're trying to run now DON'T have the same number...), you'll end up with the same problem.
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