Outta phase amps

[willjrockstar]

Today i set up my amps a bit different than normal, i came out of my triaxis (preamp)channel A into channel A of my simul class 2/90(amp). Then i came out of channel B of my preamp into another amp (roctron velocity).

So, one preamp feeding two amps. I turn up the volume for one amp and everything sounds fine, i turn up the volume for the other amp and it cancels out the signal.

Any guess why. Does this seem normal. I thought i had it hooked up this way last year and it worked out ok.

Thanks in advance for any ideas.

[garageband]

Seems like you could have one of the speakers of one of the amps (or the connecting cable) wired backwards - pos. to neg. terminals. Flip them on one of your amps and see what happens.

[willjrockstar]

Thanks Garageband, but I Didnt touch nothin. Usin factory made speaker cables,factory made cabs. Just got back my 2/90 (amp)yesterday though. Replaced all the tubes except for the preamp tubes. I,ll be testing your theroy very shortly.

Also failed to mention that 2/90 is fine in stereo operation as is the roctron.

[garageband]

The only other weird possibility is that one of the cables from the preamp is wired backwards at one end. Unlikely, but would take seconds to check with a multimeter.

[willjrockstar]

I checked it out and double checked, with one preamp feeding one amp,everything is normal. Using all the same brand newish and working cables, i connected the b channel of the preamp to the other amp and sure enough, same volume on both amps cancels each other out.

[Freddy G]

Are you saying that the amps totally cancel each other out? The two amps are outputting to 2 separate speaker cabs right?
If it were just speaker polarity that was out of phase, you'd still hear sound, but it would be "weird" if your head was just in the right spot.
Try GB's suggestions.

Usin factory made speaker cables,factory made cabs

Sometimes that doesn't mean shit
I've got a factory made cadillac that is full of mistakes and problems.
Never take anything for granted.

[willjrockstar]

Originally Posted by Freddy G

Are you saying that the amps totally cancel each other out? The two amps are outputting to 2 separate speaker cabs right?
If it were just speaker polarity that was out of phase, you'd still hear sound, but it would be "weird" if your head was just in the right spot.
Try GB's suggestions.


Thanks Freddy G for havin a look see. Two amps one stereo cab actually. Now that you say that i think when it was workin for me i was using two cabs. Ill give that a try.


Sometimes that doesn't mean shit
I've got a factory made cadillac that is full of mistakes and problems.
Never take anything for granted.

The cables have always worked in every other instance.

The symptoms: Two amps at equal volume tends to sound very centered (meaning not very left/right if that helps)and all of the bass dissappears when the two volumes are matched.

[willjrockstar]

Somehow i got this post all scewed up take a look please.

[willjrockstar]

Definately think yr right on with the polarity thoughts.