amplifier anomaly

[nostinkingloops]

i have a pair of monoblock amps. measured gain from both amps is the same - absolutely identical. what i'm hearing is that the left side is louder than the right. i swap the amps (not the cables, not the speakers -- just the amps). the balance shifts so that now the right side is louder than the left. adjusting the balance control on the preamp fixes the problem: no matter which side dominates, i can "center" the sound.

can anyone suggest an explanation?

 

[Sokel]

i have a pair of monoblock amps. measured gain from both amps is the same - absolutely identical. what i'm hearing is that the left side is louder than the right. i swap the amps (not the cables, not the speakers -- just the amps). the balance shifts so that now the right side is louder than the left. adjusting the balance control on the preamp fixes the problem: no matter which side dominates, i can "center" the sound.

can anyone suggest an explanation?

Do you have a multimeter?Can you measure?

 

[pjug]

i have a pair of monoblock amps. measured gain from both amps is the same - absolutely identical.

You measured gain or output voltage?
Do you know that the input signal is not the problem?
Did you measure amp output 20Hz to 20KHz?
Did you confirm with a microphone that one channel is really louder? Edit: not necessary just measure the amp voltage with a multimeter.

 

[nostinkingloops]

Do you have a multimeter?Can you measure?

i didn't try. the amps are 15 years old, and i thought it was time to have them checked over for possible recapping. before making any changes the technician performed the measurements and determined that the amps measured identical output and gain. it's a mystery (for now).

 

[nostinkingloops]

You measured gain or output voltage?
Do you know that the input signal is not the problem?
Did you measure amp output 20Hz to 20KHz?
Did you confirm with a microphone that one channel is really louder?

i asked the tech to explore all possibilities. i'm assuming that he's savvy enough to have done everything you suggest. but i'll double check your list with him to be sure.

 

[Sokel]

i didn't try. the amps are 15 years old, and i thought it was time to have them checked over for possible recapping. before making any changes the technician performed the measurements and determined that the amps measured identical output and gain. it's a mystery (for now).

I would measure with various test tones (at low volume! ) if I were you.
Put it in AC scale and see if the readings are similar.

 

[pjug]

i asked the tech to explore all possibilities. i'm assuming that he's savvy enough to have done everything you suggest. but i'll double check your list with him to be sure.

Did you try a different source?

 

[pjug]

i didn't try. the amps are 15 years old, and i thought it was time to have them checked over for possible recapping. before making any changes the technician performed the measurements and determined that the amps measured identical output and gain. it's a mystery (for now).

So he didn't do any work on the amps? And you didn't notice the imbalance before you had them checked?