mismatch in bridging 2 channels

[clovi_kate]

hi everyone.

why does my amplifier got problem when bridging 2 channels..
it creates a huge hum when i put loads to the two(positive) terminals.
is there anything wrong with the preamp or in the main amp..i found out that the bigger the load,also the hum..

But 2 channels operates well in normal mode(not bridge),the only thing is it has problem in bridging..

 

[AndrewT]

Hi,
is the amplifier designed to allow bridging?

Is the inverting switch/circuit working when you convert to bridged operation?

Is the load you are applying suitable for bridged operation?

 

[clovi_kate]

yes this amplifier is designed for bridging..and also the switch is absolutely working..

when loading around 16ohms,little hum can be heard..but at around 8ohms,huge hum occured..could this be at main amp or preamp..

regards,
Reign..

 

[Burnedfingers]

Are you supplying the input signal to the correct channel? Don't take offense here. Some amplifiers need the signal to be supplied to CH1 only with the input control if it has one set at zero for channel 2. Some amplifiers ask that the input be sent to channel 2 only and ch2's input be used to set the level and CH1 is set to zero. There are some amplifiers that you match both input level controls.

Are you suppling the signal to the amplifier as a unbalanced signal or balanced? If the amplifier has balanced capabilities and you are suppling an unbalanced signal you will need to put a jumper between the neg input and ground.

 

[Burnedfingers]

Sometimes there will be ground problems between different types of equipment. Is anything else grounded besides the power amplifier? As an experiment you might try using an adapter on your other equipment and see if the hum goes away.