Measuring/Scoping the Output of a Class D Amp

[chienmort]

Most Class D amps use bridging of some sort to obtain higher power. This means that you cannot connect an oscilloscope directly to the output as this woulkd connect one side of the amp to earth. Now most amplifier swill happily drive a transformer to step up the voltage to 100V for PA aplications so can anyone see a problem in using the windings of a transformer between an amp and a scope?

 

[Mello4]

Most Class D amps use bridging of some sort to obtain higher power. This means that you cannot connect an oscilloscope directly to the output as this woulkd connect one side of the amp to earth. Now most amplifier swill happily drive a transformer to step up the voltage to 100V for PA aplications so can anyone see a problem in using the windings of a transformer between an amp and a scope?

Consider using a differential measurement (two probes, two channels on the scope).

 

[rayma]

Some amplifiers cannot drive a load with a low DC resistance, like a transformer.
Regardless, the best way is with an isolated differential voltage probe such as this.
Blocked

 

[DUG]

Most Class D amps use bridging of some sort to obtain higher power. This means that you cannot connect an oscilloscope directly to the output as this woulkd connect one side of the amp to earth. Now most amplifier swill happily drive a transformer to step up the voltage to 100V for PA aplications so can anyone see a problem in using the windings of a transformer between an amp and a scope?

There should not be a problem but if you want to you could put an 8R resistor in series with each leg of the transformer and a 1R across the transformer....amp should drive that.

Just remember that some class D amps do not like open or light loads.