Testing amp fit dc

[dantheman91]

What you wanting to check for Dan?

Hi Grant

A friend of mine has a P40 but he says its got DC on one channel just wanted to check mine - but its working fine....

Bit stupid really...

[struth]

Well you want to test for dc volts, not current. Just put amp on and wait a bit for it to warm up. Speakers connected preferably in my opinion. No input and vol down. Put meter across speaker terminals colour coded. Initially use in this case use a bigger dc range than expected. You can always drop it to lower range if it doesnt register much. I wouldnt expect much, say 100mv tops . Check each channel. That will tell you what dc offset youve got approximately. If it were much more than 100mv you would start to hear it. A lot more and your speakers will fry. SS amps generally dont need speakers connected. Valve amps do need a load of some sort. Whether it be speakers or a big wirewound resister

[dantheman91]

Well you want to test for dc volts, not current. Just put amp on and wait a bit for it to warm up. Speakers connected preferably in my opinion. No input and vol down. Put meter across speaker terminals colour coded. Initially use in this case use a bigger dc range than expected. You can always drop it to lower range if it doesnt register much. I wouldnt expect much, say 100mv tops . Check each channel. That will tell you what dc offset youve got approximately. If it were much more than 100mv you would start to hear it. A lot more and your speakers will fry. SS amps generally dont need speakers connected. Valve amps do need a load of some sort. Whether it be speakers or a big wirewound resister

Thanks Grant - I'm still learning i find this quite interesting subject....

[struth]

Plenty info on youtube too Dan. Current testing is a bit different to volts and ohms, and meter has to be in the circuit as opposed to over it. But using ohms law you can tell lots by using these three tests in conjunction. Just be careful if near anything that is using higher volts or drawing a lot of current. Even speakers can draw a fair bit of current so don'tshort anything out