Originally Posted by Nerdyrocker
Is there a way to test one of these to see if it is in good condition without putting it in the mic pre circuit?
I want to test it for my Seventh Circle Audio A12 pre.
You'll have to put it in some kind of circuit if you want to test it. Since you can't measure internal voltages in it, the only way you can test it is to power it up, apply a signal, and see what you get out the other end. If you don't want to use an existing circuit you've got on hand (presumably the circuit that will eventually be home to the amp) then you would have to build a new test circuit. That seems like a lot of work, basically building a new preamp just to test the amplifier. If you've got a known good preamp on hand, then slapping the 2520 in there will be the best way to test the amp.
What's your reasoning for wanting to test it without putting it in the preamp circuit? Are you having trouble with your preamp and trying to determine whether the circuit or the amplifier is to blame?