DC+ and DC- needed

[jeffjmr]

I have one of those OPA541 signal generator amps. It works as advertised powering with my two channel Leader LPS-152. However this limits me to about 22v output with the Leader’s +/- 25v max supply and I need 30-40 output.

I also have a B&K 1743, a single channel 35v unit. I can get up to 50v by combining the Leader’s two channels, and with the B&K I could theoretically get + and - 35v which would get me my 30v output from the amp.

But the input to the amp has just three lines +, - and ground. I would have thought I could  connect one PS to the + and ground, and with reversed leads the other to - and ground but that does not work. Is there a way to accomplish this with effectively two single channel power supplies?

Thanks,
Jeff

[TimFox]

That connection should work:  what did not work right when you did it?  What voltages did you measure at "+" and "-" with respect to "ground"?

[jeffjmr]

I had 35 measured on the Leader and 35 on the B&K BEFORE connecting. I connected the Leader’s positive lead to the + and the Leader’s negative lead to ground. Still measured 35. Then connected the B&K positive lead to ground and negative lead to -.

At that point I got my expected 35- but only 17.5 positive on the device. I suspect a current limiting issue but that shouldn’t have been an issue because I had not yet introduced a signal so was not asking for any output.

Thanks.

[TimFox]

How much current was being drawn from the positive supply at that point?

[jeffjmr]

I hadn’t taken note the first time but I just tried again and indeed the Leader was current  limited. I missed the combined limitation of 1amp on the +/- 25v. I thought it could do 1amp each side.

Thanks for your help. I am now confident that another B&K which can do 6 amps will get me where I need to be.

Jeff