Help with Op Amp outamp

ehous · 19th April 2011, 07:05 PM

I am experimenting with a op amp in a existing pre amp circuit. The wave is pointed at the bottom and flat on top. I have a working circuit and tested it, it works fine. I also tested an op amp out of the circuit and it was the same pointed an flat. I have a 2 channel scope and the the input circuit is good. All of this leads me to believe my test power supply is the problem. Obviously, I am not experienced and any help will be appreciated.

nightanole · 19th April 2011, 08:07 PM

Working with Cranky Op-Amps

janneman · 19th April 2011, 08:13 PM

Quote:

Originally Posted by ehous

I am experimenting with a op amp in a existing pre amp circuit. The wave is pointed at the bottom and flat on top. I have a working circuit and tested it, it works fine. I also tested an op amp out of the circuit and it was the same pointed an flat. I have a 2 channel scope and the the input circuit is good. All of this leads me to believe my test power supply is the problem. Obviously, I am not experienced and any help will be appreciated.

Are you using a dual supply, like + and - voltage? Is the input signal coupled to the opamp through a capacitor or directly?
Can you scribble a circuit diagram of your amp?

jan didden

ehous · 19th April 2011, 08:19 PM

+15vdc / -15vdc, 470uf caps on the input legs of the op amp. Note: very confusing circuit for servo amp input. thanks again.

ehous · 19th April 2011, 08:34 PM

Ignor previous circuit, the attached is the one actually in use.

ehous · 24th April 2011, 03:07 PM

I was informed that by finding dc in the output meant there was a break in the feed back circuit. after tracing it back, a missing jumper was noted. With jumper installed, dc is at zero & the wave was smooth.

19th April 2011, 07:05 PM	#1
ehous diyAudio Member Join Date: Jul 2006	Help with Op Amp outamp I am experimenting with a op amp in a existing pre amp circuit. The wave is pointed at the bottom and flat on top. I have a working circuit and tested it, it works fine. I also tested an op amp out of the circuit and it was the same pointed an flat. I have a 2 channel scope and the the input circuit is good. All of this leads me to believe my test power supply is the problem. Obviously, I am not experienced and any help will be appreciated.

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19th April 2011, 08:07 PM	#2
nightanole diyAudio Member Join Date: Feb 2009	Working with Cranky Op-Amps

24th April 2011, 03:07 PM	#6
ehous diyAudio Member Join Date: Jul 2006	I was informed that by finding dc in the output meant there was a break in the feed back circuit. after tracing it back, a missing jumper was noted. With jumper installed, dc is at zero & the wave was smooth.

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