I am having some issues designing a simple amplifier circuit and was wondering if anyone could help me. I feel like I am missing something fundamental, but can't seem to grasp it. I'm using an AD826 dual operational amplifier using ±15 V supplies. I've breadboarded some very simple noninverting amplifiers with gain. Analog Devices recommends not using feedback resistors > 1 kΩ, so all of my feedback resistors are at that value. Lowering the value to 860 Ω allows me to add one stage before my problem occurs again but otherwise has little effect. Individually each stage yields a clean output. The feedback resistance is 1 kΩ and the sense resistor is 330 Ω. I also have a 220 Ω input resistor. I'm using a 1 μF cap and a 0.01 μF cap for decoupling at each power supply rail of each op amp. There is no non-inverting amplifier (with gain) configuration shown in the datasheet: http://www.digikey.com/product-detail/en/AD826AR/AD826AR-ND/611660 however, the inverting amplifier configuration shown does the same thing (I am assuming the 50 Ω resistor to ground at the input is the equivalent circuit of the function generator and not a component of the circuit). The problem is that once I connect enough stages in series, I see distortion in the output waveform (voltage output was less than half rail voltage) with a 150 kHz input sine wave (50 Ω generator output). A similar effect happens if I load down the output of a single stage - but I'm not sure how my chained circuits are loading each other down and how to remedy this problem. Any advice would be much appreciated.