Some op amps are specifically made to work with a single-ended supply so their negative supply can connect to ground. Of course, that presupposes that you don’t need a negative voltage output.

The fastest non-decompensated op amp is the THS4304, which can work in any configuration all the way up to its unity-gain bandwidth of 3 GHz. But before you run off and buy this chip to build a ...

Part 5 provides spec summary of the GP/R K2-W vacuum-tube op amp and discusses measurement constraints/conditions and LTspice modeled output. The K2-W vacuum-tube op ...