U1 voltages - why not higher?

[Jezza]

Are there any potential drawbacks to setting the voltages on U1 to values greater than +/- 18V? If I can adjust them for greater headroom now, why wouldn't I? Does the noise floor increase if the opamps run a little hotter? I can't imagine any other drawbacks.

Mine are at 20V right now and too warm to touch for long.

[tpryan]

If you really want full +32dBu headroom, set the voltage to +/-24v. The op-amps will get hot, but as long as you keep the chassis ventilated you should have no problems. Noise is not a function of power supply voltage.