Zener diodes are NOISY! I suspect that they are also much faster reacting than any op amp based regulator, so in that regard they may have some advantages.
Another approach is to use a zener diode as a reference for a series pass transistor. You filter the zener diode well so that it's noise is reduced, then the transistor handles most of the load. Select a fast transistor and you may well have a better sounding regulator than many, if not most op amp based designs.
But if you are using an op amp based design, keep in mind that at higher frequencies it's the decoupling capacitors on the output of the regulator that are going to be supplying the transient currents to the amplifiers, so pay special attention to power supply decoupling.
Don't forget that capacitors have series inductance and a natural resonance. You might use a 10µF electrolytic with a low ESR capacitor bypassed with a 1uF polypropylene film cap, bypassed with a 0.1µF polypropylene film cap. If your amp runs cool enough you may get by using polystyrene capacitors which are even better sounding, but more expensive and physically larger.
Also pay close attention to avoid ground loops within your layout. Pay attention to where the decoupling capacitors are grounded. You don't want the transient currents flowing through the capacitor ground connections to modulate another part of the circuit.
Scott Novak
Another approach is to use a zener diode as a reference for a series pass transistor. You filter the zener diode well so that it's noise is reduced, then the transistor handles most of the load. Select a fast transistor and you may well have a better sounding regulator than many, if not most op amp based designs.
But if you are using an op amp based design, keep in mind that at higher frequencies it's the decoupling capacitors on the output of the regulator that are going to be supplying the transient currents to the amplifiers, so pay special attention to power supply decoupling.
Don't forget that capacitors have series inductance and a natural resonance. You might use a 10µF electrolytic with a low ESR capacitor bypassed with a 1uF polypropylene film cap, bypassed with a 0.1µF polypropylene film cap. If your amp runs cool enough you may get by using polystyrene capacitors which are even better sounding, but more expensive and physically larger.
Also pay close attention to avoid ground loops within your layout. Pay attention to where the decoupling capacitors are grounded. You don't want the transient currents flowing through the capacitor ground connections to modulate another part of the circuit.
Scott Novak