Can I use unregulated power for Op Amp?

[emretelci]

Hi there,

I am making an active crossover using op amps. My op amp requires +-15 volts. (It is TI OPA 1602 btw)

I am also using an Ice Power amplifier which already has "unregulated" AUX power output which is +-24volts.

So basically, can I use this unregulated voltage to power up my op amps? I also know I need to drop the 24V to 15V but I wanted to ask which is the best way to do this.

Thanks...

 

[MarcelvdG]

Either a pair of voltage regulators or a pair of resistors with Zeners, but in either case the voltage becomes regulated.

 

[abraxalito]

If the supplies are sourced from a switching converter and you care about sound quality I'd highly recommend some kind of discrete reg or cap multiplier or LC filter before any IC regulator. Reason being IC regs are poor at rejecting high frequencies such as come out of switchers.

 

[dannyjmf]

can ... but the signal to noise ratio will be compromised ... as long as you dont exceed the maximum power limits of the opamp

 

[hweb]

If you use the +/-24V directly from the IcePower amp you will likely destroy the op-amps. The best solution was mentioned before: Use a pair of voltage regulators (an LM317 for the + and an LM337 for the - supply are good choices, likewise a 7815 and 7915 all of which can be found at DigiKey).


Notwithstanding the previous comment, there is no need to filter the input to the regulators any more than the simple input capacitor shown in the typical application circuit (unless doing so helps you sleep better at night ;-). The op-amp itself will have reasonable PSRR which will fix any noise problems due to the minute amount of very high frequency noise than may be present at the op-amp supply.