What exactly is this preamp supposed to do? How much voltage gain and how little noise do you need? (I can tell you right away that feedback Rs in the hundreds of kOhms make a good noise and distortion generator. A 10k resistor has 12.6 nV/sqrt(Hz) of voltage noise, scaled to other values via sqrt(R/10k).) What kind of input signals and loads would it have to handle?
Jumping into building the thing is kinda pointless if you haven't thought of the specs first. I suggest you read this so you get an idea of how the pros do it.
I dunno what's supposed to be wrong with a LM317/337 setup. (The above example got away with bog standard 78xx/79xx jobs, albeit lower-noise ones, and still noise and power supply rejection performance of the finished unit is very good.) A "low-noise" config (electrolytic at the adjust pin and all) gives perfectly acceptable noise levels and regulation for anything that has ever heard of PSRR (and audio opamps tend to have at least 30 dB across the audio band at 20 dB gain, more at lower frequencies). Just make sure you use a good grounding layout, as not having one may reduce regulator performance to very modest levels.
Jumping into building the thing is kinda pointless if you haven't thought of the specs first. I suggest you read this so you get an idea of how the pros do it.
I dunno what's supposed to be wrong with a LM317/337 setup. (The above example got away with bog standard 78xx/79xx jobs, albeit lower-noise ones, and still noise and power supply rejection performance of the finished unit is very good.) A "low-noise" config (electrolytic at the adjust pin and all) gives perfectly acceptable noise levels and regulation for anything that has ever heard of PSRR (and audio opamps tend to have at least 30 dB across the audio band at 20 dB gain, more at lower frequencies). Just make sure you use a good grounding layout, as not having one may reduce regulator performance to very modest levels.
hi,
if I use LME49710HA for each channel, would it make any improvement building two +- shunt regs? or one for both opams would be enough?
if I use LME49710HA for each channel, would it make any improvement building two +- shunt regs? or one for both opams would be enough?
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