The CCS Denoisator with two BJTs in parallel (BC5x0) almost reaches the reference amplifier noise from this comparison: https://linearaudio.nl/sites/linearaudio.net/files/v4 jdw.pdf
I think with two ZTX in parallel it bests that as well. I think it's good enough as far as noise goes. And with a LM317-N it should have around 120dB of PSRR. Last measurements were done with a regular ST LM317.
Maybe for some particularly demanding circuits you could build a NoNoiser which is a different level of "low noise".
This circuit has already appeared earlier in the thread; it is based on the same principle as the x-noisers, except the active element is an opamp.
The advantages of opamps are the flexibility in the choice of auxiliary components, the fact that the output goes directly to R4/R5, meaning there is no need for large C16/C20 to avoid frequency peaking.
The cons are the higher cost, the necessity to make the supply bipolar, and most important, the performances: even with low R10/R11, it cannot come close to the noise of a BJT, even a humble BC338 or similar
The advantages of opamps are the flexibility in the choice of auxiliary components, the fact that the output goes directly to R4/R5, meaning there is no need for large C16/C20 to avoid frequency peaking.
The cons are the higher cost, the necessity to make the supply bipolar, and most important, the performances: even with low R10/R11, it cannot come close to the noise of a BJT, even a humble BC338 or similar
If you run a .tran sim without any options, you should get a more or less straight line, maybe with a stabilization period of a few seconds. The thread has many examples of transient simulations, often with different startup conditions to see what happens in a cold-start situation.
In doubt, post a screenshot of your result
In doubt, post a screenshot of your result
For PSRR, yes. However, the output noise and impedance benefit from the denoiser in all cases.
At high frequencies, a simple LC filter can be very effective and use moderate value components