Noise reduction -why the rage now ?

You were hearing something else. The science says we cannot hear RF directly. But as I described above, it could be getting into the circuits and getting amplified.

Um, yeah, no, that's exactly what I was hearing. Its called AM radio. Amplitude Modulation. The Radio Frequency is beyond the range of hearing. But it is modulated. Do you know what that means? It means its not all the same amplitude. Volume. The frequency stays the same but the amplitude of the frequency changes.

The rheostat coil and the crystal tune the RF signal in the wire to some specific radio frequency. When this happens you do not hear the RF itself. What you hear is the modulation in the amplitude of the RF signal. That's how radio works. Its a fact. You could look it up.

Sorry OP but I only have so much patience. You need to try. At least a little. Go back and read it again. Thanks!

No wait, seriously, I have to ask. How in the world can you be so arrogant as to tell me, especially after that explanation, that I did not hear what I in fact heard? From a science project designed and intended to accomplish that exact task? Without so much as a question or doubt? That is arrogance, right? Want to be sure and use the right word. Arrogant. Is there a better more apt term for it?

Well, your 10 paragraph response probably threw me off. All I’m saying is we cannot hear RF (directly), as it shoots through the air, in audio circuits.

BUT I admit, it’s still a problem as it gets conducted by all that metal (in a component). Hence my call for proper shielding of parts. Most high-end brands simply weren’t doing that...

As I said, the signal in electronics and wire is not the audio waveform, it’s an electromagnetic wave. Let’s call it theoretically a PURE electromagnetic wave. Unfortunately that PURE EM wave is subject to INTERNAL and EXTERNAL interference from RF and vibration, which produce NOISE or DISTORTION in the audio signal. This is why it’s necessary to reduce as much as possible ALL SOURCES of RFI and vibration. There is no substitute for Signal to Noise + Distortion Ratio. 🤗

Noise Reduction - Why the Rage?

I suspect that an an additional factor about the more recent 'buzz' (pun intended) around noise reduction is that ASR is shining a light on noise with their SINAID analysis (signal relative to noise+distortion) and then publishing a ranking of products with an occasional  reference to the actual sound quality.

This analysis may be getting a few things right and a few things wrong...but putting it all out there in this manner has to be getting the attention of a lot of companies and causing them to think about how to respond.

Take a look at post #97...and imagine that you are Border Patrol...on one hand getting a lot of accolades from many reviewers and many customers...and on the other hand getting blasted by inference that the review is not based on measurement and so how good can the product really be.

And, imagine that you are a company that has driven your SINAID numbers to vanishing low levels and you didn't think the sound was quite right...so you tweaked to get the sound where you wanted it, your SINAID numbers dropped slightly and now all of a sudden you are no longer recommended...fortunately though, your customers still love your product.

Geoff -I thought the wave carried the signal. Then, as far as RF damage -does it delay or ’erase’ the wave (or signal) ? Some links/studies would help.

And thanks snapsc, love those measurements. Esp how modern SS amps still heat up !!