Need Advice: Vinyl Hum Issue

I have a Rega P3-24 which I think is a similar configuration.  It doesn't have a grounding cable - it grounds through the left RCA which I could not get to work on some phono preamps.  So I had a lot of hum issues until I found the right way to get that ground to actually be grounded.

This sounds like maybe two separate issues - either ground loop hum or acoustic hum bleeding back from sub to TT, and then separately possible ground hum from how problematic Rega's ground design is. 

First suggestion:  eliminate the sub from the equation and take it out.  Then work on absolute quiet grounding from the Rega.  Once you have totally quiet without the sub, then see if you can determine what is the issue once the sub is back in. 

@viridian 

richardbrand spelled my user name incorrectly above, so I simply pointed out that, in that one verifiable aspect, I found AI to be superior

I'd like to claim that I misspelt your name on purpose to prove my post was by a "human" - something Audiogon asks me to prove every few minutes!

But alas that claim would fall into the realm of alternate facts.

Usually, when I start to type @ to link to usernames, I get a drop-down list.  But often this facility does not trigger.  By refreshing the page, and proving I am still 'human', I can usually get the drop-down list.  Usually.

Sometimes, when in the body of a reply. the @ triggers the drop-down but I cannot select anyone ... frustrating.

By the way, I wish ChatGPT would learn the correct capitalisation for "Sonus faber" which is prominent in another active thread.  I guess the problem is that so many humans get this wrong, ChatGPT follows the herd.  Once it processes this thread, it might have second thoughts.

I asked him why he got it wrong:

• Token-Based Generation: Large Language Models (LLMs) like ChatGPT generate text one "token" (a word fragment or character sequence) at a time based on statistical probabilities. It is possible for the model to select a less probable or incorrect token, leading to a typo or misspelling, much like a human making a typo, but without a "backspace" button for immediate correction within the stream of thought.
• Training Data Nuances: The model's knowledge comes from a vast dataset of internet text. If a specific, less common proper noun like "Sonus Faber" (a high-end speaker brand) was frequently misspelled in the training data, or if mentions of it were rare, the model might replicate the common errors or struggle with consistency.

ChatGPT is far more than a Large Language Model, which we should assume is building a neural network of everything on the Internet.  It also incorporates the ability of Expert systems to make logical inferences and to explain how it uses those inferences to reach conclusions.

@lanx0003 

You quoted 

Yes — acoustic feedback is absolutely in play here, and in fact it ties perfectly into the woofer pumping, rattling, and the way the sub changes the behavior.

But my old eyes cannot find this in ChatGPT’s original response, or anywhere else in this thread!  I presume that this was the generated response to a new question like "why didn’t you use the phrase "acoustic feedback".  So thanks for asking this question, as requested, on my behalf.

@viridian noted that:

AI can’t even use the common term "acoustic feedback"?

By the time ChatGPT gave its (his?) second response, lo and behold it included the term "acoustic feedback".

By the way, a decade or so ago, I led a team of IT guys and lawyers to build an application using a legal Expert System.  The primary goal was to assess whether a financial adviser was lawfully able to provide financial advice to a client.

The Expert System (Softlaw) used backwards and forwards chaining inference engines operating on ’facts’.  Softlaw ’facts’ had three potential values - true, false and don’t know.  I introduced a fourth value - haven’t asked yet.  Up to 5000 facts could come into play.

The resulting application was phenomenal at explaining why it reached each assessment, including links to the legislation and regulations.

To all interested, Rega Planar 3 has its ground wire tagged to the signal ground shield of one channel, so it has no “ground wire”.  Like an AR XA/B in that regard.

One question I have…why is OP’s KC62 high level connection to only the L channel?  Does he not care for R channel bass?

A sophisticated sub like this KEF should have a very steep DSP filter to eliminate frequencies below its tuned cutoff, shouldn’t it?  Doesn’t it?

So far as I can tell from a quick scan of recent posts, we still do not know what cartridge was being used in the system as described, AND we do not know whether the symptom goes away when the OP reverts to a bare wire connection. It may make all the difference to do that, but there is also the possibility that the bare wire to spade connector thing is a red herring, that the hum arose coincidentally when the change was made but that the change in connector was not the cause. Also, Grado cartridges, for reasons that are known but which I cannot recall, are particularly prone to hum with the peculiar Rega ground system.