Synergestic Black Fuse vs Audio Magic BeesWax

Who or what is the false authority being appealed to? The person making the claim is automatically the authority of the claim. Being unconvinced by a claim lacking a legitimate theory, supported by dubious evidence, and built on broken logic doesn't make somebody an authority or "false authority" because it takes no authority to observe the obvious. It makes the unconvinced party not a gullible fool.

I'm pretty sure your base rate fallacy claim isn't right either. That has to do with statistics and probabilities, and there aren't any statistics or probabilities in question it would apply to. Maybe it's not a Texas sharp shooters fallacy, but Geoff is certainly appealing to the authority a sales number represents, which is an insignificant number that doesn't prove anything.

The base rate fallacy, also called base rate neglect or base rate bias, is a formal fallacy. If presented with related base rate information (some fuses sold) and specific information (all fuses sold), the mind tends to ignore the former and focus on the latter. 

An argument from authority (argumentum ab auctoritate), also called an appeal to authority, or argumentum ad verecundiam, is a form of defeasible[1] argument in which a claimed authority’s support is used as evidence for an argument’s conclusion. It is well known as a fallacy, though some consider that it is used in a cogent form when all sides of a discussion agree on the reliability of the authority in the given context.[2][3] Other authors consider it a fallacy to cite an authority on the discussed topic as the primary means of supporting an argument.[4]

The claim 90,000 aftermarket fuses have been sold is not an Appeal to Authority. It’s actually evidence of the great success of the fuses, which lends credence to the idea that they probably work as advertised. Most likely audiophile fuse companies would have been run out of town on a rail a long time ago had their products failed to deliver. On the other hand, we’ve heard from some people who claim they didn’t get the results everybody else did. However, since there are only a few of them, it’s probably best to throw them out like any other outliers. We already know for any audiophile thingamabob there will always be a few who don’t get good results. That’s kind of how the cookie 🍪 crumbles.