Almost all tube manufacturers....they pick caps, etc. by ear....and they don't measure any different.This statement is false- they do indeed measure differently (whether some companies bother to measure the differences is a different matter). We use custom made resistors as well (made by Caddock); they sound better but they also measure better.
Most equipment stand manufacturers......I mean, can you measure a better stand?Certainly! Sound Anchors was measuring the differences in performance of their stands 30 years ago. Its not hard.
More like calling you out, on your snake oil mods, that you don’t backup with any measurements, just a fusers "trust me it works"
Its easy enough to measure the effects of a fuse, and the different fuses. Its not rocket science either. All you need is a DVM. Having said that I'm personally not a fan of boutique fuses. At least one of them uses a Teflon tube to 'damp' the fuse element. The problem is the fuse actually has to blow in order to protect; this type of fuse can have the metal of the fuse element go liquid and finally to a plasma state simply because of that Teflon tubing in which its held. Such a fuse will not reliably fail at its rating, and thus we don't recommend them.