Direction of aftermarket fuses (only for believers!)

" If a component has more than one fuse use a DVM (Digital Volt Meter) to determine direction of current in the circuit. "

The problem with this of course as many have pointed out repeatedly in various threads is with alternating current direction switches many times per minute.

As I understand it it is possible to determine power flow direction in an AC line, for example with an overhead transmission line which way is the source (the power plant). With a circuit schematic perhaps it is possible to determine which way to the components power supply from any particular fuse location? That would be a question for Almarg or other EEs perhaps to answer.

The thing is assuming fuses are directional and that orientation is a significant factor for best sound, you would look for devices that have the directions clearly indicated somehow plus a fuse with the same so things can be done easily without an electronics background. If all that is true but no indicators, someone in design was asleep at the wheel and the customers are paying the price to have to figure it all out.

Could you imagine buying an expensive portable device using 19 batteries in 19 different locations and no indicators which way to place each? That is essentially the worst case scenario for teh NAD assuming fuse direction always matters.

Mapman, you probably didn’t get the memo. Fuses are not only directional in DC circuits, they’re directional in AC circuits, too. You know, when the alternating current is moving in the correct direction the voltage drop is measured as lower across the fuse than when the current is moving in the other direction. Capish? Yes, I know you wish only to learn, Grasshopper.  But first you have to put on your thinking cap.

IMHO Ted at SR puts out a disclaimer and I think it is more likely that a manufacturer keeps the same process (why change?). AMR produced fuses en masse as did Isoclean and for the aforementioned brand, they are, so far, consistent IME (same as HiFi). Another indicator is that HiFiTuning users have consistently reported the direction in the same way as some SR users. Thanks Charles1dad and others for sharing this. It is people like you that has made this hobby more fun and trustworthy for me as I have made most of my purchases based on comments on the Gon. People like GK, though a bit overzealous in postings for my liking, seems to be genuinely interested to find out/help out. He may know that nerdy people can at times put off people (polarizing is only good for electric components) and sympathy counts when buying gear, hel-loo :-). May I also suggest using PMs (e.g. to mapman) instead of a public shout out? Thank you!

As for the circuitry, I know what upstream is as I have the schematics of the amp. Before submitting this dreaded thread, I have the following strategy: try first the fuses on L+R channels with open cover, assuming the fuses are labeled in the same way and proceed from there. Now I will resort to making sure that the 3 main channels (L, R, C) sound coherent. I simply don’t have time for the other channels and will assume that the labeling process is less random that I hoped for. This should be a 1-month project, included bypassing some caps, not a lifetime trial and error. I dread of the amp surviving me.

Again I would like to stump on the example of coupling caps (in tube amps, etc) where most manufacturers don’t care to implement it the correct way (aka polarity/direction), leaving improvements to modding shops and aware DIYphiles (wait, do I smell a conspiracy?).

Lesson learned, early adopters (we should have been over that for fuses but obviously we’re not) pay the price/scrutiny.

I sensed that the fire on my stake seems to fizzle out, you all have my gratitude for that!

Jazz, sorry for intruding on your soapbox.   Good luck with your endeavors.

Geoff,
I didn't intend to imply that the SR fuse lettering suggested current flow,  rather that this is the orientation providing the best sound quality consistently in my components. 
Charles,