Fuse Direction for Pass Labs Amp and Preamp

Would it be fair to say (or infer) that some of these boutique fuses are somewhere along the arc between a bog standard fuse and those FNM fuses? That they are definitely a step up but still nowhere near a FNM fuse? That could be why we hear a difference: they're simply a better made fuse, kinda like what you got with the FNMs. Just saying..

Some of the boutique fuses we've seen are inferior and some are OK so there's not a good answer to this question. We've seen some that employ a Teflon tube to damp the motion of the fast blow element; this type of fuse might not blow correctly since the metal can go to liquid and still be supported by the tubing- at that point would eventually become a plasma. I'd stay away from any fuses constructed in this manner. We've seen some that don't hold the current they are rated for and some that won't blow until you're a bit over spec! None of these are good situations. Having an equipment failure on this account wouldn't be a good thing so when people ask me about this on the phone I let them know what we've seen.

Cable is cable. Fuses are fuses. OAK is the only speaker finish. Class Ds suck. Why are you still using tubes? Concrete everything to the floor. Speaker spikes work. and the biggest of all, Come to AG and get a blast from the past.

@helmholtzsoul 

You might be interested to know that my LP mastering lathe, which was originally built about 1949, sat atop a custom table that featured adjustable points for feet. So the idea of the points that so many audiophiles use has been around a very long time.

You might also find this interesting: You can look at any amplifier as having a perfect amplifying element with a distortion element (nonlinearity) in series with the signal. Put another way the differences you hear in amplifiers is simply the distortion signature. Because of this, if you have the distortion signature of a tube amp and were somehow able to put it in a solid state amp, the solid state amp would sound like a tube amp. We discovered how true that really is when we were developing our class D amplifier, in which the non-linearities tend to generate lower ordered harmonics rather than higher orders, so it has the smoothness and lack of harshness you expect from a really good tube amplifier although a bit more transparent.

It is the distortion signature of tubes which has kept them in business so long after being declared ’obsolete’ in the early 1960s. But now you can get the same distortion signature in a solid state amp (although maybe 2 orders of magnitude lower, allowing for greater transparency) with the same liquid mids and highs.

We’ve encountered cheap fuses that are not worth using. A a good quality fuse like Bussman or Littlefuse is hard to beat: if you are trying to use a boutique fuse, the former brands should be your ’control group’. In 1990 when designing our MA-2 we recognized that fuses were a problem, so we use a different kind known as an FNM. https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/fuses/bussmann-series-supplemental-fuses/supplemental-fuses-midget/bus-ele-ds-2028-fnm.pdf This is a physically larger fuse employing dual elements and a larger fuse holder that exerts much more pressure on the fuse contacts, which are also much larger. They and their fuse holders easily outperform any boutique fuse made today. We did this and also used dual power cords on each chassis to minimize the internal and external effects of AC power wiring.

So please take it that when I say the direction of a fuse isn’t a thing, its with the awareness of fuse effects going back over 30 years, long before there were any boutique fuses.

Inescapable FACT: No one understands exactly how electricity works.   

      That’s why there’s so much Electrical THEORY.     

People risk their lives on electrical theory, just as they do the theory of flight. I suspect you might mean 'hypothesis' rather than theory.

OK you got me, you win, 10ga OFC spools cable is just as good as SRs speaker cabling. I suppose you hooked it all up and did a side by side on two identical systems too? GIVE ME A BREAK, you did NOT. Second if you can’t hear the difference in a UP-OCC/teflon weave from your 10ga OFC spool wire. QUIT trying your hearing is SHOT.

My hearing certainly isn't what it was, but I hear differences easily enough. However my employees' hearing is much better and they couldn't hear any significant difference either; neither could the guy that lent us the cables! That might be different if the speakers were 4 Ohms but they are 16. That makes a big difference.

None the less saying something is hogwash, is hogwash especially when it comes to cables and wire direction. It’s simple, cables sound and work differently in one direction than the other. The reason to condition cabling the direction it is pushed through the dies. It not only matters, it’s the difference weather I buy your STUFF or not.

Ted Denny hasn’t said a word, yet you bring up his products as if YOU tried them. I’d really doubt that one.. Great products at an astronomical price. Still great products with a FULL money back guarantee. There is NO reason for anyone to complain about that.. You don’t KNOW about a product so you get to slam it. No!

Quite the word salad! Complete with self contradiction. Apparently the comment about Ted isn't directed at me; I didn't bring him up. But coincidentally, we've been playing some Synergistic speaker cables in the shop for the last month. Our customer that brought them in exclaimed how they were so transformative. We ran a comparison, just for fun, between them and our shop cables, which we made up from 10ga oxygen free copper wire. Everyone in the shop was challenged to hear a difference. Our speakers though are 16 Ohms and speaker cables are far less critical when driving 16 Ohms as opposed to 8 or 4 Ohms.

It’s not a question of truth, it’s a question of weather you keep up with what the heck is really going on.

Priceless! 🤣

Spoiler alert: Truth is what is going on.

You never owned Bose 901s or have read why Amar Bose designed them that way, I'm guessing.

@russ69 This is such a great example of what I'm talking about (the myth bit)!

I'll put it to you this way: If someone comes up with a way to get home stereo electronics to favor a certain genre of music, they will be a millionaire overnight. There really isn't any way to do it (if you feel I'm incorrect about this, by all means, please get out there and show the rest of us your circuit or speaker design!!). What makes a speaker (or amp, cartridge, cable, etc.) good for one genre makes it good for another since we humans uses the same range of frequencies for music regardless of what the nature of the music.

Bose designed the 901 to mimic the concert hall, which might suggest to some that its better at classical music. It isn't. I regard it as a failure (insofar as accurate musical reproduction in the home is concerned; if meant to make money it seemed to be successful at that); at the very least there should have been more directly radiated information. The understanding of how the ear processes late delayed information was less understood back in the 1960s (if delayed about 10mS or more, the ear can use the rear-firing information for echo location, thus making the center fill more palpable; to do that the rear of the speaker needs to be at least 5 feet from the wall of the speaker behind it) when the speaker was designed.

I am thinking that the direction should be the lettering left to right with the beginning of the lettering facing out of the amp and the end of the lettering facing into the amp. Does this sound right?

@mitchb 

Not unless the fuses are in a DC circuit, and somehow have better conductivity in one direction rather than the other!

What people hear when they swap fuse direction isn't the fuse having 'directional' properties! Its a combination of the fit of the fuse in its holder (resulting in a lower voltage drop across the fuseholder) and expectation bias. The former is measurable (and slight), the latter is not.

It is impossible for a fuse to have a directional property in an AC circuit! That would cause it to favor one half of the AC power waveform and not the other- this would cause the fuse to heat up, since in the non-favored direction its resistance would be higher. Ohm's Law dictates this.

This would cause the fuse to heat up and fail, possibly within seconds of operation.

This statement is false:

Why a little wire makes such a dramatic difference I don’t know but it does. It has been proven by people’s experience. There are those who feel power products like cables and connectors don’t make a difference but they do. Not always positive I admit as everything is system dependent.

You can measure voltage drops across power cords and that can affect power amps that draw a lot of current (IOW they obey Ohm's Law). But its quite incorrect to say that this aspect of fuses is 'proven'. Its clearly not; I explained why. Further, I presented the explanation of why its actually impossible.

There are a lot of myths in audio, for example the idea that a certain speaker or amplifier can sound favor a certain genre of music. These myths exist in a viral form and infect in a way not unlike actual viruses. Once you disabuse yourself of them, you'll find that you can make greater progress on the sound of your system.