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Fuse Direction Fix

172.56.241.255
Posted on January 28, 2023 at 16:46:38
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 Some comments on another fuse thread made a certain sense to me.
Power coming to your gear is AC. This to ME means that if a fuse can be considered a directional sensitve device, that 1/2 the time it is wrong and 1/2 correct.
And flipping it won't help.

I HAVE THE CURE.

A pair of fuses Each of the 'correct' value. A pair of Diodes of sufficient current capacity for the device to be fused. Anode / Cathode of the diode face in OPPOSITE directions and in series with one fuse each. Each pair is now parallelled so the AC flows thru only one fuse at a time and in opposite directions.....
I suspect a very small capacitor here somewhere to 'deglitch' the device......Or maybe use some kind of FRED?

When listening for directionality? Change direction of BOTH fuses at once. Or maybe just test-away. But in any event, SHOULD a fuse be shown to be 'directional'? This should provide some relief and a way to check.
Too much is never enough

 

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Congratulations!, posted on January 29, 2023 at 12:45:44
amandarae
Audiophile

Posts: 2591
Location: So.Cal
Joined: November 30, 2004
 You just created a FW rectifier with a "fudge" capacitor!

 

Rectifier, posted on January 29, 2023 at 20:03:05
AbeCollins
Audiophile

Posts: 46291
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
Rectifying AC on the primary side of a power transformer is not a great idea. The power supply will no longer work properly.



 

RE: Rectifier, posted on January 29, 2023 at 20:12:23
Davey
 Yeah, but it wasn't a rectifier he described.

People not reading. People not understanding. Or both.
But, it was most likely just a troll anyways.

Dave.

 

RE: Rectifier, posted on February 3, 2023 at 07:11:26
sony6060
Audiophile

Posts: 1465
Location: USA
Joined: August 8, 2014
 You are being 'suckered' by placebo effect.

 

RE: Rectifier, posted on February 3, 2023 at 10:36:00
Davey
 I am, am I?
Good to know.
Thank you.

Dave.

 

RE: Rectifier, posted on February 3, 2023 at 11:29:48
gusser
Audiophile

Posts: 3649
Location: So. California
Joined: September 6, 2006
 Yes, two silicon diodes back to back are essentially a piece of wire with a 0.7 volt drop. Large AC solid state relays are made with two SCR's back to back as Triacs aren't made much over 10 amps.

But this is getting ridiculous. We are all worried about how pure a fuse wire is yet we propose to put a known and measurable voltage drop in the path?

Also keep in mind a diode has a current limit. Putting a 1N4007 in series with say a 5 amp fuse is going to be a problem!

 

RE: Rectifier, posted on February 3, 2023 at 11:55:15
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 Yes, current limit IS a real and big issue. Maybe first test on a low-current device. DAC? Phono preamp?

But won't this conduct thru only one leg at a time....and if a fuse is in series with that leg, make the directional nature of the fuse more apparent?

And yes, the voltage drop IS a problem and may be visible if you look at the output on a scope by some 'notching'?
Too much is never enough

 

It's not really a problem., posted on February 3, 2023 at 12:03:00
gusser
Audiophile

Posts: 3649
Location: So. California
Joined: September 6, 2006
 I actually use 25amp SSRs on my power amp sequencer. Can't have 6 large power transformers coming on at once. Yes there's a voltage drop and the SSRs do need some minimal heat sinking.

But I am hardly worried about a 0.7 volt drop at a nominal 115 volts. And these amps run about +/-55 volts on the DC rails so it's a 0.7v drop on the DC rails as well.

 

RE: Rectifier, posted on February 3, 2023 at 21:29:08
Davey
 The result would be something similar to crossover distortion in a Class B amplifier.
One diode turning on and the other turning off is not something that happens without a finite delay.

Since your premise is incorrect, there's no need to fabricate a highly flawed test to 'prove' it. Fuses do not have a "directional nature." Period.

Dave.

 

RE: Rectifier, posted on February 26, 2023 at 20:41:22
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 I don't believe in fuse direction being a big deal....or any deal....either.

But if testible by those who believe? they should do so if possible in as blind a fashion as possible so audible differences will be the indication....

And yes......I see what you mean about crossover distortion / 'finite' delay.......

In my panels? If I was concerned, I could eliminate half a dozen connections and the fuse in the CROSSOVER....on each panel. I've heard some persons use those ceramic, filled fuses instead of glass.....
Too much is never enough

 

Quick Study - why direction matters in an AC circuit, posted on June 15, 2023 at 07:30:32
geoffkait
 You're looking at it incorrectly. The direction of the "audio signal" in speaker cables changes direction on + and - wires continuously, at the rate of the instantaneous audio frequency. When the signal on the + wire travels toward the speaker terminal the signal travels in the opposite direction on the - wire. And vice versa. Only signals traveling toward the speaker produce changes in the sound (by interacting with the voice coil and speaker diaphragm. You can ignore the signal when it's traveling away from the speaker on either wire. This logic holds true for all wires in the system. Since wire is asymmetrical physically and electrically there are differences in sound depending on the orientation of both + and - wires.

 

RE: Quick Study - why direction matters in an AC circuit, posted on June 17, 2023 at 05:33:58
sony6060
Audiophile

Posts: 1465
Location: USA
Joined: August 8, 2014
 A fuse used on AC has no direction.

 

RE: Quick Study - why direction matters in an AC circuit, posted on June 17, 2023 at 07:18:23
geoffkait
 What evidence do you have to support your argument? That you read it on the internet?

 

RE: Quick Study - why direction matters in an AC circuit, posted on July 10, 2023 at 21:56:49
KanedaK
Audiophile

Posts: 2519
Location: Brussels
Joined: April 27, 2010
 Well yes, it does. It is SO obvious when listening: the wrong direction consistently sounds flat and dull. It's not subtle at all.

 

Direction of fuse in AC circuit, posted on July 11, 2023 at 04:06:39
geoffkait
 For the umpteenth time direction matters in an AC circuit because we only care about the signal when it's headed toward the speakers, downstream. When the signal goes away from the speakers (upstream) during the half cycle of alternation of current AC you can ignore it since it doesn't affect the sound. That's true for both the fused wire and the unfused wire of the AC circuit.

This should not be surprising since the AC wires themselves are directional. Thus, you'd be well advised that if the fuse is in the speaker the speaker cables and the internal speaker wiring should also be oriented in the correct direction.

What isn't necessarily obvious is how the signal coming into the speaker on + wire and - wire interacts with the voice coil and the permanent magnet of the speaker. That's an assignment for the reader.

 

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