Alk es - networks coming soon

[PrestonTom]

RE: A fuse on the crossover

The problem with the 2 amp fuse is that the wire inside is too thin. One solution would be to use a fuse with a much thicker wire. Perhaps a 50 amp fuse would do the trick.

While we are at it. I noticed that the wire right after the connectors on the woofer ( I guess it is called the voice coil) is also very thin. Why not only is it as thin as the wire on that 2 amp fuse, what is worse is that it is very long. I guess if we are serious we need to replace that voice coil wire with something much more substantial. I am guessing a 14 ga voice coil might be sufficient, but we better be safe and replace it with a 12 ga version.

Or is there something that I am missing ....?

Good Luck,

-Tom

[Guest " "]

12 ga wire for voice coils...you will have to also replace the paper cone with a 25lb steel plate weight and use an auto rim as the speaker frame.

[D-MAN]

Here's whats happening with the fuse thing...

1) any change in wire diameter to a smaller diameter and/or differing metalurgy increases resistance. Resistance (heat) is what the fuse relies on in order to work, and that means it has a resistance to current "built in" to start with.

2) friction-mounted fuses have an air-conductor boundary with MUCH less-than 100% electrical contact per area. Any air-to-conductor boundary adds resistance, as well as being subject to issues of humidity, dust, air quality, etc. Add to that the nature of conductivity in the steel holder and the ends of the fuse, not so hot and it's not copper, so you are jumping current from one conductive element with a certain set of coefficients to another from a solder joint via a friction fit to another and then to a solder joint and back to copper.

Even so, simply replace the fuse with an short length of copper speaker wire (at least 12 awg; double it up if needed) and listen to the difference. That should get you started. If you have quality horns (like Klipsch, etc.), you should be able to tell.

3) additional solder joints (2) - you don't need them in the circuit, and the more solder joints in the circuit, the less conductivity, solder is not a 1:1 conduction compared to straight copper wire, but it's certainly better than a friction joint exposed to the air.

4) protect the woofer (that's where the fuse is) against what? Overdriving? Catestrophic amp failure? In 40 years of audio, this has never happened to me.

None of the other commercial speakers I have ever owned (ADS, Kenwood, SL, KEF) have fuses in them. If they don't need it, why would Klipschorns?

I think that fuses in the signal path are for PA and other high SPL work where fidelity is not the main concern.

Don't simply take my word for it, try it for yourselves. I don't want to hear from those who haven't tried it for themselves but want to argue about it anyway.

DM

[Deang]

I really don't know what to think about it, I've never really thought about it much before until now. I suppose if you measured the DCR and inductance of the coil with the fuse both in and out -- you wouldn't see any difference at all. As far as what happens under a load with varying frequency I have no idea -- I imagine we might not see any difference there either. I don't use them, it's bad enough that I have to use a resistor.

[D-MAN]

If anyone thinks they need a fuse, they probably should have one.

I am not a fan of fuses in the signal path, and I have my reasons.

Hopefully, someone will also test it for themselves and post their findings.

DM

[PrestonTom]

D-Man does raise one interesting point. The fuse does create another link where oxidation btween the surfaces might occur. This of course could become a problem. Every year or so I actually clean the contacting surfaces on my system (speaker cable ends, fuses, interconnects etc). Do others do this also?

-Tom

[BEC]

Ok, I have got you guys a bunch of data. Now you can analyze it and figure out whether D-man can hear the fuse or not.

ALK type A crossover measurements.

From input to woofer output impedance at 120 hz.

1.931 ohms.

Input to woofer output DCR.

0.623 ohms

Measurement across the woofer fuse holder with fuse in place, DCR.

0.263 ohms.

Assume that the woofer is 6 ohms in the bass bin.

You should have all the data to see how the fuse effects the signal in dB.

Bob

[sfogg]

Bob,

Is that a two wire or four wire measurement of resistance on the fuse

holder/fuse? If only two wire I'll see if I have a fuse holder/fuse

combo lying around somewhere and will do a four wire measurement.

Potentially one would also want to make a measurment with a watt or two

through the fuse to see how much, if any, that power has of heating

effects to its resistance and or impedance.

Shawn

[BEC]

Shawn,

Four wire with gold kelvin clips.

Edit: also, I did not remove the fuse first. It has been in place for years.

Bob

[BEC]

I have now removed the fuse and cleaned up the fuse and fuse holder. Really did not need it since both the fuse and fuse holder jaws were bright and shiny. Reseated fuse and took a DCR measurement across it again.

Got 0.255 ohms compared to 0.263 before removing the fuse.

Bob Crites

[BiggerIsBetter]

But you didn't tell us the relative humidity and elevation???

[sfogg]

Bob,

Thanks for the info.

Dana,

What amp are you using?

Shawn

[BEC]

But you didn't tell us the relative humidity and elevation???

My relative humility is "fair" and elevation is "stable"

Bob

[Al Klappenberger]

Guys,

CHEEZ! You are squawking about 0.2 Ohm in a circuit with many times that total resistance (and you are probably hooking up the speaker with bananna plugs that only make contact at the edges of each spring)! Even if you COULD hear the difference the fuse makes (and I say you can't), it is NOT worth a blown woofer that got blown becasue somebodys teen-age kid turnd up the bass thinking he could hear 20 Hz out of a LaScala!

Get real! The tiny resistance the fus adds is well worth it!

AL K.

[Deang]

No one here is "squawking", technically -- they are "woofing".

[sfogg]

Al,

Relax, I'm not saying it is audible or not. In my mind the audibility of it isn't proven at all. If one wanted to prove the audibility of it they need to pass a double blind listening test. Simply stating that it is audible vehemently is not proof in my book.

Until then I am just curious how that resistance in circuit *might* be effecting things. Though this is a bassackards approach. Proving there is an audible difference before going digging for reasons 'why' makes far more sense.

"You are squawking about 0.2 Ohm in a circuit with many times that total resistance (and you are probably hooking up the speaker with bananna plugs that only make contact at the edges of each spring)!"

And if one had an amplifier with an output impedance of .01 ohms into a 6 ohm woofer load the damping factor of the amp on the woofer is 6000:1.

Now you add .25ohms in between the amp and the woofer, in effect that raises output impedance of the amp. Now the damping factor of the amp to the woofer is 23:1. If the fuses resistance increases with power (it very likely does) the damping factor is going to get lower still.

One of the fairly well know tricks (maybe not known around here) of making a SS amplifier sound somewhat more like a tube amplifier is putting a 1 ohm power resistor between the amp and the speaker which in effect gives the SS amp a damping factor closer to that of a tube. Additionally how the amps output impedance (with the resistor) and a speakers that does not have a constant impedance interact to alter the frequency response (from a voltage dividor in effect being between the two) of the system is also well know.

Shawn

[oscarsear]

I put Al's ES crossover in 2004 Khorns in place of the AK-4. My initial impression was that the bass was almost overwhelming. Understand that my greatest complaint about the AK-4 was that it was too bright or bass light. Al's network really blossomed the Khorns in every respect. The detail, the sound stage...everything. I'll be interested to hear your response to the change.

[Dylanl]

I think sfogg comments are the most valid points I have heard yet (unbiased). I just wonder with the other weaknesses in my system if I would be able to hear a difference without it?

The ALK network was a huge step up from the AA I initially ran but I always wondered about the fuse in the design. The least resistance in the chain I have always heard is best. Correct me if I am wrong please.

I also do not have to worry about cranking the volume to blow a woofer so take the part of the argument out.

[Guest " "]

Here is a link which discusses calculating output impedance at the bottom of the first screen. examples provided, single ended=2.13 ohms, push pull=16 ohms, otl=16.5 ohms, yeah, you probally noticed these are only tube examples. What about SS equipment, not discussed at the link. If you have a tube amp, the measurable impact of a .2 ohm change in respect to output impedance takes on a different meaning since, especially for push pull and otl tube amps, the change is about 1/80th of the amps output impedance.

http://www.transcendentsound.com/amplifier_output_impedance.htm

My take on the fuse or no fuse question. My es400 have the fuse. I am using the default value that Al recommends. I can't seem to blow the fuse. I have tried numerous times. I mean I really tried to blow the fuse. I have about 200 watts to attempt it based on the amp's documentation. The sound level involved during this excersie was inhumane to the animals in my neighborhood. I am also using an amplifed sub-woofer that has an internal 400 watt amp, so I can't say the LaScala woofer is getting a traditional 20 - 400hz program band. The LaScala woofer is only getting 80 - 400hz due to the THX setting I am using. So maybe for active sub-woofer senerio's, the fuse on the woofer could be a review item.

[sfogg]

" the measurable impact of a .2 ohm change in respect to output impedance takes on a different meaning"

Exactly, that is why I asked Dana what type of amp he was using.

Shawn