capacitor wiring

[Colby]

If i use it on my bass amp do i have to have a fuse after it before it goes into the amp

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[ftgu 10+ year member]

I would only use it on your bass amp

 

[maylar 10+ year member]

Originally posted by Colby If i use it on my bass amp do i have to have a fuse after it before it goes into the amp

No.

 

[evo2k3 10+ year member]

yes you should fuse it. Who ever said no, think about what your saying. You should fuse after a power storage that expells power slowly (battery), but not after a power storage and can expell its power instantly? Not great logic there. Generally people set it up where its fused in a distro block. You still need the fuse within 18 inches of your battery as well.

 

[jlaine 10+ year member]

Originally posted by evo2k3 yes you should fuse it. Who ever said no, think about what your saying. You should fuse after a power storage that expells power slowly (battery), but not after a power storage and can expell its power instantly? Not great logic there. Generally people set it up where its fused in a distro block. You still need the fuse within 18 inches of your battery as well.

You are installing a capacitor incorrectly if you put a fused source in front of it. Think about what you are saying to do here - the source is fused, the feed is fused, the cap is supposed to be within 12" of the primary feed for the amp in question. If you put a fuse in, you create a current-limited, voltage dropping instrument into the primary feed. May as well not install the capacitor at all at that point.

It's common knowledge to NEVER fuse the capacitor line between the cap and the amp.

 

[evo2k3 10+ year member]

Originally posted by jlaine You are installing a capacitor incorrectly if you put a fused source in front of it. Think about what you are saying to do here - the source is fused, the feed is fused, the cap is supposed to be within 12" of the primary feed for the amp in question. If you put a fuse in, you create a current-limited, voltage dropping instrument into the primary feed. May as well not install the capacitor at all at that point.

 

It's common knowledge to NEVER fuse the capacitor line between the cap and the amp.

yes your placing in a limit.....the fuse ratings for amps are above the maxium power they need, but below the point where damage occurs. With your logic, the only reason to fuse the line at the battery is to protect your wiring? Then why are there fused distrobution blocks? your fusing the power source to matter what, yes you want that power flow from the caps, but protecting the circutry should always be the primary objective. For example, if my amp can effectivley use a maxium of 60 amps....and damage to circuts occurs at 85 amps, the fuse rating might be somewhere around 70-75 amps, i dont EVER want more than that 75 or so amps running through that amp. But the cap can still send all the power the amp needs.

 

[Savant 10+ year member]

Originally posted by evo2k3 yes your placing in a limit.....the fuse ratings for amps are above the maxium power they need, but below the point where damage occurs. With your logic, the only reason to fuse the line at the battery is to protect your wiring? Then why are there fused distrobution blocks? your fusing the power source to matter what, yes you want that power flow from the caps, but protecting the circutry should always be the primary objective. For example, if my amp can effectivley use a maxium of 60 amps....and damage to circuts occurs at 85 amps, the fuse rating might be somewhere around 70-75 amps, i dont EVER want more than that 75 or so amps running through that amp. But the cap can still send all the power the amp needs.

Actually, yes.. I'm under the impression that fuses are for WIRES (unless your amp is 'externally fused').. You run a 'fused distro' to protect the stepped down wires.. I mean, if you have 0 AWG from the battery with a 250 amp fuse, you don't want to step that down to 4 8 AWG wires to 4 amps without fusing.. that 8 AWG would start a fire pretty **** fast if it shorted and could **** 250 amps before the main fuse blew..

Fuses in the power system aren't for protecting the amp, as I understand it.. the fuses in the amp are for that..

That said, I don't know if fusing after the cap is a good idea or not.. I would think you might want to cause you could potentially drain the cap instantly which is a LOT more power than should be going anywhere (depending on cap capacitence).. but I can see not fusing there since the only current out is what's being asked for by the amp.. if you get a short after the cap, the juice will flow so fast through the main fuse that it would blow.. but the same applies if you short after the cap fuse.. *shrug* To that topic, I have no knowledge, but I can see both sides.. which is electrically/mechanically correct? got me //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[jlaine 10+ year member]

Originally posted by evo2k3 yes your placing in a limit.....the fuse ratings for amps are above the maxium power they need, but below the point where damage occurs. With your logic, the only reason to fuse the line at the battery is to protect your wiring? Then why are there fused distrobution blocks? your fusing the power source to matter what, yes you want that power flow from the caps, but protecting the circutry should always be the primary objective. For example, if my amp can effectivley use a maxium of 60 amps....and damage to circuts occurs at 85 amps, the fuse rating might be somewhere around 70-75 amps, i dont EVER want more than that 75 or so amps running through that amp. But the cap can still send all the power the amp needs.

You want to send whatever that amp demands during a transient burst. If it is pushed to it's maximum, the transient surge WILL be more than the fuse rating. That's common and quite fine.

You do NOT want a limit. You do NOT want a fuse. You do NOT want a cutoff.

The only reason to fuse the line is to protect from fire. Not the amp, not the cap, not the distro block. Just to protect from fire. I never stated anything about fused distribution blocks, never were brought into the question.

You should never, never, never place a fuse between the capacitor and the amplifier.

 

[evo2k3 10+ year member]

i thought most class d amps where externaly fused? mine is...mabey thats a misconception of mine. Savat--to answer your question, if you get a short after the fuse, there is no power stored between the fuse and the amp, therefore the short will blow the fuse and kill the power at the fuse before the amp....hope that helps.

 

[evo2k3 10+ year member]

Originally posted by jlaine You should never, never, never place a fuse between the capacitor and the amplifier.

I couldn't disagree with you more. Fuses protect the wire from a fire, but also protect the amp. I will leave use to disagree, I have presented my side....you have made some fairly bold statments....we will leave it to the thread starter to pick.

just to add a personal expierence, mine are fused after the caps and the fuse has never blown while the system is running, I dont think you can back up the fact that the amp will draw more than its fuse rating. Secondly, if you should NEVER fuse it, why have I seen professional installs where the caps go into a distrobution block and less than 2 foot of smaller wire to the amps (understanding that 2 foot of something like 4 guage wire can saftley handle as much as the 15-20 foot stretch of say 0 guage feeding it).?? You dont need to answer those quetions, just think about them.

 

[jlaine 10+ year member]

Originally posted by evo2k3 i thought most class d amps where externaly fused? mine is...mabey thats a misconception of mine. Savat--to answer your question, if you get a short after the fuse, there is no power stored between the fuse and the amp, therefore the short will blow the fuse and kill the power at the fuse before the amp....hope that helps.

What does class D have to do with this? I'm not understanding what you are trying to express.

If you are going to place a fuse on the line, it should be before the capacitor, not after. This is what I am trying to get at- this is what is trying to be said. Do NOT place a limiter or a voltage dropping source after the cap, it's defeating the purpose of it...

 

[MikeofTulsa Moderator]

i'll say im in agreence w/ josh on this one.....cause figure that u have a cap less than 12" from the amp......why on earth would u want a fuse between them??? be kinda useless.....

 

[evo2k3 10+ year member]

i was responding to savat.....and the thread asked about bass amps i think, i am assuming he ment class d.....anyways...i edited my last post --re read it please.

 

[jlaine 10+ year member]

Originally posted by evo2k3 I couldn't disagree with you more. Fuses protect the wire from a fire, but also protect the amp. I will leave use to disagree, I have presented my side....you have made some fairly bold statments....we will leave it to the thread starter to pick.

Not bold... correct. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Fuses were never designed to protect the amplifier, that is why they have internal regulation and monitoring. Fuses protect the source, and from fire - that is it. This has been common knowledge for a very long time. Sometimes they will protect the amp, but it's not what it's primary purpose is.

And I quote:

"NOTE:

For maximum benefit, you should keep the length of wire between the capacitor and the amplifier to a minimum. Anything (wire, distribution blocks, fuses...) between the capacitor and the amplifier will reduce the capacitor's ability to quickly supply the current needed by the amplifier. Of course, if you have multiple amplifiers and want the capacitor to benefit all of them, you'll have to connect it to the distribution block. "

From:

http://www.eatel.net/~amptech/elecdisc/capacitr.htm

 

[jlaine 10+ year member]

Originally posted by evo2k3 just to add a personal expierence, mine are fused after the caps and the fuse has never blown while the system is running, I dont think you can back up the fact that the amp will draw more than its fuse rating. Secondly, if you should NEVER fuse it, why have I seen professional installs where the caps go into a distrobution block and less than 2 foot of smaller wire to the amps (understanding that 2 foot of something like 4 guage wire can saftley handle as much as the 15-20 foot stretch of say 0 guage feeding it).?? You dont need to answer those quetions, just think about them.

Ohh I get a chuckle out of this one...

Mine have never been fused after... Why? Because I know it's pointless, and completely useless.

What do you think the "peak" rating on the amplifier is? It's what the amplifier is capable of creating during a transient burst. How do you think it acquires this power? Creates it out of air? If it creates 3kW, and it's a 1500Wrms amplifier, do you seriously think it can just sit and draw 120A and be over 100% efficient?

During transient bursts, it not only WILL draw more current than the fuse rating, it is CAPABLE of it. Not only is it capable of it, it is designed to do so. Not only can I prove it, I can monitor it.

Do you seriously think that fuse just instantly pops at whatever amperage it's rated for? Better question, do you seriously think that cap is helping you with the fuse in the way?