CVs blew fuses. - AVS Forum
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post #1 of 19 Old 11-26-2012, 04:04 PM - Thread Starter
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Receiver: Onkyo tx-8555

Speakers: Cerwin Vega RE-30s

I am sure the fuses are original and these speakers were made in the mid 90s. I was pushing the speakers today and simultaneously blew both fuses with the volume at about 70(out of 100). The lights were dimming as a result of the power draw.

Is my receiver just too much juice for these the speakers at that volume? Do old fuses blow more easily? Could the power fluctuation be the culprit?

I am having to amazon replacement fuses, so it will be awhile before I can get them up and running again.

Thanks for the help.
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post #2 of 19 Old 11-27-2012, 08:45 AM
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The fuses are there so the speaker voice coils do not overheat and burn up. You should be very happy that the fuses did their job and saved the speakers from destruction.

You need to turn it down.

The only issue is that you had it turned up too friggin loud. The other stuff you mentioned is nonsense.

Your hearing can be damaged in the long run if you don't.

Be sure that you use the EXACT model of fuse that was in there originally to properly protect the speakers. look at the marking on the original fuse and check the owner's manual.

If the lights were actually dimming, you DO have serious safely issues with your wiring that could cause a fire.This should NEVER happen!

One frequent problem is that expansion and contraction will loosen wire connections over time. check and tighten the wires where they attach to the circuit breakers, and also check and tighten the wires at the wall receptacles.
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post #3 of 19 Old 11-27-2012, 12:28 PM
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commsysman is right turn it down. cerwin vegas have been known to ruin foundation in the house. I like cerwin vegas also, but life isn't so great when you have no hearing. I am deaf in one ear. When you are young you want to play your music real loud. it isn't worth your hearing Johnny. johnny one guy blew out the glass on his fishtank because he had two cerwin vega 15 inch speakers next to it and a huge amp. I don't want your windows braking from volume 70 or your hearing. cerwin vega speakers have a high sound pressure level number that it will sound just as good at lower volumes.
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post #4 of 19 Old 11-27-2012, 12:59 PM
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Quote:
Originally Posted by keyboardcat View Post

cerwin vegas have been known to ruin foundation in the house.
johnny one guy blew out the glass on his fishtank because he had two cerwin vega 15 inch speakers next to it and a huge amp.
I don't want your windows braking from volume 70 .

Pretty dramatic, but perhaps overly dramatic. tongue.gif
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post #5 of 19 Old 11-27-2012, 02:01 PM
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ratman I have heard about cvs ruining foundation from several people and even a store manager many years ago at rex audio before it shut down.
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post #6 of 19 Old 11-27-2012, 02:07 PM
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ratman did your area get flooded bad from hurricane sandy or no? it is sad that so many people still don't have a home.
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post #7 of 19 Old 11-27-2012, 03:21 PM - Thread Starter
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Nice info. I wasn't actually in the room. I was using a remote through the doorway. It was definitely loud, but after years of dealing with junky brands lying about wattage it is hard to always know what accurate power readings will mean for SPLs.

I will have to look into verifying the destructive power of CVs. For me, even with dual 15s, the bass doesn't touch a single 12" sub.
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post #8 of 19 Old 11-27-2012, 03:23 PM
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^^^

ruining foundations is rather unlikely... as many of us are running enough subwoofage that if that was going to happen, we'd be collecting homeowners insurance... wink.gif

can't speak for ratman, but those of us in inland southern new jersey (we live in the same town) were very fortunate compared to many others... i was lucky to get off with merely an indoor swimming pool in the basement...

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http://www.avsforum.com/t/1332917/ccotenj-finally-gets-a-projector

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post #9 of 19 Old 11-27-2012, 03:35 PM
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if you want a powerful amp for them what about a crown xls 1000? it is light weight, but many people say that it pushes speakers hard. I never heard your cv series, but read good reviews about them.
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post #10 of 19 Old 11-27-2012, 08:32 PM
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Quote:
Originally Posted by JohnnyFriday View Post

Receiver: Onkyo tx-8555

Speakers: Cerwin Vega RE-30s

I am sure the fuses are original and these speakers were made in the mid 90s. I was pushing the speakers today and simultaneously blew both fuses with the volume at about 70(out of 100). The lights were dimming as a result of the power draw.

Is my receiver just too much juice for these the speakers at that volume? Do old fuses blow more easily? Could the power fluctuation be the culprit?

I am having to amazon replacement fuses, so it will be awhile before I can get them up and running again.

.

It would help if you gave the ratings of the fuses.
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post #11 of 19 Old 11-28-2012, 03:36 AM - Thread Starter
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post #12 of 19 Old 11-28-2012, 04:54 AM
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Quote:
Originally Posted by JohnnyFriday View Post

2.5 amps

The spec sheet says that these are 4 ohm speakers with a sensitivity of 97 dB/watt. Without any independent technical tests we don't know exactly how much of that can be depended on as both impedance and sensitivity are areas where speaker manufacturers often are less than perfectly forthcoming.

It is also possible that the speakers have lovingly cooked voice coils that rub occasionally and cause much greater current drains. The fact that the "The lights were dimming as a result of the power draw." is not a good sign.

Any music that blows 2.5 amp fuses in speakers this efficient is going to be LOUD! in most rooms.

I'm going to take the position that a more powerful power amp (which is easy to recommend) is not going to be a good move since you obviously don't have the kind of stable AC power that would allow you to fully exploit the amplifiers that you are using now.

The most productive way to get louder clean sound would be a very robust subwoofer that would offload both the existing speakers and the power amp driving them. I'm thinking something with a 15 or 18 inch driver and running a $grand or two from a supplier with a good track record for performance and value. SVS comes to mind but they have effective competition,
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post #13 of 19 Old 11-28-2012, 03:23 PM
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A 2.5 ampere fuse in series with a 4 ohm speaker?

POWER= current squared times impedance, so 2.5 squared times 4 ohms equals 20.25 watts.

That IS a going to produce a very high sound level with those efficient speakers...but it seems pretty conservative in terms of total power for those speakers. 20 watts applied to a speaker with 97 db/watt sensitivity will give 110 DBA, which is very ___ loud.

Are you sure that is the fuse size called for in the owner's manual??

I would think that those speakers are probably rated for more than 20 watts.

A 4 ampere fuse would allow 64 watts to be applied before the fuses blow.
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post #14 of 19 Old 11-28-2012, 05:33 PM - Thread Starter
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I am sure that was the fuse size as the clasp holding it states to use only 2.5 amp fuses. 110 DB? I am guessing it was getting close. Like I said, I couldn't be in the room with them, they were THAT loud. So, I used too much juice. No issue. The question is to get an equalizer or not. They always sound tinny to me, or maybe I am just spoiled with dedicated subs.

I dont know what It was like to listen to music on speakers like this back in the day with the receivers that were common at the time.

I paid 125$ for the pair, and the onkyo was cheap
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post #15 of 19 Old 11-28-2012, 05:43 PM
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Quote:
Originally Posted by JohnnyFriday View Post

I am sure that was the fuse size as the clasp holding it states to use only 2.5 amp fuses.

Counterpoint is that those fuse holders are probably 3AG size, which holds anything from less than a tenth of an amp to 20 amp fuses. The old fuses probably have their ratings stamped on the metal ends.
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110 DB? I am guessing it was getting close.

2.5 amp fuses don't blow instantly and can pass larger instantaneous peaks without blowing.
Quote:
Like I said, I couldn't be in the room with them, they were THAT loud. So, I used too much juice. No issue. The question is to get an equalizer or not. They always sound tinny to me, or maybe I am just spoiled with dedicated subs.

Subs are good and the right subs would be good for these if you want to shake the rafters.
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I dont know what It was like to listen to music on speakers like this back in the day with the receivers that were common at the time.

I paid 125$ for the pair, and the onkyo was cheap

Receivers have been stuck in a rut around 100 wpc for a long time. Before that 35 to 50 wpc was common and that's only a few dB less than 100 wpc. It takes 10 times the power to get the perception of twice as loud and consumer amps with 500-1000 wpc don't exactly grow on trees. If you want that kind of power you go to pro amps, which are just fine for music and home audio.
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post #16 of 19 Old 12-08-2012, 07:07 AM
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I had those same cerwin's back in college and had them in 3 different rooms over the years. All 3 locations the lights would dim when we were really letting loose on the volume. Those speakers had tons of output form the mid 30 hz range and up and we blew a lot of fuses. Eventually we got fed up and bought different fuses that wouldn't blow (not too smart but we didn't know any better) and then we could crank to our hearts content. We never damaged the speakers at all, they seemed pretty bullet proof. Years later I sold them and started my never ending search for my perfect speakers (well actually I think my search is finally over).

Anyway, I hope you guys are joking about doing damage to your foundation, my current system with dual submersive subwoofers has far more output than those cerwin's (especially down low) and there is no way in hell I'm doing any damage to my house.

Reading your post does bring back memories, the prime of my cerwin crankin' days were I around 96-98... wow time flies. smile.gif
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post #17 of 19 Old 12-12-2012, 02:52 PM
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sounds like your amp ran out of steam and clipped which took out the fuses
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post #18 of 19 Old 12-13-2012, 05:25 AM
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Quote:
Originally Posted by videodoktor2 View Post

sounds like your amp ran out of steam and clipped which took out the fuses

Unlikely to be true given that the fuse blows at around 20 watts, and the amp being used is easily capable of 5-12 times that much power.
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post #19 of 19 Old 12-21-2012, 11:08 PM
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The Cerwins used slow blow fuses. 2.5A @ 4 ohms = 25W, but bear in mind that'd be continuous power. 25W continuous power and the slow blow fuse typically means you're going to be hitting them with considerably more program/music power before blowing the fuse.

My old Cerwin D9s used 2A slow blow as the standard fuse but a 2.5A slow blow could be used optionally, with caution.

Just because there is a knob doesn't mean you should turn it.
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