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This is how to blow an amp Answered

Try hooking a 1200 watt sub up to a 75 watt POS amp. It lasted for like 20 seconds and something blew and it all shut off. The sub is still fine though but damn now I need a new amp :( Any ideas? I wonder if I could build myself one?

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NachoMahma

10 years ago

. OK. I think it's time to regroup and take a fresh look at this - I'm starting to get confused. . Parts: 1 bass driver with dual 4 Ohm coils rated for 1200W, 1 cabinet, 1 amp rated 75W. Are you using any type of crossover or other circuit between the amp and driver? . Goal: maximum volume with little regard for quality. . . If the amp sounds good with another sub, the that leads me to believe that the problem is in the woofer - a bad coil or improper wiring are my first two guesses. . Try using just one coil. Hook a coil up to either channel (straight from amp outputs to driver; bypass everything else) and listen at about quarter volume. Now use the other coil and listen at the same volume. Any difference? If so, one of the coils is bad. . If it passed the first test, wire the coils in series, hook to one channel on the amp, and listen at quarter volume. If it sounds OK, then go ahead and roll the volume up slowy while listening for distortion. Rearrange the wiring so that the coils are out of phase (tie the +s on the coils together and wire the -s to the amp) and give another listen. Wired one way should sound clear and the other way "muddy." If it sounds better with the +s wired together, then your coils are out of phase - not a problem if you are aware of it. . Whew! Time for a break. Try this stuff and see what happens. . Oh! Where did you see the stuff about dual-coil drivers and "off beat" music not being compatible?

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PunkguytaNachoMahma

Reply 10 years ago

Okay all give those a try, I'm just a bit afraid to in case I blow something and can't take it back to them. When I said it sounded crappy, that's when I had it wired in parrelel to the amp (btw it's apparently rated for 300 W dynamically (Whatever the hell that means)). I changed it around to be series which makes my amp pretty damn hot and I have to turn it off once in a while but it sounds basically how the other one did except with a little distortion and not as loud. I'm not using a cross over, although the amplifier does have a limited crossover in it's circuits, but only through high level inputs, it doesn't seem to filter the ouput when it's hooked up via the rca input. I have a kenwood amplifier that is hooked up to this smaller 75 watt amp. The kenwood has a digital 10 band equalizer that works in real time (it's fun to watch) and I set it to cut off everything above 80hz, it works fairly well combined with the panel amp. I'll try testing the sub like you suggested but one thing I did notice is that the cone is very hard to move (when it's off) which I'm guessing is because of the heavy duty voice coils, the leads that come off the push terminals go straight through the spyder and it interlocks through the waves in the spyder, looks neat and definatly a far off design from anything I've ever seen. Might be why it sounds a little different. Now another thing, the excursion on this subwoofer is pretty much the same size as the other one, and the amp seems to be able to push it out to it's full length and it's not that loud, if I got a 1200 W amp for it would it be louder?

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NachoMahmaPunkguyta

Reply 10 years ago

> I'm just a bit afraid to in case I blow something . That's something I haven't noticed in you. heehee But I'm learning to deal with it. ;) . > 300 W dynamically (Whatever the hell that means) . Marketing mumbo-jumbo for "It has some reserve power." It can put out the extra power for very brief intervals. Always be skeptical of amplifier power ratings. They are usually shown as xxW @ 0.yy%THD (Total Harmonic Distortion). Some companies will use 0.01% and others will use 0.1%. And there are probably others schemes nowadays. Just make sure you're not comparing apples to oranges. . > cone is very hard to move (when it's off) . The coils should not have any effect on how hard you have to push to move the cone. This is determined by the suspension (the ring between the outer edge of the cone and the frame). The coil/core may be in a bind, which is a big problem. . > excursion on this subwoofer is pretty much the same size as the other one . Is the excursion (distance cone moves) the same or the size (diameter)? I don't think the human eye is sensitive enough to determine excursion, but I could be wrong. If the size is the same, then they should produce about the same amount of sound (depending on efficiency, enclosure, &c) from the same excursion. . > if I got a 1200 W amp for it would it be louder? . Yes. But remember, power:loudness is a log function - it takes 10x the power to get twice the sound. Ie, a 1200W amp is only twice as loud as a 120W one. For you, I highly recommend that you stay well below the speakers rated capabilities. . . For your system, I don't think you are going to be able to harm the woofer, no matter how you wire it up. Woofers, by their nature, are very rugged. They have large coils that can take quite a bit of heat. Tweeters and mid-ranges are a different matter. They cannot handle the DC encountered when an amplifier clips (causes the coil to heat up). . What you need to worry about are your amps. You are pushing them too hard from what I can tell. Not only do you risk your amp, but as above, you run the risk of burning up tweeters (when used). . . How about a lead to the stuff on dual-coil/stereo problems? I'd like to check it out and see if I'm wrong about it.

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PunkguytaNachoMahma

Reply 10 years ago

A link to how they're able to be wired?: One link I found

I don't think the core is binded/frozen or it would not move at all and possibly make some pretty sweet smoke. And maybe I'm just expecting too much from a sealed/ported enclosure (it was a sealed one until I cut holes in it). I wanna make a bandpass box but I'm too dumb to make one of those and the only thing I could figure out was a square ported box which do sound pretty good.

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NachoMahmaPunkguyta

Reply 10 years ago

. According to that link, I'm right about the dual-coils - "You can wire each voice coil to a separate channel of your amplifier, ..." - but wrong about the output impedance of modern car amps - "... most car amps are stable down to 2 ohms in normal operation, ..." I'd say there's a good possibility I'm wrong about home amps being 8 Ohm, also. They may go down to 4 w/o problems. Which is all in your favor! :)

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PunkguytaNachoMahma

Reply 10 years ago

I just googled that, but if you google "wiring a dvc sub to seperate channels" tell me what you find.

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NachoMahmaPunkguyta

Reply 10 years ago

. I've got a better idea: post the link(s) you are referring to.

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PunkguytaNachoMahma

Reply 10 years ago

It's in here .

"Sure Tim...You just use a Y from the Sub out of the main receiver to whatever input on the unit you're using to drive the sub. It is a mono signal being sent, its just being amplified by two amp channels. I think it is typically suggested to NOT send two amp channels to a single VC though."

"At least you were playing the same signal through both channels but still there is potential for damage."

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NachoMahmaPunkguyta

Reply 10 years ago

"it is typically suggested to NOT send two amp channels to a single VC" (my emphasis). My suggestion is to wire one amp channel to a single VC - two times.

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PunkguytaNachoMahma

Reply 10 years ago

But you did ask me where it said that you shouldn't wire each vc to seperate channels right?

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NachoMahmaPunkguyta

Reply 10 years ago

. Yes, and you answered me. I was pointing out that they were discussing a different situation - we are sending two channels to two VCs. . . Yes, there will be some "distortion" caused by the interplay of the two signals. But it is no different than if you use two speakers and stick a finger in one of your ears. The signals just get combined at the driver, instead of your ear.

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PunkguytaNachoMahma

Reply 10 years ago

One thing I just noticed when I pulled the sub out to clean the insulation out of the vents (it's old crap and the sub seems to pull it into the woofer) and I thought I had it wired in series, but it's in parrelel apparently (was I stoned?) and the neg lead was hooked up to the left VC and the pos to the right respectivly (both connected to the proper pos's/neg's but just the right one first) I swapped them and it sounds better or maybe I'm imagining things, was maybe out of phaze? And my amp gets hot now and I thought that was on a 2ohm load, now I know fire would result if I changed it. I tested the seperate vc's and they sounded fine. Guess I better start saving for a big huge amp huh?

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NachoMahmaPunkguyta

Reply 10 years ago

. If they are wired in parallel, that will present a 2 Ohm nominal load to the amp. At certain freqs, it will probably dip below 1 Ohm. All the amps I've seen run hotter, the lower the load - that's normal. It used to be a pretty good rule of thumb (here's another one) that if you could hold your hand on the car amp, it was OK - but that was with sub-100W amps, so it may not even rate a ROT nowadays.
. I'd run the VCs in series, but I doubt that is an acceptable solution for you. You're amp will be safer (and most likely sound clearer), but there will be less sound.
. There are limits to what an amp will put out and it looks like what you have just ain't gonna do the job. So, yes, time to start saving your pennies.

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PunkguytaNachoMahma

Reply 10 years ago

I think I finally blew the shit out of that amp I was using, it started making a noise in the background that sounded scruffy just like it did with the sub before it. I've got it hooked up to my Sony surround sound unit, with each vc connected to a seperate channel and I made a Y rca cable to balance the outputs from the left channel on my first stereo (re: tape out to EQ, then to sony). It sounds a lot punchier than it did with the other amp, I'm not gonna hurt anything am I? I haven't blown any fuses in the stereo @ 4 ohms so far, so far so good? I've got the left channel on the EQ that I'm using all muted down except the 30,60,120 bands.

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PunkguytaNachoMahma

Reply 10 years ago

Huh? I thought wiring it in series was 2ohms *opens google* ..... shit I need to stop smoking so much weed. So this is why my amp is so hot, and I guess I gotta re-wire everything to find out which way sounds better, series or parallel. What do you recommend? Probably in series until I get another amp (My bud finally called me today so I'll pm you later and let you know if I got the amp or not).

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NachoMahma

10 years ago

. As far as the amp is concerned, the W rating of a speaker is meaningless. All the amp cares about is impedance. . You need to learn what an amp sounds like when it starts clipping and back down on the volume when it occurs.

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PunkguytaNachoMahma

Reply 10 years ago

Well I wired the sub in parrelel (it has two voice coils) so the amp was supposed to see 2ohms, and I though it would maximise the power out of the amp and it was pretty loud, but I just was looking at it now, there's a like .1A fuse that blew, but I still didn't like how the amp made noise when it was turned up, even without music going. Did I overdo it with the ohms? I can wire it so the amp sees 8ohms (I think that's what it's designed for). These 150 watt amps I was talking about, could I use that? And hook each coil up to their own channel?

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NachoMahmaPunkguyta

Reply 10 years ago

. As a rough rule of thumb, home amps are designed for an 8 ohm load, car amps 4 ohms. These are nominal values, since the speaker impedance varies with frequency. The only amps I've seen that will handle a 2 ohm load are high-end audiophile units or for PA use with lots of speakers. . You should be able to run each coil with its' own amp. Wire one coil to the L channel and the other to the R. If it sounds "muddy" swap the wires on one coil. . The noise you heard, at volume, was probably clipping, but may have been distortion from the impedance mismatch. The noise at idle, I'm not sure about. . Listen to your system at quarter to half volume and notice how tight the bass sounds and how the high end is crisp but not harsh. When the bass starts getting muddy or the high end starts sounding "brittle" or harsh, back off a little bit.

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PunkguytaNachoMahma

Reply 10 years ago

It sounded great when I turned it up really loud. I think the amp is just wonky because I had it hooked up to a 8ohm alpine car sub (8 ohm car sub? weird huh) and it made the same noises, but I never blew the amp :p I'm just a little worried about running each coil on their own channel, because you know how some music is recorded in joint stereo (same output level in each channel) or true stereo which has different things recorded in each channel. The guitar on the left and the kicker drum on the right, like that eh? This won't hurt the sub will it?

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NachoMahmaPunkguyta

Reply 10 years ago

. Nope. That's what dual-coil drivers are designed for. . . An 8 Ohm car speaker is not that unusual - "As a rough rule of thumb"

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PunkguytaNachoMahma

Reply 10 years ago

You like your rough rule of thumbs don't you? I did some googling and some people were saying that you should never connect the separate coils to separate channels. Like what if I started playing a track where the balance was off or something and was just driving one coil, wouldn't that screw it up? Or if one side is louder than the other maybe? I'm know I'm being annoying but I don't wanna see it blow when I just got it. I'm thinking that at 60 watt a channel, that won't be enough to play it will it?

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NachoMahmaPunkguyta

Reply 10 years ago

. Well, it's been over a decade since I was into audio gear, so maybe things have changed a bit, but all the dual-coil drivers I've seen were sold specifically to get a mono sound from stereo input (common in cars when stereo FM came out; mid- to late-60s). At higher freqs, you may get some distortion, but it shouldn't harm the speaker - shouldn't be a problem with a woofer. . Here's another rule of thumb, the power a driver/speaker can handle has little to do with it's efficiency. Ie, at X Watts, a 10W speaker and a 100W speaker will make about the same amount of noise. Larger drivers/speakers do tend to be less efficient, but there are too many variables (cabinet design, impedance matching, &c) involved to say it's always true.

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PunkguytaNachoMahma

Reply 10 years ago

Okay, one more question then. If I fix up this amp I blew (I just need to get a new fuse I think) should I run the sub in a 8ohm configuration like the other sub was running through the amp? I guess that the 2ohms parrellel configuration I have it in now is too unstable with the amp and is why I blew a fuse (I hope that's all, should prolly use a volt meter on the speaker leads to make sure eh?). Say, one more thing, this amp, it had a little pot on the circuit board and when I turned it, it started adding almost a buzzing sound to the music. What is this thing for? I turned it back but I wonder if it has something to do with stability.

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NachoMahmaPunkguyta

Reply 10 years ago

> I guess that the 2ohms parrellel configuration I have it in now is too unstable with the amp . Probably. If you can, wire it for whatever the amp is designed for. An amp designed for 8 will work with 4, but you'll get some distortion, especially at higher volume. AARoT, err on the high side - not as much sound, but much less likely to damage the amp. . > a little pot on the circuit board . No idea. Any markings near the pot? Wild guess: gain/attenuation pot.

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PunkguytaNachoMahma

Reply 10 years ago

I can wire it for 2ohms and 8 ohms but sadly it can't be done into 4 ohms, ironic as the fact is that the voice coils are 4 ohms each (laws of physics are so damn weird huh). I'm gonna wire it into 8ohms until I get an amp that will handle 2ohms, or is there a way to get 4 ohms? 4 Is basically the happy medium point, 2ohm runs the amp too hot and 8 is more stable but quieter from what I was able to figure out from the heap of crap googles could tell me. The pot if it was gain, wouldn't the signal go up and down when I turned it? Instead it made it kinda fuzzy sounding, but it had a more electric sound to it than just a fuzzy backnoise. Hard to explain but that's the best I can do.

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NachoMahmaPunkguyta

Reply 10 years ago

. If there was a 1/10A fuse installed, then a 8A will provide ZERO protection. You can just as well use a copper rod. I recommend 1/4A max and that's probably too big. The physical size of the fuse is unimportant, as is the voltage rating (as long as it's > 12VDC in this case). And it probably needs to be the fast-acting (quick-blow) type, but I could be wrong about this. A fuse on the outputs would be a slow-blow, but it would be much larger than 1/10A.
. I'm a bit confused about this, can you provide a wiring diagram of some sort? If the coils are 4 Ohms, then in series that would be 8 Ohms and in parallel it would be 2 Ohms (it's not that weird). But all you should need to do is wire one coil to L and the other coil to R - there shouldn't be any "tricky" wiring involved.
. Most modern amps, even if designed for an 8 Ohm load, will handle 4 Ohms if you don't crank the volume up.
. BTW, when I say speaker that's the enclosure, crossover, and drivers; a driver is the thing that actually makes the noise and most ppl call a speaker.

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PunkguytaNachoMahma

Reply 10 years ago

My bad, I missed this post. This is a 120V amp not a 12V car amp, but I'll be borrowing one of those hopefully tommorow. A wiring diagram, well I can link to one: DVC Wiring Diagram

I know my amp would probably handle a 4 ohm load fine, my sub amp only has one output though and both the coils hooked up either way result in either blowing the fuse (well I'll melt it next time due to my 9A fuse XD) or having it at a rather crappy volume. It's wiring in parrelel right now but I don't like the way it sounds, and it's definatly not very loud, it moves the cone pretty good, but there should be shit rattleing like mad, and it doesn't shake the room that good, my 200W alpine was even louder and made things fall of my desk.

It's a 1200 watt sub, I want it to actually be able to harm me - that loud.

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NachoMahmaPunkguyta

Reply 10 years ago

. Oh! As far as the pot goes, I'm still lost. If the volume didn't change, that indicates to me that it's not for gain/attenuation. It may be some type of impedance matching adjustment, but that's just another wild guess. . What's the make and model on your amp? I may be able to dig up some info on it.

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PunkguytaNachoMahma

Reply 10 years ago

Well it's a Mirage amp, it came out of one of their shitty Mirage Nano subwoofers. The only part number I can come up with is 6XEE153ZZZZZ and google could only give me one link (sometimes google just SUCKS). It's supposed to be a 300 watt "dynamic peak" amp but 75 continuous. Now, I hooked it up to my old alpine sub when I put the 9A fuse in to make sure nothing else was blown and could potentially blow my new sub. It turned out fine, it sounded "alright" to me so I didn't think there was a problem with it. But when it's hooked up to my new sub, it doesn't sound very good at all, I'm only really hearing the high end bass and very little pant leg shaking bass, but it still goes loud. Also, as most amps do, they have a buzzing sound that the capacitors or whatever make, and I noticed when I turned the pot up, the buzzing would get quieter and you couldn't even hear it when you turned the pot up all the way, but then the sub sounds even more like shit. -I got the sub wired in series then to the amp, so it has a 8 ohm load (apparently) just like my alpine sub is 8 ohms (according to the back of the magnet) but why doesn't my new one sound any good? I'd like to try to run the sub in 4 ohm mode but I can't seem to do that when both the coils are connected together, either 2 or 8 ohms, got any other ideas? I'd try the seperate coil per channel thing but that's apparently how these subs get blown because dumb asses hook them up and there's two different beats on each channel, but both coils share the same motor so you can basically figure out from there how that would easily blow a sub. I'm going to be talking to a friend of mine he's got a car amp that I pulled out of his truck when we were taking it apart, I don't know if his sub was as powerful as mine but it was a 12 inch. I know it said XT4300 or something on the top, but in the case he doesn't lend it to me (he spent a shitload on it) then what else could I use on a tight budget, the store I got this damn sub from wants like $350 moolas for like a 600 watt car amp or something dumb like that, no way, the same store that sold me a 1200 watt sub for $69 and then asks 100's for a amp, bullshit. Anywho I'll let you know tommorow if he's gonna let me use this thing or not.

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PunkguytaNachoMahma

Reply 10 years ago

I just bought a pack of fuses for my amp today, they're 9amp, I can't even find where I put the .1A fuse that came out of it. But yeah 9A is all I could get, it should still work fine as long as I don't push it too hard right?

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maninamousesuit

10 years ago

What i really want to know is were you playing lamb of god or van halen or were you doin that country thang? I would be terrible street cred suicide if you blew an amp while doing "Stand by your man"