DIY disaster. I recently made a pair of 12inch speaker cabs with a horn. Got a new amp today to test it on. Disaster.
Today I got my new Skytec Pro 600 amplifier. I know this puts out about 300W each channel and my speakers are 200W max, but I didn't actually drive the amp, I kept it under 2 on the volume dial, so low that not even the db meter was lighting up. However, when I was testing the amp with my iPod, suddenly, the right channel went silent with all db LEDs lit up so I powered the amp down, heard a pop from the right speaker, and that was it. The right channel never worked again. I replaced the cable, and tried a different working speaker on that channel but it just won't work. So I went back to the original speaker and opened it. It smelled a lot like magic smoke. I took the woofer out. It has blown somehow from under 20watts... The left speaker and channel works fine. The right channel is gone completely and so is my woofer. I'm gonna get replacements hopefully, but what could have caused this just so this doesn't happen again. For the record, the horns and crossovers in the speaker which blew still work, its just the woofer.
Today I got my new Skytec Pro 600 amplifier. I know this puts out about 300W each channel and my speakers are 200W max, but I didn't actually drive the amp, I kept it under 2 on the volume dial, so low that not even the db meter was lighting up. However, when I was testing the amp with my iPod, suddenly, the right channel went silent with all db LEDs lit up so I powered the amp down, heard a pop from the right speaker, and that was it. The right channel never worked again. I replaced the cable, and tried a different working speaker on that channel but it just won't work. So I went back to the original speaker and opened it. It smelled a lot like magic smoke. I took the woofer out. It has blown somehow from under 20watts... The left speaker and channel works fine. The right channel is gone completely and so is my woofer. I'm gonna get replacements hopefully, but what could have caused this just so this doesn't happen again. For the record, the horns and crossovers in the speaker which blew still work, its just the woofer.
Your amp failed and put out DC. The second speaker you tried is probably blown now also. The horn survived because of the cap in series with it. You may also have burned some of the coils in the crossovers.
Your amp suddenly developed a short and put out DC. Thats why all the LEDs lit up. The DC (probably full rail either plus or minus) burned out the voice coil in the speaker. It was not the audio power (AC voltage) that took out the speaker. An amplifier working properly does not put out DC. Do not reconnect any load until you resolve the DC on the output problem. Typical DC output on any amp is usually like .05 volts. Yours is much more than that!
I´d say large amounts of DC offset, but there are usually protection circuits that would turn off the amp, or disconnect the driver using an output relay. Also, the amp could be oscillating badly at HF frequencies, but this is more likely to fry the tweeter or crossover components. The woofer is likely to be the last thing to blow from HF. So in a way it doesn´t make much sense. My bet´s on DC offset.
Was this a brand new amp ? I wonder if there is anything load wise with your speakers that upset it (causing instability), although a commercial amp should be absolutely bullet proof and include DC offset protection. Tough luck 🙁
Did you use DC-blocking caps between the iPod and the amp? Hint: measure the DC-level of the iPod output. If the amp is also directly coupled, then your speaker unit is toast. I suppose the crossover did what it was supposed to, and let the DC bypass the horn.
Developed a fault? In a matter of minutes? And it blew one of my precious speakers? This is outrageous, good thing the woofer was a cheap crappy 15quid woofer. I'm pretty sure the crossover and horn is fine because it works fine on a hi-fi amp. The second one is fine, I think the right channel is disconnected, its not doing anything now no lights, fuse has probably gone. Is it safe to carry on using the left channel or should I save my second speaker?
Yes it was a brand new commercial amp 🙁
My speakers were 8Ohm, which is in the clear, the min is 4Ohm
Nope, I didn't know a such thing as DC blocking caps existed but I'm pretty sure the iPod is fine.
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Probably poor manufacturing. Don't use the other channel - return it for a refund.
Thanks for the info... I can't get a refund, it'll have to be a replacement, looks like I'll be staying with my old 15W Sansui AU2200 for now :/
Could I have caused this by connecting the speakers with musical instrument/microphone cable rather than using professional speaker cable? I think it might have been my fault cos in the manual, I'm meant to use proper speaker cables 😱
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Cheers for the tip. I might look into some loudspeaker DC protection to install into my cabinets but I just need them to work for now, cos my birthday's coming up and I want to have a disco.
Could I have caused it to blow myself for connecting the speakers to the amp with musical instrument/guitar/microphone cable rather than professional loudspeaker cable? They worked fine with my Sansui home amp :/
If you feel up to it, you could probably try repairing and/or recalibrating the amp. I have a benchtop power supply from the same company which, whilst not broken, I just wanted a schematic for the inside of it. I e-mailed the company (AVSL Group) and they sent me a circuit diagram without any hassle or fuss.
I would not trust an amp under the Skytec brand as these are usually just cheap, poor quality goods from China that are rebadged. I highly doubt that you did anything wrong and would blame it on poor manufacturing. Although my benchtop power supply is still working, the insides of it are not pretty believe me. Lots of sub-standard parts used and quite poorly calibrated so if this is anything to go by, I wouldn't expect much better inside their other products.
Jack
I would not trust an amp under the Skytec brand as these are usually just cheap, poor quality goods from China that are rebadged. I highly doubt that you did anything wrong and would blame it on poor manufacturing. Although my benchtop power supply is still working, the insides of it are not pretty believe me. Lots of sub-standard parts used and quite poorly calibrated so if this is anything to go by, I wouldn't expect much better inside their other products.
Jack
Oh really? I heard really good reviews about the Skytronic amplifier, and it was in budget at the time too. Well fingers crossed, I'll have to see what happens. I would have been pretty pissed if it blew an expensive Emience woofer, thank goodness I'm using a cheap Skytronic woofer.
But it did say in the manual DO NOT use guitar, musical instrument or microphone signal cable to connect speakers, and I thought that's what caused it.
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when you come to fit speaker protection fit them in the amplifier's case.
The protection can offer delayed turn on so that the amp switches on quietly.
It must have DC detection and auto disconnect if DC is high.
It must have line fuses in the two PSU supply leads to the amplifiers.
The protection can offer delayed turn on so that the amp switches on quietly.
It must have DC detection and auto disconnect if DC is high.
It must have line fuses in the two PSU supply leads to the amplifiers.
I think the amp already has switch on delay because I didn't hear the loud bang when I switched the amp on, just a click about 5 seconds after flicking the on switch. I can't actually open the amp to fit it inside the amp because of the warrenty, and opening it would void it. From what I read, DC protection is a requirement on all power amps, and is the amp's last ditch effort to protect itself and the speakers connected. In this case it's obviously failed. So if I can get a DC protection module, as I built the speakers, I will be mounting it into the cabs I think, I might need the warrenty if Skytronic are bad.
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If you had a short on the speaker lead that would kill the amp but unlikely to kill the speaker.
At least you recognised the speaker had blown, sometimes they partially blow giving a lower ohms reading than normal. Other times they go absolute short as the speaker coild fries and melts its insulation later.
Well I will be buying professional speaker cable now cos I'm scared... the smell of burnt voice coil isn't particularly nice either...
At the moment I'm using only the left channel with I speaker I don't care if I blow (its already has damaged cone), its working well at the moment but that could change soon. Still NO signal on the right channel. It's gonna have to go off for a replacement. If that didn't happen, this is actually a pretty nice amp, just wish it had bass/treble controls.
A mic cable might melt if too much power is put through it.
I tend to use 13 amp mains cable for my speaker leads.
Have you put a ohm meter across your cable to see if it is shorted ?
Its always nice to find what the problem was just in cae you get caught out again.
I tend to use 13 amp mains cable for my speaker leads.
Have you put a ohm meter across your cable to see if it is shorted ?
Its always nice to find what the problem was just in cae you get caught out again.
Are you using 1/4" jacks for your speaker connectors? I'm asking because you used "musical instrument/guitar/microphone cable". 1/4" jacks short out when you plug/unplug them, the metal ones.
I also had a Peavey Class-D amp blow up due to an open on the speaker wiring, it caught on fire and had to evacuate the hall.
I also had a Peavey Class-D amp blow up due to an open on the speaker wiring, it caught on fire and had to evacuate the hall.
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