Ever catch a Scumback on fire?
- Thread starter Higbean
- Start date
Doutorfunga
TDPRI Member
No, but I NEED to read your account of how you made it happen! 
Swirling Snow
Tele-Afflicted
I'm sure Jim has stories....
CV Jee Beez
Tele-Afflicted
I heard one blow up. It was a 65 watt M75. My friend plugged his Germino into a 1x12 loaded with it and it tapped out. I think it was a 50 watt head.
I like Jim and the speaker itself but, power handling is not their strong point. My buddy would plug the same amp into the same cab with a greenback and no issues.
I like Jim and the speaker itself but, power handling is not their strong point. My buddy would plug the same amp into the same cab with a greenback and no issues.
ahiddentableau
Tele-Afflicted
Scumback is pretty clear about how users are expected to be conservative with power handling. IIRC he comes right out and says he expects players to make sure their speaker ratings are double the published rating of their amp.
Chud
Poster Extraordinaire
I’ve always followed the convention of speakers being rated to handle at least double the wattage of the biggest amp I plan to use. I don’t think that’s specific to Scumback at all. It’s peak vs RMS
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Straight up, I'm not trying to bad mouth Jim or Scumback speakers. I'm 100% just trying to wrap my pea brain around things here.
18 Watt Marshall clone- Jim recommends a 65 watt speaker.
Marshall sold a bunch of handwired 1x12" combos with a 20 watt Greenback.
So what's the deal?
The 65 watt M75 sounds killer btw.
18 Watt Marshall clone- Jim recommends a 65 watt speaker.
Marshall sold a bunch of handwired 1x12" combos with a 20 watt Greenback.
So what's the deal?
The 65 watt M75 sounds killer btw.
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Chud
Poster Extraordinaire
I think it comes down to everyone being conservative in posting rms output/handling and not necessarily always posting peak. One handwired 18 w Marshall might put out 30-50w peak, another might put out 23-25w peak. A greenback is likely ok except at the extremes on the latter, but toast quickly on the former.
TheCheapGuitarist
Tele-Afflicted
I know very little about speakers, but it seems that they should be rated for the power they are actually able to handle. Otherwise the rating seems a bit arbitrary.
CirrusBand
TDPRI Member
I wonder if it depends on the design of the cone and the likely mode of damage. If it's easy for the coil to drive the cone beyond its excursion limits under certain signal conditions, then peak transients might be what causes damage. If the cone is heavily controlled and almost impossible to push too far, then sustained power overheating the voice coil might be what causes damage; the occasional transient spikes aren't going to be what blows that speaker.
Then you need to come up with a wattage limit that makes sense for two quite different speaker limitations.
Then you need to come up with a wattage limit that makes sense for two quite different speaker limitations.
tubedude
Tele-Afflicted
And to muddy the waters, many amp manufacturers are somewhat flexible in their wattage claims.
I've had good results using double the peak wattage as a rule. But I play mainly clean/warm. If I used heavy distortion, I'd up that to 4x the peak wattage. Voice coils dislike squarewaves.
kookaburra
Friend of Leo's
What Marshall sells and what Scumback recommends are two separate actions.
I did damage a 100 watt Scumback. In a 1x12 cab, it was a couple years old with some moderate use when I bought a Rockittretro 50 head. At that point I dimed it a number of times at the practice space. The speaker developed what I think was a damaged voice coil. At volume, it rattled toward the end of the note/chord decay. Still worked ok at low volume, so I gave it to someone who could use it that way.
I did damage a 100 watt Scumback. In a 1x12 cab, it was a couple years old with some moderate use when I bought a Rockittretro 50 head. At that point I dimed it a number of times at the practice space. The speaker developed what I think was a damaged voice coil. At volume, it rattled toward the end of the note/chord decay. Still worked ok at low volume, so I gave it to someone who could use it that way.
Sounds like a CYA thing for the guy that sells them.
Speakers are rated very conservatively across the board because many amps can produce transient peaks up to five or six times their rated power consumption.
Swirling Snow
Tele-Afflicted
From the loudspeaker's point of view, a 4x12 full of Fibreglas is a death trap. Heat kills. Guitar speakers are indeed excursion limited. That's why they compress. Most speakers fry from long-term heat build-up.
Scumback's customer base is often well-heeled and owns a boutique Marshall of some flavour. They're giving advice to people whose "50 watt" flame throwing hot rods do 79 watts.
But mostly, the concern is with the speakers that have paper coil formers. Those will burn. For the sake of being vintage correct, of course.
Scumback's customer base is often well-heeled and owns a boutique Marshall of some flavour. They're giving advice to people whose "50 watt" flame throwing hot rods do 79 watts.
But mostly, the concern is with the speakers that have paper coil formers. Those will burn. For the sake of being vintage correct, of course.
dan40
Friend of Leo's
@Higbean ...The paper voice coil (pvc models) are very sensitive to how much power they can take before burning up. Celestion's early speakers were made with paper voice coil formers but they eventually moved away from them as did many other manufacturers. Jim sells a lot of pvc models because people love the sound of those early Greenbacks but they are a bit more fragile than their standard models. He has also had customers damage speakers by pummeling them with a fuzz pedal at high volumes. The square wave distortion that a fuzz creates can easily overheat a voice coil unless the speaker has plenty of power handling capability in reserve. I think Jim is just being conservative with his recommendations because he sells so many of the pvc models.
