Subs---Can the huge magnetic fields cause amp failure?

[JJkizak]

After reading posts from this forum I noticed people having problems with the amps in the subs and wondered if the huge magnetic fields could blow the finals by redirecting the electron flow? We used huge electro-magnetic coils controlling the electron flow in high power Klystrons (100kw power output)

while working on the Dewline.

JJK

[ZAKO]

They can stop my heart....Or even pull the fillings out of my mouth.

[CECAA850]

JJ, I'm sure there are some electrical engineers that will chime in, but anecdotally it seems it's not an issue. There are a tremendous ammount of manufacturers that use inboard amps with their subwoofers with no problems whatsoever. I think you are seeing a board that posts just about every aspect of speaker and audio concerns. Occasionally there is a concern with sub amps as well as hundreds of other issues. Basically, what I'm trying to say (with no scientific proof to back my claim) is that amps in subwoofer enclosures are probably ok. Carl

[ZAKO]

Are you worried about proximity of magnetic fields damaging speakers or the opposite????

[DrWho]

It shouldn't be a big deal at all...any current travelling parallel to the magnetic field doesn't even get affected at all. Current travelling perpendicular likes to get pushed to the side, but since the "wires" are stuck to the circuit boards, the wires aren't able to move when current flows through them. Also, the current keeps flipping direction 60 times a second so even a free wire would wiggle back and forth and not even by that much. Anyways, even though it tries to wiggle the wire, the wire isn't going to move and the forces in question are very small...i dare say the vibrations due to air movement and cabinet vibrations would be far greater in magnitude.

[WMcD]

If the issue is that the sub's power supply is creating huge magnetic fields, I can't imagine that is the case at all. The goal of a transformer is to keep the field confined to the core.

I suspect the problem with sub amps and their power supplies is that they're under-designed, or at least marginal. Just enought to keep up with the occasional big transient. You look at the plate type amps (the form) which go on a 200 watt sub and they are relatively light weight compared to a 200 watt monoblock. In the latter case, they are moosey.

Edit P.S.: One thing implied by the question is that the magnetic field radiated from the power transformer somehow zapps the final transistors in the amp. That doesn't happen because the transistors really don't serve as much of an antenna. Rather, I think that if there is a sudden failure of the power supply, there is a spike in voltage in the output within the circuitry. That could cook a lot of stuff.

If you were in the DEW system, I'd think part of the design issue was the extent to which electronics are effected by the very big magnetic pulse from a nuclear bomb nearby. DEW would be a target.

Also, doesn't the Navy have its VLF transmitters to talk to submarines worldwide, in northern Minnesota. I've seen aviation maps warning that compass headings can be effected. They're playing with some heavy duty fields.

I just point these things out because there is some science to the thought. But it doesn't happen in the little box pumping out bass in the corner as far as I can figure.

Best,

Gil

[JJkizak]

Gil:

You are well informed. I did liken it to the "E & EP" weapon and did so wonder. I really don't know how large the fields are in the subs and started to wonder if they did affect things in the amps as far as solid state finals. Seems that can be overlooked much like a lightning hit with huge transients. I also don't know how close in proximaty the amp is to the sub field. If the finals are sitting next to the magnetic field I think I would be worried. I was just curious if someone had some knowledge of magnetic field affects on solid state components.

JJK