Who can tell me what happens when you use an amp head rated 8 oms with a speaker cab, w/ 4/12" speakers rated at 16 oms ???? Thanks.....
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8 ohms carries more power than 16 ohms.if there is a fuse either in the back of the head, or in the speaker cabinet,you'll probably blow it.DO NOT use a larger fuse, or you will damage the equipment.You can get most fuses at radio shack.
serious inquires only. If outside of service area , you'd better have something I can build/remodel when I get there, or I won't be staying long.I have bills to pay , and time is money.e-mail me your plans or set list, and lets get to work.I will record/play with you for free, as long as there is a project we can payroll in.This includes anywhere in the country, folks.See my construction pics , lake houses, kitchens,baths, room additions, new construction.I also build/repair/setup instruments.See bottom pics for custom dulcimers,mandolins,and banjoes.You will not believe the tone that can be achieved using simply seasoned hardwoods.(these are from cabinet scrap from the kitchens above).Look forward to hearing from you. B.C.Allen
It will run at half power ,this may be a good thing if you have a loud head ,some amps will blow up if you run them at different ohms ,so be careful
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#4412 by RhythmMan
Fri Jan 19, 2007 3:29 am
Fri Jan 19, 2007 3:29 am
A 16 ohm speaker with an 8 ohm head is an impedeance mis-match.
That means it's inefficiant. They both should drop the same amount of voltage for maximum efficiency.
The larger the reistance, the more voltage is dropped.
And, also, the larger the resistance of the speaker, the less current will flow through the speaker and amp.
Whatever amount of current is flowing through the speaker - is the same amount as is flowing through the amp.
If an 8 ohm amp is looking for 8 ohms resistamce in the speaker, and finds 16 ohms reistance instead, only 1/2 the current will flow, for any given volume setting.
Less current than normal through the amp - should be safe.
.
If the situation was reversed - say a 16 ohm amp into an 8 ohm speaker, then the amp sees 1/2 the resistance it expects; and there's nothing to stop the extra current from flowing through it..
And so - twice as much current flows.
That's a little like a short circuit. Some part of the amp will get hot, like a toaster wire. You can easily cook your amp that way . . .
That means it's inefficiant. They both should drop the same amount of voltage for maximum efficiency.
The larger the reistance, the more voltage is dropped.
And, also, the larger the resistance of the speaker, the less current will flow through the speaker and amp.
Whatever amount of current is flowing through the speaker - is the same amount as is flowing through the amp.
If an 8 ohm amp is looking for 8 ohms resistamce in the speaker, and finds 16 ohms reistance instead, only 1/2 the current will flow, for any given volume setting.
Less current than normal through the amp - should be safe.
.
If the situation was reversed - say a 16 ohm amp into an 8 ohm speaker, then the amp sees 1/2 the resistance it expects; and there's nothing to stop the extra current from flowing through it..
And so - twice as much current flows.
That's a little like a short circuit. Some part of the amp will get hot, like a toaster wire. You can easily cook your amp that way . . .
.......ok, this is what you SHOULD do: take the back off the cab, re-wire the 4x12 "series-parallel". If you have a multi-meter,(even a chepo 5 dollar one) it would be wise to check the ohm load of each speaker, (thats the omega shaped symbol),then all together the way their wired now.To get it series-parallel: on the left side of the cab run a wire from the negative (there is normally a + or - symbol stamped) of the bottom speaker to the positive (+) of the top. Then bring a wire, long enough to reach the jack, from the negative (-) of the top speaker and another one of the same length from the positive (+) of the bottom
Do the same thing, in the same way, to the right side of the 4x12.
Take the two negative wires and connect them to the negative side of the jack. That's the side that touches the sleeve of the 1/4" plug.
Take the two positive wires and connect them to the positive, or tip, side of the jack.
If you don't have a soldering iron, don't worry. Leave about a two inch piece of wire on the jack, strip it about an inch, do the same for the other wires, and BLACK tape it. Use 3M SUPER 33+ BLACK TAPE ONLY!!! Some may cringe at this, but this tape counts as insulation, and in the end you will have less resistance than solder.........really.
This will give you an 8ohm cab. Running the 8ohm head into a 16ohm cab will, to put it simply, fuk-up the head. Really. Try this trick, you'll be happy!
Hope this helps, hit me up if you got any questions [email protected]
Keep it Kill!
All you need to do would be to put two 16 ohms cabs in parallel. This would produce the needed impedance. Keep it simple, less chance of problems and you won't be taking a chance with bad modifications. Never use tape, a crimp on connector is much better than soldering also. If you do use a single cab, no problem, but you will experience a reduction in power of about half. ex. 400 watt becomes 200 watt. There shouldn't be any problem unless you go to a smaller impedance on the speaker cab. This will over drive your amp.
..........yea, all you have to do is buy another $700 4x12.........never use CHEAP tape on any connection. 3M SUPER 33+ is about $7 o roll. It is highly adhesive, and will stretch forever. Butt style crimp connectors can be fine, but you need to have a really good crimp tool, that combo tool that comes from the parts store is not a good tool. these connectors will collect moistiure, so they need to be taped after crimping. Always "tug" the connection after crimping, if the wires come out, it's bad 
. Wire Nuts will work well also, just don't twist the wires before you put the nut on. This makes a poor connection. Don't forget to tape it when you are done.
.......You should not be afraid to make simple mods to somthing, use common sense, and pay attion to details. It's easy, like changing a
. Wire Nuts will work well also, just don't twist the wires before you put the nut on. This makes a poor connection. Don't forget to tape it when you are done.
.......You should not be afraid to make simple mods to somthing, use common sense, and pay attion to details. It's easy, like changing a
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