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fun! Ohms question


SoundwaveLove

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K, so i got a 2X10 SWR 8 ohms

and a 1X15 ampeg cab also 8hms

 

and a bassman 100 amp at 4ohms

 

 

here's my question, the SWR has an in and an out, is the in/out wired for parellel or series if i go out into the ampeg?

 

also the bassman has an out and an "ext. out". above those outs it says total load 4ohms. does that mean that each can out out into a 4ohm load, or that the outs of both must equal 4ohms?

 

 

would it be bad for the amp to run the 4ohm amp only the 2X10 8ohm in case i don't feel like bringing the 1X15 with me one day?

 

thanks

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Originally posted by SoundwaveLove

so bass cab outs are typically wired in parellel then?


i was told with some guitar amps you can damage your transformer if ohm load is wrong, that's why i was asking

 

 

You can damage the amp if your ohm load is less than the amp can handle. Generally, amps are rated at what wattage they can put out at certian ohm loads... Usually 8Ohm and 4Ohm, though many amps can go to 2Ohms.

 

I always get confused between series and parallel, but you'll want to run your two cabs together (bridged) at 4Ohms instead of splitting them.

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Originally posted by SoundwaveLove

i was told with some guitar amps you can damage your transformer if ohm load is wrong, that's why i was asking

if the load is too low, yes. running a 2-ohm load on a 4-ohm minimum head is bad, but running an 8-ohm load on the same head is fine.

 

although if the amp is all-tube, you can damage by running incorrect loads, high or low.

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Originally posted by SoundwaveLove

its all tube.


what should i do? not run it on 8?


damn i was just doing that



is there such thing as a dummy load? like something i could connect to the output to even off the ohms if i just wanted to use an 8 cab?

Yes, but why would you want to? You end up wasting power into the dummy load, and making the amp work harder than it has to, using up your headroom.

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Yes, but why would you want to? You end up wasting power into the dummy load, and making the amp work harder than it has to, using up your headroom.

 

 

 

i would want to so i don't have to lug my 2X10 cab to practice when i'm playing dub and not useing any treble or mid anyway.

 

you know so i don't have to worry about damaging my amp when i only have 1 8 ohm cab with me.

 

 

is there someone who can awnser my original ohm matching question, i'm only getting more confused here.

 

to match my 4 ohm output should i go direct out from my amp from the output and the ext speaker output into each cab, or I go Amp -> SWR ->Ampeg

??????

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To answer your question: it's fine to run that Bassman 100 into an 8 ohm load. All-tube amps are very forgiving of impedance variations, and I know from experience this particular amp is fine into 8 ohms. What all-tube amps don't like is infinite impedance....no speaker load at all. If there's no speaker plugged in, don't put any signal to the amp either, or better still, leave the amp off.

 

If you want to run the second cab, you can either plug the second cab into the 'ext' jack on the back of the amp (it's parallel with the 'main' jack), or run it into the second jack on the speaker cabinet...cabinets are always parallel-wired if there are two jacks.

 

Two 8 ohm cabs in parallel = 4 ohm load.

 

Two 4 ohm cabs in parallel = 2 ohm load.

 

Two 8 ohm in series = 16 ohm load.

 

Two 4 ohm in series = 8 ohm load.

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