Will a 60 watt solid state amp rated at 4ohms work with a 300 watt 4×10 bass cab rated at 8ohms?

For what it's worth - years ago I bought a 2 x 10" combo - and discovered I liked how it worked on my bass. Later I bought a 4 x 10" and for big shows now I have an 8 x 10". I can't see the point of changing what I like - but it is a bit scary on a festival stage to see the volume cranked around quite a way and still find it not loud enough!
 
rob aylestone said:
For what it's worth - years ago I bought a 2 x 10" combo - and discovered I liked how it worked on my bass. Later I bought a 4 x 10" and for big shows now I have an 8 x 10". I can't see the point of changing what I like - but it is a bit scary on a festival stage to see the volume cranked around quite a way and still find it not loud enough!
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I'm only putting this together for home use or maybe a jam night at a club so this will be more than enough for what I need. Some people I've talked to about this were acting like this was a bad idea but then my friend who is in a band says his guitarist has his amp on a bass cab and as long as I dont go below 4 ohms on the speakers, it will be fine and no harm will be done to the amp and since its a 4×10 cab, the volume will only be compromised a little. So if I want it on 4, turn it up to 4 1/2 or 5. Like I said. I'm new at this. I have always played with combo amps. I was just trying to get insight so I don't mess it up.
 
Neither that amp or cabinet is stereo, the label on the cab says the JACKS are parallel, that is for daisy chaining two cabinets to one amp, the cab's is 8 ohms mono, you should just use ONE speaker cable to hook the head to the cab.
 
Shaggu said:
Some people I've talked to about this were acting like this was a bad idea but then my friend who is in a band says his guitarist has his amp on a bass cab an
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Putting something together to experiment is what it's all about.

I suggest a guitar cabinet. Then use a crossover box with an extension cabinet. Channel the low freq to a bass bin type enclosure. Use a SS amplifier.

The infinite immediacy of the mosfets , coupled with the extended low response of the subwoofer, creates this awesome crisp thump.
 
If you use a dummy load 8 ohm, in the open parallel jack of the cabinet, this new 4x10 of yours is 4 ohms. FIXED!

Dummy load 8 ohm 100W resistor . $20..
 
.... and the point is to waste half of your volume heating up the dummy load? It's like putting two 100W lamps in your hallway and painting the glass black on one of them.

4 Ohms is pretty much nearly a short circuit. The amp is having to work hard. An 8 Ohm load takes the pressure off. How many of us have never twanged the guitar and got nothing? Turned the amp up to full and still nothing. Then realised the speaker cable is missing? With modern designs, no current flow is the least work your amp will do. Even the loud rockers with their Marshalls cranked up sometimes lose their audio when one of the crew trips over the cable and the jack pops out. They have been terrible stage connectors for ever! Amps don't fail for this. Dodgy jacks bodged with tape and broken strands of copper can short out - and THAT is the worst thing that can happen. Most amps can even stand that for a short period. They're built with metal heads in mind, not fragile angels.
 
LazerBeakShiek said:
If you use a dummy load 8 ohm, in the open parallel jack of the cabinet, this new 4x10 of yours is 4 ohms. FIXED!

Dummy load 8 ohm 100W resistor . $20..
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Why would you send half the power to a resistor? That certainly won't help the volume difference between the 8 ohm and 4 ohm load and is a complete waste of time, money and effort. Anyway, the impedance load on a solid state amp doesn't matter much, as long as it is above a certain impedance.

Also note that the actual volume difference will also be affected by the efficiency of the speakers, so there may be no volume difference at all.
 
LazerBeakShiek said:
8 ohm and 8 ohms is 4 total.

It is not a waster if you wanted the amplifier to see a total load of 4 ohms. The stated max spec on the amplifier was 4 ohms.
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Right, but half the power would be turned into heat in the load resistor, so you would only have half the power left to go to the speaker cabinet. What is the advantage?
 
This impedance thing always goes like this on EVERY forum. There is ZERO point trying to match impedances in this way, because speaker impedances are nominal figures - the real figure constantly changes with spectral content. Series/parallel theory does indeed enable optimum matching - but using resistors is completely crazy - as two of us have now said, half your available power is totally wasted. There is absolutely no point doing such a silly thing. Hanging an 8 Ohm speaker on an output expecting 4 Ohms, just means a bit less volume in practical terms, but the amps are not 4 Ohm amps, they have a minimum speaker impedance e simply because the almost dead short placed across the output is damn hard for an amplifier to drive into. Stick on a 16 Ohm speaker and it hardly notices it. Getting the impedances matched just maximises efficiency, nothing more. There are a few more subtle electronic things going on with amp/speaker matching, but they have virtually no impact on what we are describing. We are kind of making a simple subject far too complex. Good practice dictates checking the minimum impedance an amplifier can tolerate, and not going below it. If you go the other way, you won't notice anything bar volume.
 
In my world the ohm and wattage effect the sound. Those speakers are designed to react for a specific load. That load makes them operate/articulate correctly.

Also it is matching the safe specs for the amplifier. That is not wrong.

Next you are gonna say the speaker wattage doesn't matter.
 
The general guideline is that ohm ratings are minimums for solid state amps. If you double it you get 3dB lower volume. Since one is rarely driving their amp with the volume maxed (in a home studio situation) it's a simple matter of turning up. There might be some difference in tone, but it won't be drastic and it won't necessarily be worse.
 
Speakers ARE the load. They do not react to the amp, because the driving circuit reacts to the load on it's terminals. Speakers can have impact on amplifiers - back EMF from overshooting coils and damping factor, but the basic premise is that amplifiers should not be run into lower impedances than their design can cope with. That is it, in practical terms. A speaker that heavily loads an amp is bad - if - the amp cannot cope with it. Wattage is a pretty rough term to link to sound? Speaker designs can cope with practically any power level, but how they perform is not really a function of Watts - which is just a measurement of power. If you want a particular sound, then you can produce it. You can have a 10" speaker, with it's own frequency response, transient response and it will be totally different from a different 10" one. I view speakers as tonal products. I'm VERY happy popping my 8 x 10" cab on ANY of my amps, and I have a couple of heads - one loud, one modest. I'll swap these to any of the cabs, some combinations work better (for me) than others. On the 8 x 10", my sound man likes the second one down on the left for an SM57. Me? I don't worry about it. Any would do me. Guitar speakers with their coloured labels make me smile a bit - they're all pretty inaccurate devices and we're praising the change in tone each has as a 'feature' not a snag.
 
I totally wasn't trying to have an argument started. The cabinet is getting delivered Friday. I will plug it in an let you all know how it turns out. Thanks for all the help and info. I will definitely keep it mind on my next throw together experiments.
 
LazerBeakShiek said:
Those speakers are designed to react for a specific load. That load makes them operate/articulate correctly.

Also it is matching the safe specs for the amplifier. That is not wrong.
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The speakers don't react to a load, the speakers are the load. On a solid state amp, the load doesn't matter like it does on tube amps because they don't have output transformers.
 
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