software

Here's a thought.

If you put a cab under a combo then the physical size of the amp's sound will be bigger, making the volume appear to be louder. So, you should be able to run a cleaner signal because you don't have to push the amp so hard to get it to cut through.

However, by adding an extension cab you're also lowering the ohms running from the amp, so the amp is working harder to drive a bigger load. This would suggest (to me atleast) that the amp will break up quicker/quieter.

Which one is it?


Originally Posted by benjaturnerHere's a thought.

If you put a cab under a combo then the physical size of the amp's sound will be bigger, making the volume appear to be louder. So, you should be able to run a cleaner signal because you don't have to push the amp so hard to get it to cut through.

However, by adding an extension cab you're also lowering the ohms running from the amp, so the amp is working harder to drive a bigger load. This would suggest (to me atleast) that the amp will break up quicker/quieter.

Which one is it?

umm what?

if you run the output at 8 ohm, you run it at 8 ohm. no diference in power.
if you run it at 16 it's the same power if you got one speaker, 4 speakers or half a speaker. the amp's power doesnt change

what you are feeling is, more air and a bigger sound DUE to more speakers, not because the amp is louder

it's not healthy running two diferent impedances or use a 8 ohm cab on a 16 ohm output (other way around works, you get less power though) becauseyou will seriously damage the output transformer.

if you add an extention cab under your combo, it will make the phisical sound bigger (like you said) thus it will appear that it is louder, but it wont drive the amp more because of it

i hope i made some sense

if you run the output at 8 ohm, you run it at 8 ohm. no diference in power.
if you run it at 16 it's the same power if you got one speaker, 4 speakers or half a speaker. the amp's power doesnt change

No, of course more speakers don't make an amp louder, obviously!

What I'm saying is, I always thought by putting an 8 ohm cab beneath an 8 ohm combo you are actually running the amp at 4 ohms. This will make the amp work harder to produce the same amount of volume, despite the perception being that the amp is now louder due to the increased physical size of the sound.

Will this extra work from the extention cab cause the amp to break up eariler despite a lower volume needed to produce the same physial size of sound?

Get it?

You always send the same amount of power through the amp.... if it's put on 1,2 or 4 speakers doesn't interest the Head... it just sends it's power... same with the ohms...

Edit: The only difference is, that if you use more speakers, each speaker will get less power, so it may sound different cause of the the speaker break up...


Originally Posted by benjaturnerNo, of course more speakers don't make an amp louder, obviously!

What I'm saying is, I always thought by putting an 8 ohm cab beneath an 8 ohm combo you are actually running the amp at 4 ohms. This will make the amp work harder to produce the same amount of volume, despite the perception being that the amp is now louder due to the increased physical size of the sound.

aaaaah, yes. now i understand you.
yea, the amp will produce more power that way. actually, the output transformer will

Will this extra work from the extention cab cause the amp to break up eariler despite a lower volume needed to produce the same physial size of sound?

Get it?

no, the amp wont break up earlier AFAIK because you have a lower output impedance on it.
the amp itself works only with what it gets from the front. it all goes to the output transformer which transforms the signal from the tubes and puts them through the speakers..

i could be wrong though, but even if it causes the tubes to break up earlier, i seriously doubt it's a noticeable diference

I think the thought is....

With the extra speakers, to achieve the same volume as before, he can turn down some, hence not breaking up at the volume he once did.

So overall, adding an extention cabinet won't make any noticable difference to how much (perceived) clean volume I can get before the amp starts to break up?
You always send the same amount of power through the amp.... if it's put on 1,2 or 4 speakers doesn't interest the Head... it just sends it's power... same with the ohms...

Is this right? I'm pretty sure the amp can tell the difference between different ohm rated cabs. Otherwise there would be no point in rating cabs in ohms at all, as it wouldn't make any difference to the amp anyway. I'm not saying the amount of speakers will interest the amp, just the rating of the load. The amp will have to work harder to feed a lower rated load, surely?

Davey said something about this difference being attributed to the transformer and it not really showing much tonal difference through the speakers. This sounds plausible. So from this should I assume that buying a cab will make no difference to the amount of clean volume I can get from an amp, or will it increase? I think Davey saying that I certainly wouldn't get any less. Is that right?

Cheers for your thoughts,
-Benja


Originally Posted by benjaturnerWhat I'm saying is, I always thought by putting an 8 ohm cab beneath an 8 ohm combo you are actually running the amp at 4 ohms. This will make the amp work harder to produce the same amount of volume, despite the perception being that the amp is now louder due to the increased physical size of the sound.
Will this extra work from the extention cab cause the amp to break up eariler despite a lower volume needed to produce the same physial size of sound?
Get it?

The reason a cab's impedance is published is for matching purposes. That's what the output transformer is for (it's a different story w/SS amps). From the tubes' standpoint, as long as the cab is hooked up to the appropriate tap on the transformer, they don't know if it's a 4, 8, or 16 ohm load.
More speakers will give you better projection that will translate to greater perceived volume. Unless you're playing so loud that you're getting power amp distortion, your tone probably won't be noticeably cleaner at the same perceived volume.
HTH

More speakers = more quot;sound powerquot;. (All other variables being equal) Sound power is a term that you don't run into often. It's the total of the energy radiated by your speakers. Where as sound pressure (volume) is the level at a certain location relative to the speakers. More sound power will translate into more volume but more volume does not necessarialy mean more sound power.

Think about headphones. Sound power is next to nothing. Stick that sucker right up against your ear though and the volume can rip your head off!

So all things being equal... 8x12 vs.1x12. The full stack will have more sound power AND more volume potential.

The breaking up of the speakers is usually depending on the size of the speakers, a cab with 10quot; speakers will usually break up earlier than a cab with 12quot; speaker providing they have the same number of speakers. This is because of the wavelength of the lower frequencies have exceeded the diameter of the cone earlier in a smaller speaker, which could no longer produce the correct pitch, and distortion will result.