[asianbacon]

Hey, i'm planning on buying my first half stack soon. I know that SS and Digital amps are ###### so i'm looking at tube stacks. I notice that watt level is different on heads and speakers. How does the sound level effected by, higher wattage (obvious), addition of speakers and etc.

[billy16]

I'll agree with you digital is crap, but solid state amps can be pretty good. Randall makes quite a few nice SS heads as does B-52. The Roland Jazz Chorus is a great example of solid state, though it's a combo. Tubes are not the end all of great tone. The sound is different, not always better.

As for wattage and speakers, speakers are always higher wattage than the amplifier can put out. The reason behind this is that amps actually are more efficient when they are distorting in terms of output power. That can be almost double what the amp is rated for, so you need speakers that can handle the wattage without damage. You'll also need to consider the amount of power you do have. You want to keep the number of speakers and the wattage in mind. You won't want to run a 15W head into a 4X12. You can do it, but it won't sound quite as good as if you used a 1X or a 2X. That is because you don't have a lot of power to work with and that power has to go between 4 speakers in a bigger cab instead of 1 or 2. Something else you want to be sure to remember is actual sound power. Any time you double your wattage, you only gain 3 decibels. Conversely, cut the wattage in half and you lose 3 decibels. So a 50W will only be 3 decibels quieter than a 100W, but that 100W will give you more headroom, more clean volume until distortion sets in. You don't really need 100W anymore. It's overkill for nearly ever application. With PA systems everywhere, you can get away with lower wattages. 15 up to 50W should suit just about anything. If you play music with distortion, consider a lower wattage that will distort sooner. If you need a mix, go with a midrange. If it's clean power you're after, go with the higher wattages.

Also the amount of ohms will affect the sound. You can run an 8 ohm head into a 16 ohm cab. You just lose some volume. But don't reverse that and try a 8 ohm head into a 4 ohm cab, you'll damage the speakers. Also with a tube head, your choice of tubes can also determine the volume of the amp as well.

[matt_theripper]

Also keep in mind that you dont NEED a half stack. You can gig perfectly well with a combo amp, which is cheaper and more portable than a half stack.

[Dave C]

Contrary to popular opinion, you're unlikely to damage a speaker by putting too many watts through it. Impedance is important, although most heads will run down to 4 ohms, but best to check.
The more speakers you add, the more overdrive you will get at a particular volume level.

[Fillmore_East]

I'll agree with you digital is crap, but solid state amps can be pretty good. Randall makes quite a few nice SS heads as does B-52. The Roland Jazz Chorus is a great example of solid state, though it's a combo. Tubes are not the end all of great tone. The sound is different, not always better.

As for wattage and speakers, speakers are always higher wattage than the amplifier can put out. The reason behind this is that amps actually are more efficient when they are distorting in terms of output power. That can be almost double what the amp is rated for, so you need speakers that can handle the wattage without damage. You'll also need to consider the amount of power you do have. You want to keep the number of speakers and the wattage in mind. You won't want to run a 15W head into a 4X12. You can do it, but it won't sound quite as good as if you used a 1X or a 2X. That is because you don't have a lot of power to work with and that power has to go between 4 speakers in a bigger cab instead of 1 or 2. Something else you want to be sure to remember is actual sound power. Any time you double your wattage, you only gain 3 decibels. Conversely, cut the wattage in half and you lose 3 decibels. So a 50W will only be 3 decibels quieter than a 100W, but that 100W will give you more headroom, more clean volume until distortion sets in. You don't really need 100W anymore. It's overkill for nearly ever application. With PA systems everywhere, you can get away with lower wattages. 15 up to 50W should suit just about anything. If you play music with distortion, consider a lower wattage that will distort sooner. If you need a mix, go with a midrange. If it's clean power you're after, go with the higher wattages.

Also the amount of ohms will affect the sound. You can run an 8 ohm head into a 16 ohm cab. You just lose some volume. But don't reverse that and try a 8 ohm head into a 4 ohm cab, you'll damage the speakers. Also with a tube head, your choice of tubes can also determine the volume of the amp as well.

Some of this is true. High end digital modelers sound very good. Not cheap amps like Cubes, Spiders, Vypyrs, etc. cheap amps, whether tube, solid state or digital, usually all sound bad.

The last part about running an underload will usually result in your tubes running too hot, it will not do anything to the speaker.

Contrary to popular opinion, you're unlikely to damage a speaker by putting too many watts through it. Impedance is important, although most heads will run down to 4 ohms, but best to check.
The more speakers you add, the more overdrive you will get at a particular volume level.

a 30 watt jtm45 cranked through a 40 watt cab resulting pair of blown celestion heritage greenbacks beg to differ.

the second part is just wrong. The more speakers you add, the less you are pushing each. The more you push a speaker, the more the speaker itself will break up.

[Dave C]

Contrary to popular opinion, you're unlikely to damage a speaker by putting too many watts through it. Impedance is important, although most heads will run down to 4 ohms, but best to check.
The more speakers you add, the more overdrive you will get at a particular volume level.

a 30 watt jtm45 cranked through a 40 watt cab resulting pair of blown celestion heritage greenbacks beg to differ.

the second part is just wrong. The more speakers you add, the less you are pushing each. The more you push a speaker, the more the speaker itself will break up.

I beg to differ. It probably isn't the wattage that destroyed your green backs. Distirtion is the biggest killer of speakers.

Secondly, The more speakers you add, the more you overdrive the amp.

This post has been edited by Dave C: 01 August 2009 - 04:30 AM

[Fillmore_East]

Contrary to popular opinion, you're unlikely to damage a speaker by putting too many watts through it. Impedance is important, although most heads will run down to 4 ohms, but best to check.
The more speakers you add, the more overdrive you will get at a particular volume level.

a 30 watt jtm45 cranked through a 40 watt cab resulting pair of blown celestion heritage greenbacks beg to differ.

the second part is just wrong. The more speakers you add, the less you are pushing each. The more you push a speaker, the more the speaker itself will break up.

I beg to differ. It probably isn't the wattage that destroyed your green backs. Distirtion is the biggest killer of speakers.

Secondly, The more speakers you add, the more you overdrive the amp.

Think, the less you push a speaker, the less it breaks up, and I'm talking about a speaker itself breaking up. Any overdrive coming from the amp itself is INDEPENDENT from the speaker. More speakers will not make the amplifier overdrive anymore, BUT if you push a speaker, then the speaker itself will break up and you will get some distortion from the speaker. Completely different, and independent from the amp distorting. The ONLY way a speaker affects what is happening in the amplifier is small impedance changes due to a speaker being a reactive load. The more speakers you add, the less each speaker is pushed, and the less breakup you get from each speaker.

Second...

A speaker does not "sense" that there is distortion coming from the amp or anything, it's a very simple case of having an amplifier putting out excess of about 50 watts (cranked) onto a set of speakers that are rated for 40 watts. Pretty much burning them up. Amps are not usually rated for their peak power, which is why a 30 watt tube amp can very easily blow out a 40 watt cab.

Would you agree that if you used too high a voltage to power a small light bulb that it would dissipate too much power and burn out very quickly? My point is that it's always safe to go at least twice the wattage of your amp, because there is no telling how much power your amp is putting out at full tilt.

This post has been edited by Fillmore_East: 01 August 2009 - 07:24 PM

[billy16]

The only real way to measure what an amp can do is to turn it up and measure it's output power. I've always been told to at least double the power and that's what I've done. I've never had speaker issues doing that.

Speakers do have a bit of a threshold, I can't remember the technical name for this, but when the speaker is out of travel that is where distortion from the speaker will set in. They have a sweet spot, just like a lot of other things. When you exceed that, they distort more. I've never lost a speaker to distortion that I know of. Perhaps Dave meant that speaker distortion will kill a speaker. Technically, he would be correct. Yet, the cause of speaker distortion would be too much wattage. When that speaker is driven hard, when it's out of travel, it is distorting. This isn't a bad thing. But push too much wattage and you'll get more and more distortion and cone movement. That can over time destroy a speaker. Or really fast. Depends on how much excess wattage you're using.

This post has been edited by billy16: 02 August 2009 - 01:06 AM

[Dave C]

Think, the less you push a speaker, the less it breaks up, and I'm talking about a speaker itself breaking up. Any overdrive coming from the amp itself is INDEPENDENT from the speaker. More speakers will not make the amplifier overdrive anymore, BUT if you push a speaker, then the speaker itself will break up and you will get some distortion from the speaker. Completely different, and independent from the amp distorting. The ONLY way a speaker affects what is happening in the amplifier is small impedance changes due to a speaker being a reactive load. The more speakers you add, the less each speaker is pushed, and the less breakup you get from each speaker.

Second...

A speaker does not "sense" that there is distortion coming from the amp or anything, it's a very simple case of having an amplifier putting out excess of about 50 watts (cranked) onto a set of speakers that are rated for 40 watts. Pretty much burning them up. Amps are not usually rated for their peak power, which is why a 30 watt tube amp can very easily blow out a 40 watt cab.

Would you agree that if you used too high a voltage to power a small light bulb that it would dissipate too much power and burn out very quickly? My point is that it's always safe to go at least twice the wattage of your amp, because there is no telling how much power your amp is putting out at full tilt.

Normally, distortion is achieved by the power amp section of the circuit, cliping the signal from the preamp stage. Hense the term overdriven.
If your getting distortion by overtaxing the speaker, then i'm not suprised that your distroying speakers.
Also your theory would mean it is impossible to achieve distortion at a low volume level. Which obviously it is,
Don't confuse Voltage(potential difference) with watts(power). And for the record it's actual Amps(current) that melts wires.

[Fillmore_East]

Think, the less you push a speaker, the less it breaks up, and I'm talking about a speaker itself breaking up. Any overdrive coming from the amp itself is INDEPENDENT from the speaker. More speakers will not make the amplifier overdrive anymore, BUT if you push a speaker, then the speaker itself will break up and you will get some distortion from the speaker. Completely different, and independent from the amp distorting. The ONLY way a speaker affects what is happening in the amplifier is small impedance changes due to a speaker being a reactive load. The more speakers you add, the less each speaker is pushed, and the less breakup you get from each speaker.

Second...

A speaker does not "sense" that there is distortion coming from the amp or anything, it's a very simple case of having an amplifier putting out excess of about 50 watts (cranked) onto a set of speakers that are rated for 40 watts. Pretty much burning them up. Amps are not usually rated for their peak power, which is why a 30 watt tube amp can very easily blow out a 40 watt cab.

Would you agree that if you used too high a voltage to power a small light bulb that it would dissipate too much power and burn out very quickly? My point is that it's always safe to go at least twice the wattage of your amp, because there is no telling how much power your amp is putting out at full tilt.

Normally, distortion is achieved by the power amp section of the circuit, cliping the signal from the preamp stage. Hense the term overdriven.
If your getting distortion by overtaxing the speaker, then i'm not suprised that your distroying speakers.
Also your theory would mean it is impossible to achieve distortion at a low volume level. Which obviously it is,
Don't confuse Voltage(potential difference) with watts(power). And for the record it's actual Amps(current) that melts wires.

Yes, and we're not talking about current here, because we're not talking about burning wires, I'm talking about smoking a set of speakers by putting out too much power onto a set of speakers that cannot handle that power. The light bulb was a bad example, fair enough. A better one is burning up a resistor that is dissipating too much heat (which occurs by placing too much current through it). I didn't want to use that example because most people, in the practical sense, don't use resistors everyday. But lets think of a speaker as a big resistor, why don't we? It's an approximation as a speaker is not a resistive load, but it's a good enough approximation. But you have a resistor (speaker) and you have an amplifier that is putting out a signal (current), and when this current hits the resistor, it turns into power that depends on the amount of current that you're running into it. Freshman college physics tells us that if you have 10V and you connect it to a 10 ohm resistor that is rated for 2 watts (thus you have 1A of current in this circuit), that you will be dissipating 5W of power. What happens? The resistor burns out. The same thing happens to a speaker.

Now....

Please explain to me how more speakers is going to result in more overdrive? Apparently the ones you've worked on function differently from the ones that I've worked on, because I've never heard of a speaker affecting how much overdrive you're getting from the amp. If you can explain this to me, then, don't be afraid to get technical, I'm quite competent grasping this sort of stuff and I know how all the components in an amplifier works. Of course I'm not an amp expert and a considerable amount of my knowledge of how an amp works is in the mold of physics and engineering rather than practical electronics for amplifiers (I need to get around to reading Gerald Weber's book). So if I've somehow overlooked where reality dictates behavior the deviates from classical physics (and it does, which is why carbon comp resistors are more favorable than a carbon film resistor despite both being resistors, and why mustard coupling caps sound different than mallory coupling caps despite both being the same value caps) that I've apparently missed that causes an AMPLIFIER, and again, I mean the amplifier, not the speakers here, to overdrive more when it has more speakers attached, then please, speak up, as I admit, I'm not really always too sure how electrical changes affects tonal changes. But based on what I know, the way a speaker/speakers will interact with the amplifier, is by acting as a reactive load which results in slight change in impedance which can affect the tone of an amp, but again, I don't see how this would result in the amp overdriving anymore with more speakers.

Either way, you did not read what I said correctly. I said that a set of speakers distorting is different from an amplifier distorting. I will even highlight this...

Any overdrive coming from the amp itself is INDEPENDENT from the speaker. More speakers will not make the amplifier overdrive anymore, BUT if you push a speaker, then the speaker itself will break up and you will get some distortion from the speaker. Completely different, and independent from the amp distorting.

You can get distortion FROM the speaker by pushing it, and it is the case where when you have less speakers (assuming they are of the same model, wattage, etc. etc.) that you get MORE speaker distortion. Again, this is speaker distortion, not amplifier distortion. But it still counts as distortion in your overall sound, and is a large part in the tone of any artist who used Marshall plexis in the '60s and '70s when they were most widely used with low wattage speakers that could be pushed very easily with powerful heads like the Marshalls.

edit: This entire discussion is based on your comment that it is unlikely to blow out a speaker by putting too many watts through it. Which is false, I have no idea how you can even argue this, speakers are rated for power handling for a reason, and if they weren't so, then they would never blow out. The ONLY cases where you could argue this is by saying that....

1) amplifiers do not put out more than their rated wattage, thus placing a 20 watt amp with a 20 watt speaker is OK. Which is not always true depending on the amp, go hook up a "30 watt" Marshall JTM45 to a very large wattage power resistor of the same resistance as set on the amp, plug in a signal generator and look at the trace on the oscilloscope. Use a signal generator and turn the amp up all the way and you will see that based on the output voltage, your peak power (which is dependent on the resistance of the load you have hooked up), will calculate out to be far more than 30 watts, in fact, it's pushing closer to 55 watts when running full tilt. So by placing that into a pair of 20 watt Greenbacks for an extended amount of time, WILL end up damaging the speakers. I don't even see how you can argue this. I have done this myself and have seen Marshall superlead heads that are rated for 100 watts, putting out in excess of 200 watts when cranked to 10. Which would obliterate, a single 4x12 rated for 100 or 120 watts. And thus very much necessitating the need for two cabinets if one were going to run low wattage speakers (like for example, vintage Celestions).

2) second case is by saying that speakers are capable of handling a little bit more than what they're rated for. And this is the more legitimate argument, but you made no mention of this. And whether or not, it is going to be safe putting a set of speakers with an amp depending on the fact that they can handle more than they're rated for is a test of faith that I do not advocate to ANYONE that I give amp advice to. Amplifier distortion won't do jack ###### to a speaker, the speaker does not "hear" that an amplifer is clipping, but distortion that would cause a speaker to be damaged comes from pushing a speaker too hard, which correlates to too much power being put on the speaker. When the speaker starts to distort, it means it's start to approach it's limit, as long as you don't go above this limit, then you can still get a nice amount of speaker breakup, which sounds very good for certain applications, but once you pass that (which again, comes from it's inability to put out more power than it's rated for) then you risk burning the speaker out.

Again, I'm not trying to be rude or anything, and I'm not trying to be a smart ass here, but trying to downplay the effect of a speaker putting out more watts than it can handle is very bad advice.

This post has been edited by Fillmore_East: 02 August 2009 - 03:27 PM

[Dave C]

Yes, and we're not talking about current here, because we're not talking about burning wires, I'm talking about smoking a set of speakers by putting out too much power onto a set of speakers that cannot handle that power.

So when you say 'smoking a set of speakers' , if you don't mean the coils ( made of wire ) melting, do you mean the cone has ripped, or what?

[Fillmore_East]

The voice coil, I thought you meant wire as in speaker cable, but, yeah, along those lines, too much current through the voice coil will cause it to overheat and yes, it will burn out.

Now care to explain to me how more speakers cause the amp to distort more? I'm really curious to hearing how this works, because I often feel like my JTM45 doesn't have enough gain and if I can get more gain out of it by adding more speakers instead of opening it up and modding it, I think that would be a safer option.

This post has been edited by Fillmore_East: 03 August 2009 - 11:02 AM