why is a 5W tube amp louder than a 20W SS amp

[RogerMexiko]

Re: why is a 5W tube amp louder than a 20W SS amp

Repeat after me: Watts are a unit of power. Decibels are a unit of sound pressure. There is no function directly linking the two.

Now say it to yourself 10 times.

10 X (Watts are a unit of power -that are converted by the speaker in to sound pressure at increasing levels based on that power fed to them - Decibels are a unit of pressure - the measurement of this pressure has a relationship to the amount of Watts/power fed to the speaker by the amplifier.)

Did I do good?

 

[RogerMexiko]

Re: why is a 5W tube amp louder than a 20W SS amp

remember kids you must always take on mind your speaker's efficiency, or else you could brought you 100watter amp with a 4x12 loaded with 90db efficiency speakers and totally be stomped on by a guy using a 50watt amp 4x12 with 102 db speakers

Please see #37 "You have to have the same speaker, cabinet, room, placement, etc. I'm also assuming the exact same input signal was used at each power level." Kids

 

[EDX]

Re: why is a 5W tube amp louder than a 20W SS amp

i know, i was just making a final statement on how important speaker efficiency is for volume

 

[baron55]

Re: why is a 5W tube amp louder than a 20W SS amp

Wattage has nothing to do with loudness, but how much the electrical circuit consumes in power. But for years and years wattage was always associated with loudness.

Here is the deal with solid state and tube amps. Wattage output is measured buy how much harmonic distortion is allowed. Meaning how loud can you turn the amp up before it distorts. Setting a tube amp and a solid state amp at 20 watts with1 % harmonic distortion, they will be pretty much the same loudness. The output of amps is not how loud they can go, but how loud they can go with the least amount of distortion. That being equal they are the same loudness.

Solid state amps distort very fast and have more odd order harmonics, also heavy distortion on the transistors leaks DC current into the speaker signal path destroying speaker voice coils. (remember cranking SS amps and causing distortion burns out speakers due to DC voltage on the voice coils) Nobody ever dares turning SS up past distortion because it sounds terrible and destroys speakers.

Tube amps distort much much more gradually and produce more even order harmonics which are pleasing, many guitar players would be very surprised how much distortion is present in a clean channel of a tube amp. That thicker or fatter tone means there is quite a bit of distortion. The crunch and high gain tones people hear are massive amounts of distortion.

SO when you have a 5 watt tube amp louder than a 20 watt SS amp, the 20 watt SS amp is probably at 20 watts, and the 5 watt tube amp is probably past that but with pleasing distortion. Keep in mind this is an over simplified explanation. Tube amps also use output transformers which keep DC current out of the signal path even in heavy distortion. You ever notice how bass players are more likely to blow speakers, it is because most use SS amps and distort the power section causing DC current to be present on the speakers which destroys the voice coils.

One reason guys fry tube amps with power attenuators is because they take a 100 watt tube amp and run it into an attenuator and crank it, to get that tone they are looking for they don't realize the amp is actually putting out 150 to 170 watts in some cases damaging the attenuator and then the amp.

So wattage output in most amplifiers is measured as how loud you can go clean before significant distortion. Like others said speakers design etc has effects as well.

Fyrrette Amps (VHT) a while back actually measure the output of about 10 popular 100 watt tube amps and came back with real world measurements that were all over the place from 65 to 120 watts on all amps that were (rated) at 100 watts.

 

[RogerMexiko]

Re: why is a 5W tube amp louder than a 20W SS amp

"Wattage has nothing to do with loudness, but how much the electrical circuit consumes in power. But for years and years wattage was always associated with loudness."

You said that then went off in another direction without explaining your assertion. Is it just coincidence that my 85W Twin Reverb is louder than my 5W Champ?
Look at the graph that was posted, it appears there is some mysterious relationship between watts and loudness. Can this be explained away?

Thank you for the further clarification on the difference between output ratings (odd that you are talking in watts after saying they have nothing to do with loudness) for valve vs SS amps. I understand much better now the answer to my original question.

 

[baron55]

Re: why is a 5W tube amp louder than a 20W SS amp

"Wattage has nothing to do with loudness, but how much the electrical circuit consumes in power. But for years and years wattage was always associated with loudness."

You said that then went off in another direction without explaining your assertion. Is it just coincidence that my 85W Twin Reverb is louder than my 5W Champ?
Look at the graph that was posted, it appears there is some mysterious relationship between watts and loudness. Can this be explained away?

No unless your twin reverb was designed very poorly of course it is going to be louder than a 5 watt amp of any kind. All things being equal. A 20 watt SS and a 20 watt tube amp will be the same loudness at the same distortion output. The point is most guitar players turn their tube amps past the clean rated output therefore they are producing more power than an equivalent SS amp because they can't turn the SS amp into those levels without massive clipping that sounds terrible and possibly will damage speakers. Just like any one who has played a Trainwrek amp that puts out 35 waste clean, will tell you it is louder than any 50 watt amp they have ever heard. Why because that amps power is all in the upper mids which the human ear is most sensitive too. Wattage does not equal loudness. But a large wattage amplified has the ability to push more voltage into a speaker therefore increasing the speakers ability to produce sound. A more accurate way to describe how loud an amp is is in decibels. Which buy the way is how sounds levels are measured.

 

[RogerMexiko]

Re: why is a 5W tube amp louder than a 20W SS amp

No unless your twin reverb was designed very poorly of course it is going to be louder than a 5 watt amp of any kind. All things being equal. A 20 watt SS and a 20 watt tube amp will be the same loudness at the same distortion output. The point is most guitar players turn their tube amps past the clean rated output therefore they are producing more power than an equivalent SS amp because they can't turn the SS amp into those levels without massive clipping that sounds terrible and possibly will damage speakers. Just like any one who has played a Trainwrek amp that puts out 35 waste clean, will tell you it is louder than any 50 watt amp they have ever heard. Why because that amps power is all in the upper mids which the human ear is most sensitive too. Wattage does not equal loudness. But a large wattage amplified has the ability to push more voltage into a speaker therefore increasing the speakers ability to produce sound. A more accurate way to describe how loud an amp is is in decibels. Which buy the way is how sounds levels are measured.

Yeah, dB/sound pressure has been covered in this here thread. How would you propose amp makers rate their amps in dBs? No practical way I can think of. So we are sorta stuck with using watts with the understanding as you have explained of the variables involved.

 

[Myaccount876]

Re: why is a 5W tube amp louder than a 20W SS amp

10 X (Watts are a unit of power -that are converted by the speaker in to sound pressure at increasing levels based on that power fed to them - Decibels are a unit of pressure - the measurement of this pressure has a relationship to the amount of Watts/power fed to the speaker by the amplifier.)

Did I do good?

Now I'm curious: Did you ask the initial question to learn something, or are you looking for validation of your (ill-informed) pre-conceived notion? I'm beginning to believe it is the former, because you have repeatedly chosen to blatantly ignore people who have tried providing you with thoughtful and informed answers.

Good luck.

 

[GilmourD]

Re: why is a 5W tube amp louder than a 20W SS amp

The 2+2 was 3.9 seconds. That's still fast as hell even by today's standards, but a second is a big difference. Interesting comparison though, as horsepower is the (imperial) measurement of mechanical power, while wattage is the (SI) measurement of electrical power, and both can be misleading. In the case of the Veyron, only a fraction of the advertised horsepower is needed to accelerate that fast - the hundreds of excess horsepower is needed to reach its top speed of just over 250 mph because buoyant forces (like air resistance) are so great that a lot of power is needed just to overcome resistant forces. What you'd need for acceleration is torque - physical displacement of an object using applied force, and friction to prevent the wheels from slipping which would prevent all of the torque at the wheels from being transferred to the ground - moving the car. More force (force is not equivalent to horsepower), the faster the acceleration. That's why the 2+2 and Veyron look so wrong when just taking into account the weight and power, but make perfect sense when all factors are considered. Same with perceived volume and wattage - the results usually don't make sense when just looking at two measurements, but make absolute sense when all factors are considered.

Also, the way horsepower was measured in the '60s was different than today.

 

[RogerMexiko]

Re: why is a 5W tube amp louder than a 20W SS amp

Now I'm curious: Did you ask the initial question to learn something, or are you looking for validation of your (ill-informed) pre-conceived notion? I'm beginning to believe it is the former, because you have repeatedly chosen to blatantly ignore people who have tried providing you with thoughtful and informed answers.

Good luck.

I asked what seemed like a little question and now see that it is much more involved than I imagined. I have learned a great deal and thank those who have provided insight and knowledge regarding this question.
Unfortunately you aren't one of them. I don't need elementary school repetition exercises, particularly ones restating something that is incorrect. You might want to look up the definition of "former" or is it that you agree I asked the question to learn something? But thank you for trying.

 

[GoldenVulture]

Re: why is a 5W tube amp louder than a 20W SS amp

You probably need a steam powered amp.

 

[Securb]

Re: why is a 5W tube amp louder than a 20W SS amp

There is so much bad information in this thread I don't know where to start. Things like speaker efficiency have nothing to do with wattage. At that point, we are talking about decibels. You can have two same amps, and one will be louder with a more efficient speaker. That does not mean the wattage changes. Also comparing wattage to Hp or Dbs makes no sense. It would be the equivalent of comparing liquid measure to linear measure. However, if you want a Hp to wattage comparison here, you go.

If you have two identical cars (amps) both with 200 hp (watts), they will go the same speed (Db). Then put a trailer full of rocks on one and weight reduce the other by taking out the seats and unnecessary equipment. The weight reduced car will go faster (+Db). However, we did not change the Hp (watts) of either car.

More efficient speakers and other modifications (open back v. closed back) will make the amp louder. However, the wattage does not change.

 

[Jacew]

Re: why is a 5W tube amp louder than a 20W SS amp

Actually hp and wattage are same thing, just different unit: 1 hp= 746 w (or 0,746 kw)...

 

[Little Pigbacon]

Re: why is a 5W tube amp louder than a 20W SS amp

If anyone has an issue with anything I've posted in this thread, please speak up.

 

[Securb]

Re: why is a 5W tube amp louder than a 20W SS amp

Actually hp and wattage are same thing, just different unit: 1 hp= 746 w (or 0,746 kw)...

However, it does not apply to the OP's question. 5 watts is 5 watts in solid state or tube amps. Different amps seem louder for an array of reasons. It has nothing to do with the amp being solid state or tube.

 

[Prophetsnake]

Re: why is a 5W tube amp louder than a 20W SS amp

Watts are like horsepower in cars. In the 60's horsepower was real. The record 0-60 time had been 2.9 seconds, made by a 1961 Pontiac Catalina 2+2, until the Bugatti Veyron came through with 2.5 seconds. So in a 2 ton car with supposedly 300 to 400hp, you did 2.9, and in a 3500 lb car with 1000hp you do 2.5. Something is wrong there.

Well, yes. What's wrong is your data. In the 60s, the fastest road legal car was an AC Cobra and the 0-60 time was 5.9 seconds. The only things doing it in 2.9 ( or less) were dragsters. The limiting factor here isn't power in any case, it's tire adhesion.

 

[Myaccount876]

Re: why is a 5W tube amp louder than a 20W SS amp

However, it does not apply to the OP's question. 5 watts is 5 watts in solid state or tube amps. Different amps seem louder for an array of reasons. It has nothing to do with the amp being solid state or tube.

Correct, 5 Watts is still 5 Watts regardless of how the power is achieved. I believe what Jacew (and what I’m) referring to is the claim that a comparison between wattage and horsepower isn’t accurate. It is absolutely an accurate comparison. Watts is simply the MKS unit of power (defined as the change in work over the change in time - work being the dot product of force and distance). Horsepower has the same definition, but uses imperial units. If you really wanted to, you could convert an amplifier’s power rating into horsepower. It’s still a unit of power according to the physical definition. It’d be really stupid (50 Watts would be 6.71*10^-2 horsepower), but you could do it. I have no idea why the US tends to use MKS units for electrical applications of physics, but not for mechanical applications. It’s nonsensical, but that’s the point being made. Nevertheless, your assertion that horsepower doesn’t inherently tell you a car’s speed the same way an amp’s wattage doesn’t tell you the loudness is correct.

 

[Jacew]

Re: why is a 5W tube amp louder than a 20W SS amp

"An amp producing more upper midrange frequencies will sound much louder compared to an amplifier with the same exact amplitude amplifying just low frequencies."

I would like to add that low frequencies require more power to amplify, so amp with more low frequency response requires more wattage to be as loud.

 

[Myaccount876]

Re: why is a 5W tube amp louder than a 20W SS amp

"An amp producing more upper midrange frequencies will sound much louder compared to an amplifier with the same exact amplitude amplifying just low frequencies."

I would like to add that low frequencies require more power to amplify, so amp with more low frequency response requires more wattage to be as loud.

Yep, hence why so many bass amps and PAs are high powered.

 

[Jacew]

Re: why is a 5W tube amp louder than a 20W SS amp

Correct, 5 Watts is still 5 Watts regardless of how the power is achieved. I believe what Jacew (and what I’m) referring to is the claim that a comparison between wattage and horsepower isn’t accurate. It is absolutely an accurate comparison. Watts is simply the MKS unit of power (defined as the change in work over the change in time - work being the dot product of force and distance). Horsepower has the same definition, but uses imperial units. If you really wanted to, you could convert an amplifier’s power rating into horsepower. It’s still a unit of power according to the physical definition. It’d be really stupid (50 Watts would be 6.71*10^-2 horsepower), but you could do it. I have no idea why the US tends to use MKS units for electrical applications of physics, but not for mechanical applications. It’s nonsensical, but that’s the point being made. Nevertheless, your assertion that horsepower doesn’t inherently tell you a car’s speed the same way an amp’s wattage doesn’t tell you the loudness is correct.

The official unit for vehicle engine power has been kilowatt here in europe for 40 something decades (I think) and were still talking about horsepowers too.