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Tube Watts vs. Solid State Watts, Conversion?

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#62
Here's what has always raised my skepticism about this issue, every time it is discussed. There are more than a few tech geeks out there who are equipped to demonstrate what we are talking about (e.g., clipping performance, etc.) with hard data such as oscilloscope traces. Not one of them has ever stepped up to the plate.

If soft clipping is what gives a tube power amp its volume advantage, then someone should be able to show me what the waveforms look like, which support this hypothesis.
 
#63
lethargytartare said:
What I love is the fact that I've read many many many of these threads, and the vast majority of them are LOADED with misinformation, insults (typically against the OP), and justifications of the insults. I had the same question when starting out, and I DID read tons of threads -- more than even somebody listed here -- and found lots of useless crack-jabber and a fair dose of massive-technical-overkill for what could be a really simple topic.

Here it took about 50 posts before I saw the kind of info I THINK the OP would benefit from.

So, to the OP: I always heard it 3:1, and when I played my SWR 300w against an Ampeg V4B (100w), I found the two to be fairly competitive, so I kept 3:1 as my quick and dirty reference.

The way I heard the matter described that helped was this (and you can see this info in some of the latest posts in this thread): Amp watt ratings mean "watts before breaking up." SS amps break up near their max power, but sound like crap when they break up. Tube amps break up a lot earlier, but they sound really good for a lot of that range of breaking up. So tube amps end up with lower watt ratings, but seem to have a lot more power -- but that's only if you make the mistaken assumption that the "watt" means "maximum absolute power."

So, making up some numbers: my SWR 300 and Ampeg V4B might both actually have an actual maximum capability of 350 watts (before they blow up), and probably could be rated as 350watts. But once the SWR starts putting out 300 watts, it starts to sound awful, so anything after that is unusable. The Ampeg, meanwhile, starts to break up at 100watts, but sounds fantastic, so you keep cranking it. By the time it reaches a dangerous point, it's also putting out 300 watts -- glorious tubey growly whatever-the-F, and because of things folks explained earlier, it might even sound louder still than the SWR, but the key point is that the 100 watt Ampeg is keeping up quite nicely with the 300 watt SWR. So the reality is that this is all a matter of terminology (ratings) that are not explained to consumers in any meaningful way, unless you find a salesman who kindly boils it down to a simple practical (albeit not scientifically accurate) principle like "Tube watts are 3x louder than SS watts."

At the end of the day a newbie needs to know how to compare these amps if s/he's gonna make an informed purchase. Knowing how to compare SS amps to tube amps is a practical necessity, and delving into the finer points of compression and harmonics has its place, but so to does a simple discussion of practical principles -- and those are typically hard to find just by using the search feature.

If people keep asking the same question, it often means nobody has done a good job of ANSWERING it...

ltt
Click to expand...

Thank you again for understand that it can be frustrating to ask a question, and have a community go back to a war that has been marching from the beginning of time (or at least since tubes technology has been substituted in half of the bass amplification market with solid state technology)!

I never meant to pour salt in old wounds, but I did ask for information that I have not been able to find in other post. I think the quote above addressed my question in the most simple way possible, and I needed that. The other post referencing "even and odd harmonics" and clipping gets into where the volume and tone perception comes from. Which is also important information to have (and work to understand).

Thank you everyone for chiming in. Even those who felt in necessary to get a free jab in for their home team. This is the place to get all that energy/information out!:p
 
#64
My hybrid amp (tube pre and ss power) weighs 3.75 pounds and is rated at 600W.

Even if an all tube amp could be perceived to be "3X louder" than solid state and a 200W tube amp could match it my 600W hybrid in "percieved" volume, show me a 200W all tube amp that weighs 3.75 lbs and cost as much or less than my hybrid and I may consider going back to all tubes.
 
#66
I think it is funny that there is so much emotion involved in this topic.
"Tube guys" like me are fairly defensive about our beloved amps. OTOH the "watt is a watt" guys can not abide the idea that different amplifier topologies may behave differently. They are positive that a 300 watt tube amp isn't louder than a 300 watt solid state amp. I think they suffer from tube envy. I also wonder if they have ever owned a tube amp!
Here is a good analogy for me. Given the same horsepower which has more torque, a gas or diesel engine?

About that TC link, though it is from a manufacturer that is trying to sell you a solid state amp that is "as good as" a tube amp, I agree with what it says. It's pretty much what I have been saying (though not as eloquently) all along.
I still dont think any compression circuit can possibly emulate a tube amp. I own presonus, Summit and DBX compressors. They sound good at what they do, but I never think, whoah I got a one rackspace SVT there! I also own some TC digital audio plugins for my DAW. Their Tubifex is one of the better amp sims I have ever heard. And its almost 10 years old. So if anyone could make a fake tube amp I would put my money on them! But for the price of a TC bass amp I can get a nice used Mesa or Ampeg!
 
#68
Calaverasgrande said:
I still dont think any compression circuit can possibly emulate a tube amp. I own presonus, Summit and DBX compressors. They sound good at what they do, but I never think, whoah I got a one rackspace SVT there!.........
Click to expand...

actually, i don't know if you've tried one, but a Urei 1176LN emulates an SVT pretty darn closely.
i've used mine in the studio countless times and it definitely gets the the SVT 'vibe'. but of course, the 'catch' is, they cost as much as a whole SVT head.
 
#69
Calaverasgrande said:
I think it is funny that there is so much emotion involved in this topic.
"Tube guys" like me are fairly defensive about our beloved amps. OTOH the "watt is a watt" guys can not abide the idea that different amplifier topologies may behave differently. They are positive that a 300 watt tube amp isn't louder than a 300 watt solid state amp. I think they suffer from tube envy. I also wonder if they have ever owned a tube amp!
Here is a good analogy for me. Given the same horsepower which has more torque, a gas or diesel engine?
Click to expand...
which is louder: tube or diesel?

i used to have emotional investment in my gear. then i realized how pointless it is. i didn't build it, and people's negative opinions of what i like are totally irrelevant, so screw 'em. now i confine my emotional investment to liking how i sound through my stuff, and i actually listen to those who understand how the stuff works on a tech level because i know my ears are only good enough to understand what i like and not why i like it. and i don't have the engineering knowledge to argue intelligently.

if more people discussed this topic using intelligence instead of emotion, i think you would find your answers.

btw, whenever i've done my "scientific" volume tests with tubs vs. ss (plugging in, trying to match the tones as close as possible, and playing hard while turning up to the point of distortion), every single head that has been louder with clean volume has had more rated clean wattage regardless of topology. however, if they're already pretty close, the tube amp does seem slightly louder. not by much, though. it could easily be attributed to compression.
 
#70
First, some geekspeak:

"When an amplifier is unable to deliver required voltage or current, by using a sensitive oscilloscope at its output, we would see that the waveform peaks are clipped. This clipping, in turn, generates harmonic distortion. This harmonic distortion contains only odd-order harmonics if the clipping is symmetrical and even-order harmonics if clipping is asymmetrical. As a rule, all amplifiers when clipping produce both odd and even harmonic output. However, transistor amplifiers produce largely odd-order harmonics, while tube amplifiers produce largely even-order harmonics. All these harmonics increase in amplitude with higher degrees of clipping, resulting in more and more audible distortion of the audio signal. While amplifiers based on semiconductors, with increased odd harmonics, produce ear-piercing sound, many tube amplifiers, when driven above their capabilities, have so called "soft" clipping..." - Simon Thacher, Ph.D., Spectron Audio

We're not done yet:

"The way the human ear works is that it is very sensitive to the harmonic content of a sound. A tube amp is less linear (that is, has more distortion) at signal levels below clipping than a solid state amplifier. The distortion will increase slowly, and then more rapidly as the amp starts to clip. In fact, the distortion increases so gradually and is of such a benign nature that the onset of audible distortion has no easily defined threshold. The solid state amplifier on the other hand has no such gradualism. It is almost perfectly non-distorting right up to the point that it clips, and then it clips HARD. It's easy to hear the threshold.

"This sudden onset of distortion is also composed of relatively harsh sounding distortion, not like the subtle second and third harmonics of the tube amp. The human ear hears the sudden harsh distortion as clipping and harshness. It interprets the low order distortion of the tube amp as a louder sound, not as distortion. In effect, the tube amp fools the ear into thinking that its early distortion is more loudness. They therefore sound louder or more powerful than the actual measurements show are really there." - Guitar Effects Oriented website

And now, the translation into musician's terms:

"Tube amps are subjectively louder because they compress the signal when pushed hard." - our very own Bill Fitzmaurice
 
#71
Calaverasgrande said:
I think it is funny that there is so much emotion involved in this topic.
"Tube guys" like me are fairly defensive about our beloved amps. OTOH the "watt is a watt" guys can not abide the idea that different amplifier topologies may behave differently. They are positive that a 300 watt tube amp isn't louder than a 300 watt solid state amp. I think they suffer from tube envy. I also wonder if they have ever owned a tube amp!
Click to expand...

I don't think that anyone is saying that tube amps and ss amps are equally loud. They are just trying to explain why they are different apart and the reason isn't "tube watts" or "solid state watts". Actually, it seems that the guys who don't agree with the "watt is a watt" can not abide the idea that it is the different amplifier topologies that are causing the difference, not some "mystical" creation of "tube watts".

Calaverasgrande said:
Here is a good analogy for me. Given the same horsepower which has more torque, a gas or diesel engine?
Click to expand...

Not a very good analogy, but that's just the mech. eng. in me talking ;)
Well actually if torque would be the percieved loudness and horsepower would be watts then the "watt is a watt" guys are correct, because the torque difference is caused by other factors because horsepower (watts) ratings are the same for both engines. It's not the "diesel horsepowers" that create the difference.
 
#72
MNAirHead said:
Not being smartalacky.. just giving some first answer (so everyone can flame me wrong)

SSx1.35=tube sound

Totally different beast.. I play SS exclusively.. 2x200w heads and can pierce through a plexi.. as noted much of this is all in eq and spectrum setting.

I have some basses that alone will make a 50w combo amp out sound an SVT _ Pbass... not the same oomph.. just loud.
Click to expand...
If I guessed the amp in use was a MegaBass, would I be wrong?

Mike
 
#73
In regards to the original question:
Other than those working on amp design, or those interested in mental masturbation, what does it matter?
If you like a distorted amp, you would have to find the one that distorts the way YOU want it to.
If you like a clean signal, you would have to determine the power level required to drive a given speaker cabinet, to a given SPL. Then a decision could be made as to whether you prefer tube over SS sound characteristics. Just because you can't hear a tube amp distorting in a band setting doesn't mean it's not. BTW, a 300 watt SVT does not always offer enough power through an ineffecient cabinet for undistorted sound even at low volumes with high dynamics. Some Berg and Acme cabinets need more power for proper dynamics with a bit of headroom IMO.
 
#74
I don't think anyone is arguing that a tube amp and a SS amp sound the same (i use this term VERY loosely- probably closer to similar than same) at the same volume, but they behave entirely differently.

While yes, a 300w SS and a 300w Tube amp have the same watts, they do not produce the same amount of sound. Some of it has to do with the cab, see post above, but entirely if you get a huge cab and put 2 300w heads (one SS and one Tube) you will get more sound out of the Tube head.

Now if these statements are not basic enough.

A common and most versatile conversion is 3:1 or 2.5:1. This is varying through the type of head, impedence, cab, etc. but is generally a good rule to go by. I have a Bergantino HS410 (800w @ 4ohm) through and SVT-CL (300w) and it fills it up beautifully.
 
#75
JHorstmann said:
I don't think anyone is arguing that a tube amp and a SS amp sound the same (i use this term VERY loosely- probably closer to similar than same) at the same volume, but they behave entirely differently.

While yes, a 300w SS and a 300w Tube amp have the same watts, they do not produce the same amount of sound. Some of it has to do with the cab, see post above, but entirely if you get a huge cab and put 2 300w heads (one SS and one Tube) you will get more sound out of the Tube head.

Now if these statements are not basic enough.

A common and most versatile conversion is 3:1 or 2.5:1. This is varying through the type of head, impedence, cab, etc. but is generally a good rule to go by. I have a Bergantino HS410 (800w @ 4ohm) through and SVT-CL (300w) and it fills it up beautifully.
Click to expand...
you read the first post and just skipped right to replying, didn't you?
 
#77
JHorstmann said:
While yes, a 300w SS and a 300w Tube amp have the same watts, they do not produce the same amount of sound.
Click to expand...

That is true. Every tube head I've had has been louder than the solid state head, both with hum and crackling. Well, I suppose it also depends on the fan noise.

If we're getting all technical and stuff, I think the speaker cabinet actually produces the sound. The amp just gives it a signal :p

:hiding:
 
#79
JHorstmann said:
apparently you did because i've been replying the last 2 pages.
Click to expand...
lol...ok, sort of busted...i don't always read names.

anyway, i don't know how you could put up an argument stating "more sound with a tube amp" after reading this thread. "more sound" isn't exactly a scientific explanation ;) and that's why i assumed what i did.
 
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