"Tube" watts....

[NOSValves]

Perceived loudness is not the same as measured wattage.

And yes, I know, but NOBODY measures wattage into a reactive load, do they? They use a fixed dummy load and nobody uses music as a source to measure wattage. That would be pointless.

DM

Were not talking about measured power were talking about percieved power playing music.

[NOSValves]

Why get an amp that clips "good" when you can get an amp that does not clip at all?

Because the amp that doesn't clip at all doesn't exist !

[D-MAN]

"Were not talking about measured power were talking about percieved power playing music."

Well, that's SPL in db's not watts!

Watts are electrical - Just trying to help you out here, bub.[]

DM

[sfogg]

Actually... what you said was...

'So a quality 20 watt AB Push Pull amp has the

ability to operate similar to a 40 watt class A tube amp

or SS amplifier "

Which is nonsense.

A quality 40 watt SS amp is going to still have dynamic headroom above its

steady state rating. So your quality 20w continuous tube amp... even if it has

'double' the dynamic headroom at best is going to be able to peak out at what

the SS amp is rated for continuous power. That SS amp will have dynamic

headroom beyond that point. If it has 3dB of headroom (a typical amount for SS)

that means 80w.

And then throw in a

reactive speaker where the quality SS amp will *double* is power output with the

halving of impedance (and the tube amp will at best have the same power... but

with higher distortion) and we can really see what happens.

Shawn

[Jeff Matthews]

Why get an amp that clips "good" when you can get an amp that does not clip at all?

Because the amp that doesn't clip at all doesn't exist !

I thought it clips when you're reaching max power output. Am I pushing anywhere near the 325 watts per channel at any point when I play my Crown real loud? I thought I was probably never clipping it.

[JJkizak]

Dman:

I am in complete agreement with you. Lets see now we have average watts, peak watts, RMS watts, music watts, even harmonic watts, odd harmonic watts, headroom watts, clipping watts, inflated watts, uninflated watts, "A" watts, "AB" watts, tube watts, SS watts, and "Whose on first watts".

JJK

[6foot8]

Remember PWK used at BGW 100 in his home. If I remember correctly it was because it had the lowest intermodulation distortion he had measured. I also remember hearing that intermodulation distorion is more of a critial metric than THD. Funny how he used a SS amp for that huh?!

By the way NOSValves I use all BGW (preamp and amps) in my home on my jubilees and you can come over anytime with that tube amp if you want and we'll see whatcha think 'bout how they sound. BGW is not cheap pro stuff that a DJ would use. I have studio quality gear that was hand made (back in the day) from his California manufacturing plant. I use all vintage BGW gear made when Brian Wachner was still alive, designing and making this stuff. It has all been refurbished to better than new by an excellent audio tech I know and it blows away anything else I have ever heard. It does not matter what type of music I am listening to, at 0.5% VU or 100%, it still sounds incredible.

By the way I live in the Orlando area so if you plan on heading to the beach or Disney let me know and I'll even cook some good filets for us...or maybe some crow []

[Deang]

"The place differences could be more pronounced is simply in FR if the speaker is a reactive load. The way the tube amp and the SS amp will deliver power to a varying impedance will be different which will alter the power delivered at different freqencies. IOW... the FR could vary between the two."

...and the lower the output impedance of a tube amp the more like solid state it sounds. At least, that's what I think. Even still, tubes always seem to sound cleaner somehow, and that characteristic applies regardless of topology.

I don't know Shawn, with the exception of only a few SS amps I've heard that I thought actually sounded relatively grain free, the great majority sound hashy to me. The exception to this are the little chip amps, which I think are very tube-like in an odd kind of way that I can't seem to nail down.

Craig, I'll take your challenge. I just need to find a low powered SS powered amp with 6dB of headroom (and then be able to pay for it:). I ran NAD in the early 80's, and I used to have a lot of fun putting the little 40 watter up against my buddy's 200wpc Dynaco at parties.

[m8o]

Good response. I see what you mean by the "odd" vs. "even" distortion.

As to the idea that some say tubes sound "bigger," I noted you stated that they would sound "bigger" under extreme conditions. I take it you mean when clipping. Correct?

I think Russell O. Hamm put it best in his famous paper published in the Journal of Audio Engineering titled "Tubes Versus Transistors - Is There an Audible Difference?" ... I must have read that paper 50 times in 1982 while attending engineering school, dreaming about how to use the digital signal processing of the time to 'simulate' the 'tube sound'. I highly recommend you read all three pages of the whole article re-published here @ Butler's site:

http://www.butleraudio.com/tubesvstrans1.html

I'll quote the most relavant to this discussion.

"

.

.

.

SIGNIFICANCE OF MUSICAL HARMONICS

Having divided amplifiers into three groups of distortion characteristics, the next step is to determine how the harmonics relate to hearing. There is a close parallel here between electronic distortion and musical tone coloration that is the real key to why tubes and transistors sound different. Perhaps the most knowledgeable authorities in this area are the craftsman who build organs and musical instruments. Through many years of careful experimentation these artisans have determined how various harmonics relate to the coloration of an instrument's tonal quality.

The primary color characteristic of an instrument is determined by the strength of the first few harmonics. Each of the lower harmonics produces its own characteristic effect when it is dominant or it can modify the effect of another dominant harmonic if it is prominent. In the simplest classification, the lower harmonics are divided into two tonal groups. The odd harmonics (third and fifth) produce a "stopped" or "covered" sound. The even harmonics (second, fourth, and sixth) produce "choral" or "singing" sounds.

The second and third harmonics are the most important from the viewpoint of the electronic distortion graphs in the previous section. Musically the second is an octave above the fundamental and is almost inaudible; yet it adds body to the sound, making it fuller. The third is termed quint or musical twelfth. It produces a sound many musicians refer to as "blanketed." Instead of making the tone fuller, a strong third actually gives the sound a metallic quality that gets annoying in character as its amplitude increases. A strong second with a strong third tends to open the "covered" effect. Adding the fourth and fifth to this changes the sound to an "open horn" like character.

The higher harmonics, above the seventh, give the tone "edge" or "bite." Provided the edge is balanced to the basic musical tone, it tends to reinforce the fundamental, giving the sound a sharp attack quality. Many of the edge harmonics are musically unrelated pitches such as the seventh, ninth, and eleventh. Therefore, too much edge can produce a raspy dissonant quality. Since the ear seems very sensitive to the edge harmonics, controlling their amplitude is of paramount importance. The previously mentioned study of the trumpet tone shows that the edge effect is directly related to the loudness of the tone. Playing the same trumpet note loud or soft makes little difference in the amplitude of the fundamental and the lower harmonics. However, harmonics above the sixth increase and decrease in amplitude in almost direct proportion to the loudness. This edge balance is a critically important loudness signal for the human ear.

RELATIONSHIP OF FACTORS AND FINDINGS

The basic cause of the difference in tube and transistor sound is the weighting of harmonic distortion components in the amplifier's overload region.

.

.

.

"

That the 'basic difference is primarily related to the oveload region' is focusing too much on driving the amp hard to have them sound different IMO though. It ignores that transistors vs. tubes usually have very different slew rates and dampening factors, dynamic headroom, and frequency response to mention a few.

...Still, if you care about the subject I think everyone owes it to themselves to read the complete paper.

[jacksonbart]

Dumb question I sure, but cant help myself, ok so an SS amp with headroom is basically 'under weighting'/ realistically weighting depicting its watt out put as opposed to saying what its total watt capacity is? Hypothetically is two manufacturers were to produce the same SS amp, one driven by marketing would say its output is 160 watts (given 0dbs headroom) and one driven by a more realistic measure might say 40 watts (giving 6dbs headroom) would be the same?

[6foot8]

Thanks M8o,

Due to the efficiency of my speakers and the fact that all of my horns are driven by amps with at least 3-6dB of headroom, I see no reason that any of this really applies in my situation. My midrange and tweeter horns are rated at 50 watts RMS with a peak handling capacity of 200 watts (6dBs). My smallest amp is 100 rms (3dB on the tweeter, which will never see more than a couple of watts anyway) and then a 225 watt RMS amp on the midrange drivers which usually never see more and a few watts RMS. Clearly I am never even close to running these amps anywhere near their rated power.

Besides talk is cheap, all this psycho-babble is tiresome. Come on Craig make a trip to Florida and prove me wrong. Take the wife to Disney or the beach then spend a day listening.

[Jeff Matthews]

It seems to me that there is no such thing as a "tube watt." It is just a watt. You either like the way it sounds, or you do not.

That's what I was after.

So, now that that is out of the way, a more intelligent discussion of tubes vs. SS can take place. It seems the consensus is that the distortion created by tubes is of a different (even) order than the distortion created by SS (odd).

I noticed on the specs NosValves posted of the MK amps that the distortion percentages are substantially higher than the specs usually found in SS. I think it was along the order of 1% distortion in the tubes, whereas, we often see something like .05% in SS.

So, is there any science that compares 1% "tube" distortion to .05% SS distortion? Or is this topic beyond any meaningful scientific analysis?

Also, just out of curiosity's sake, why doesn't an end to the tube vs. SS debate come about by introduction of 300 wpc tube amps that have huge damping factors? Is there some technological limitations to cost-effectively implementing this with tubes? (i.e. you can pick up 300 wpc SS that's pretty decent for $1000, so why can't you pick up tubes for about the same price that deliver the same power?)

Or, vise versa, why don't SS makers implement SS that creates "even" distortion? Is this not possible, or is it cost-prohibitive?

[sfogg]

Dean,

"...and the lower the output impedance of a tube amp the more like solid state it sounds. At least, that's what I think."

Yup, unless of course the SS amp has a fairly high output impedance. I measured the Monarchy SM70s output impedance at around 3/4 of an ohm for example. Sunfire amps have an output on them which has about 1ohm of output impedance.

The flip side is with a non-reactive speaker load the differences from amps with different output impedances changes too. I think it was in Stereo Review back in the late 80s or early 90s but E. Brad Meyer did some double blind ABX testing between SS and tube amps with different speakers. On some speakers (benign impedance) the listeners could not tell the amps apart when they were level matched and double blind. On other speakers (much more reactive) the listeners could easily tell the same two amps apart.

"I just need to find a low powered SS powered amp with 6dB of headroom (and then be able to pay for it:). I ran NAD in the early 80's"

As you surely know NADs are well know for their dynamic headroom. Adcom's are typically listed at around 2-3dB of headroom (if I'm remember it correctly) and many other SS amps had similiar ratings.

Shawn

[NOSValves]

"Were not talking about measured power were talking about perceived power playing music."

Well, that's SPL in db's not watts!

Watts are electrical - Just trying to help you out here, bub.[]

DM

BUB! Now that is a cute name []

No help needed.. Peak instantaneous watt abilities is what I'm talking about. To tell you the truth I have no idea how it can be measured. It would take some test equipment that reacts seriously fast which I can not afford. While you keep bringing up steady state rating into a dummy load running a single sign wave. That ain;t music BUB[]

By the way saying someone is stating a "CROCK" is usually not considered helping them out.

Craig

[sfogg]

" It seems the consensus is that the distortion created by tubes is of a different (even) order than the distortion created by SS (odd). "

No, that isn't the consensus at all. Go look at actual measurements of various amps and their distortion spectra and you will see even in SS and odd in tubes.... and vice versa. Again, depends upon the design of the amp. Not if it is tube or SS. I posted a bunch of measurements I did of different amps in the old forum but I think they are basically gone now.

"Or is this topic beyond any meaningful scientific analysis?"

No, having any meaningful discussion analysis is just far beyond any sort of gross generalizations such as tubes = even, ss = odd.

"come about by introduction of 300 wpc tube amps that have huge damping factors?"

Power has nothing to do with damping factor. You could build a 1w amp with a high damping factor. Or you could build a 300 wpc amp with a low damping factor. Damping factor is simple the relationship between output impedance and the load you are driving.

Shawn

[Jeff Matthews]

"Were not talking about measured power were talking about perceived power playing music."

Well, that's SPL in db's not watts!

Watts are electrical - Just trying to help you out here, bub.[]

DM

BUB! Now that is a cute name []

No help needed.. Peak instantaneous watt abilities is what I'm talking about. To tell you the truth I have no idea how it can be measured. It would take some test equipment that reacts seriously fast which I can not afford. While you keep bringing up steady state rating into a dummy load running a single sign wave. That ain;t music BUB[]

By the way saying someone is stating a "CROCK" is usually not considered helping them out.

Craig

I think he is just using a lively tone for his argument and does not mean to offend. But anyway, talk to me about what you mean regarding a difference in "peak instantaneous watt abilities." Is this something that varies when clipping begins. Or is it ever present in the music, even at more moderate volumes?

[NOSValves]

Actually... what you said was...

'So a quality 20 watt AB Push Pull amp has the ability to operate similar to a 40 watt class A tube amp or SS amplifier "

Which is nonsense.

A quality 40 watt SS amp is going to still have dynamic headroom above its steady state rating. So your quality 20w continuous tube amp... even if it has 'double' the dynamic headroom at best is going to be able to peak out at what the SS amp is rated for continuous power. That SS amp will have dynamic headroom beyond that point. If it has 3dB of headroom (a typical amount for SS) that means 80w.

And then throw in a reactive speaker where the quality SS amp will *double* is power output with the halving of impedance (and the tube amp will at best have the same power... but with higher distortion) and we can really see what happens.

Shawn

Put your money where your Spec is. Take my challenge. I guarantee you a 20 watt SS amp will drive people out of the room before a 20 watt tube amplifier SPL wise. We can spout specs all we want but in the end never answer the mystery completely. SPECS are not the absolute end all. I still have never experienced an SS amp that shows any sign of USEABLE headroom above its rated steady state output playing music. The same is true with Class A tube circuits IMHO. If you put all above mentioned on a steady load and pump sine waves into them and you get no explanation as to why it is BUT IT IS. Why do you think Klipsch started recommending using amps with 5 times the power then you think you will need? This was not the case before SS came along.

Craig

[Jeff Matthews]

"So, now that that is out of the way, a more intelligent discussion of tubes vs. SS can take place. It seems the consensus is that the distortion created by tubes is of a different (even) order than the distortion created by SS (odd). I noticed on the specs NosValves posted of the MK amps that the distortion percentages are substantially higher than the specs usually found in SS. I think it was along the order of 1% distortion in the tubes, whereas, we often see something like .05% in SS. So, is there any science that compares 1% "tube" distortion to .05% SS distortion? Or is this topic beyond any meaningful scientific analysis?" ========= Good lord, it's 1972 all over again. Mine has 0.001%THD and 120W, therefore it must be better than yours with 0.1%THD and 50W. The Pioneer SX-1080 simply the only amplifier will ever need. And hey-it's in a receiver with a boatload of knobs too? Oh, I know, let's buy amplifiers by the pound! Or, how about by the size of the heatsink? Output tubes? No wait, mine has a bigger transfomer! Mine has bigger caps - a hefty 50,000uF - it "must" have great bass, huh? You have a thing called ears. They can be a very useful judge of amplifier sound quality. Try it sometime, you might just amaze yourself! Listen critically to a variety of amplifier designs, and eventually you'll reach the only meaningful consensus - yours. md

Per MD, sounds like the topic is beyond any meaningful scientific analysis.

[sfogg]

Craig,

"I have no idea how it can be measured. It would take some test equipment that reacts seriously fast which I can not afford."

How it is measured varies... which is also where some of the problem is. Not everyone uses the same method of measuring it. Some measurements are literally at less then a ms of 'peak' power. That is useless 'marketing' power as for a lot of the spectrum that can't sustain the peak power level for even one cycle of a wave.

Continuous power ratings are far more useable information then peak ratings because of that. An amp with 20w continuous and 40w peak is not the same thing as an amp with 40w continuous. The 40w continuous amp can sustain 3dB higher SPLs then the 20w amp.

Shawn

[NOSValves]

"Were not talking about measured power were talking about perceived power playing music."

Well, that's SPL in db's not watts!

Watts are electrical - Just trying to help you out here, bub.[]

DM

BUB! Now that is a cute name []

No help needed.. Peak instantaneous watt abilities is what I'm talking about. To tell you the truth I have no idea how it can be measured. It would take some test equipment that reacts seriously fast which I can not afford. While you keep bringing up steady state rating into a dummy load running a single sign wave. That ain;t music BUB[]

By the way saying someone is stating a "CROCK" is usually not considered helping them out.

Craig

I think he is just using a lively tone for his argument and does not mean to offend. But anyway, talk to me about what you mean regarding a difference in "peak instantaneous watt abilities." Is this something that varies when clipping begins. Or is it ever present in the music, even at more moderate volumes?

And I'm just replying in a like manor!!

Peak instantaneous watt abilities = It's the ability for an amp to reach beyond its "Steady State wattage" for very brief transients. I personally think tube amps especially quality PP AB do this better then most any other amp. Obviously Shawn does not. But that's not surprising some engineer types have trouble believing anything they can not see on there test equipment. I'm sure with enough available cash and technical no how a power test setup could measured this to some degree. I just know its way beyond my wallet. The big boys in the business most have a way since they rate amps in this fashion. Although it wouldn't surprise me if they use some mathematical equation to come to a educated guess.

Craig