[MaxCast]

Hevia....are their copies floating around.  I sure would like to hear this CD.  If anyone has a way to burn please LMK.

[Ravi]

No one can question their technically more accurate response as compared to tubes

I can. What it boils down to is that the "accurate" response that gets trotted out in statements like this are not what is relevant with respect to what our ears hear. Hey, why don't *I* say it for a change, check Dan Banquer's FAQ

JohnR

Thats why I said "technically", and not subjectively.  I'm not talking about what our ears hear.  I'm talking about how they measure on a graph.

[JohnR]

Thats why I said "technically", and not subjectively.  I'm not talking about what our ears hear.  I'm talking about how they measure on a graph.

OK, let's talk technical then

Which amplifier is technically superior: one that has 0.1% THD, but it's all second harmonic, or one that has 0.001% THD, where the harmonics are even in amplitude all the way up to the 50th harmonic?

JohnR

[audiojerry]

Ravi,
I must be misunderstanding your point:

Here is my 2 cents. If all recordings were perfect quality, then SS would be the best. No one can question their technically more accurate response as compared to tubes. They have alarmingly low distortion, and can render the high frequency ranges with less distortion than most tube amps. Tube amps generally start to have rising distortion anywhere from 1 to 15khz.

It seems to me that you are stating that solid state will sound better than tubes if the recording were perfect because ss is technically superior - just check the measurements.

I believe John is trying to point out that there are no measurements that are able to evaluate or 'measure' the way something sounds as well as the human ear.

I might be wrong by this example that I ofen use, but can any test equipment in existence today be able to quantify the differences between a Stradovarius and a $300 Stentor? Certainly to almost everyone's ear, the Strado will sound far superior, but is any electronic measurement device able to come to this conclusion?      

Tube gear measures badly, so why does it so often sound much better than transistors that measure superbly? Even within the realm of SS amps. I'll bet there have been countless reviews of very expensive, well built amplifiers that have had impeccable measurements, but nearly everyone hated the way it sounds.  

I don't think either side can use measurements to support their preference for one over the other.

[DVV]

Hevia....are their copies floating around.  I sure would like to hear this CD.  If anyone has a way to burn please LMK.

Pst, Max? Jerry has a copy ...

Cheers,
DVV

[Dan Banquer]

Well Jerry I think we can measure a lot. We can measure the harmonics in the frequency domain and time domain, which will tell us a lot about the "tonal signature" of the two violins in question. I think the real measure here is whose hands is the violin placed in.

[DVV]

Well Jerry I think we can measure a lot. We can measure the harmonics in the frequency domain and time domain, which will tell us a lot about the "tonal signature" of the two violins in question. I think the real measure here is whose hands is the violin placed in.

I tend to agree with Dan, though I'm perhaps a little more cautious.

Measurements are an invaluable tool in the hands of every and any designer, assuming he knows how to make them and much more to the point, how to evaluate them. Much like specifications.

While I will agree with Jerry that measurements cannot fully express how something sounds, I must point out they can give one a reasonably fair idea of what to expect from some unit. They sort of tend to show the probability of how it sounds on an overall basis, even if that's not the current "in" view.

For example, tubes usually exhibit even order harmonic distortion, so seeing that on a 'scope will USUALLY mean a sweet and mellow sound. But not necessarily also an accurate sound.

By the same token, an SS amp may show odd order harmonic distortion artefacts, implying harsh and brittle sound, yet still actually sound rather good.

The problem here, Jerry, is that we are talking about parts of the whole, whereas it's the whole which accounts for the sound. In other words, a well designed amp will have ALL forms of distortion equally present, so when you apply negative feedback, all forms of distortion will be equally surpressed. Just one form of distortion out of proportion and you don't have an accurate amp, although it may sound very seducing.

After all, a wicked woman may seduce you, and you may succumb to her charms, but that won't speak much of your marital fidelity, will it?

Get a load of THAT comparison!

Cheers,
DVV

[Dan Banquer]

I still am convinced of the following. People use tubes to mask the distortion of poorly designed and poorly implemented tweeters, along with poor room acoustic treatment. I consider this to be the real core of the problems that folks like jerry experience.

[Brad]

I still am convinced of the following. People use tubes to mask the distortion of poorly designed and poorly implemented tweeters, along with poor room acoustic treatment. I consider this to be the real core of the problems that folks like jerry experience.

Gosh darn them for deriving musical satisfaction from their systems.
That should be stopped at all costs!!!

[JohnR]

I believe John is trying to point out that there are no measurements that are able to evaluate or 'measure' the way something sounds as well as the human ear.

Partly, but also, when someone says "technically more accurate," you have to ask by what measure. The example I gave was purely technical. Which of the two is superior?

Now add a few more axes. Distortion against power output. Against fundamental frequency. We're still only doing static sine waves, note. Now add a second sinewave (adventurous!) Now use bursts instead of static tones. Now use reactive loads.

So now we have at least seven axes of measurement. How would one decide which of two sets of measurements was "technically more accurate." Well, that would be tough, because you have one specimen that looks better in some places, and one that looks better in other places. LIke the example I just gave. You would have to come up with a heuristic of some sort for weighting all the measurements to produce one or perhaps a few indicators of "technical accuracy."

Aha. But what measure would you use to evaluate the quality of your heuristic? Hm... good question.... I know! How about evaluating it against subjective sound quality?! Now there's a novel idea. Radical. Maybe I can patent it. Wouldn't that be interesting. Correlate measured data against observation.

My hat goes off to the gentleman in this field who attempt to do just that, despite the ridicule from both sides of the "measurement/subjective" divide.

JohnR

[MaxCast]

I still am convinced of the following. People use tubes to mask the distortion of poorly designed and poorly implemented tweeters, along with poor room acoustic treatment. I consider this to be the real core of the problems that folks like jerry experience.

I think AJ said he thinks his room is too quiet/dead.  I also think AJ just likes the sound of tubes, period.  

I use a pair of Le amps and also have a pair of cheap Wave-8's.  I can see and hear the provocativeness of tuuubes.  I switch between them at will depending on my mood, so there!    I would love to try a pair of Dan's amps but they are a bit out of my reach.  I certianly appreciate those participating in this thread and the amp thread.  I wish the other amp manufacturers would join in the discussion too.

Hey, AJ, any chance on getting a copy of the Hevia disc?

[audiojerry]

Pst, Max? Jerry has a copy ...

Sorry, but I passed the copy along with the Dezorel!
I'm still surprised that none of the reviewers has commented on the Hevia music.

After all, a wicked woman may seduce you, and you may succumb to her charms, but that won't speak much of your marital fidelity, will it?  

My wife IS the wicked woman!

[Dan Banquer]

Very good John; now we are getting to the root of the problem. Distortion, harmonic and IM measurements need to be done at different output levels and different load levels. This is rarely done. I had a good portion of this done with a friend of mine who had an Audio Precision One at his disposal. Believe it or not  sine waves are still pretty useful. BTW when was the last time you saw any magazine do these measurements in this kind of detail?
Another word about tweeters and that "solid state harshness". For many years I had a speaker with a focal inverted hard dome tweeter. As I developed my audio electronics I brought the "harshness" down as low as I could, but still had some residuals there that I couldn't get rid of. Mike McCall had loaned me a set of his Eires, and that residual harshness dissappeared. The rebuilt Fried's that I have now that use a hiquophon tweeter, don't have that residual harshness either. For a long time I was suspicious of the focal hardome, because nothing in my distortion measurements indicated I had any distortion to cause what I heard out of that focal hardome. I rest my case; for the time being.

[DVV]

Pst, Max? Jerry has a copy ...

Sorry, but I passed the copy along with the Dezorel!
I'm still surprised that none of the reviewers has commented on the Hevia music.

You said it, Jerry. I feel somewhat let down myself.

After all, a wicked woman may seduce you, and you may succumb to her charms, but that won't speak much of your marital fidelity, will it?  

My wife IS the wicked woman!

How convenient.

Cheers,
DVV

[JohnR]

Oh, I forgot that you would want to vary the magnitude of the load as well as the phase angle

I don't know what an Audio Precision One is but I expect it's expensive. I'm just wondering whether it would be possible to automate a lot of this. Say one got hold of a high quality A/D/A with a USB interface, it seems like you could do quite a lot with a little software. You'd need relays for switching the load, but other than that it's "just programming." Dan, is this kind of thing feasible these days?

JohnR

[DVV]

...
Another word about tweeters and that "solid state harshness". For many years I had a speaker with a focal inverted hard dome tweeter. As I developed my audio electronics I brought the "harshness" down as low as I could, but still had some residuals there that I couldn't get rid of. Mike McCall had loaned me a set of his Eires, and that residual harshness dissappeared. The rebuilt Fried's that I have now that use a hiquophon tweeter, don't have that residual harshness either. For a long time I was suspicious of the focal hardome, because nothing in my distortion measurements indicated I had any distortion to cause what I heard out of that focal hardome. I rest my case; for the time being.

Remember Dan, if you want the harshness gone, use composite caps (polypropylene in parallel with polycarbonate) and pure silver braided wiring for the tweeter and most will come on song. Especially titanium domes. Most especially JMLab/Focal inverter titanium dome tweeters, belive me, it's been tried locally often enough. Caps by Wima.

Cheers,
DVV

[Ravi]

I must say, this is one of the most interesting threads on audio I've ever read.  

John, yes, you're right, you must weigh all the options such as load and output levels when measuring amps.

Let me explain why I got the impressions that some Tube amps have a lot more THD than equivalent priced SS amps.  Let me use the Jolida 302B integrated EL34 amp as an example: Distortion THD: Less than 1% at 50 W output, 28Hz to 15KHz .  Notice how at rated power, they only rate up to 15Khz, and only down to 28hz, beyond those points, THD rises above 1%.  Then compare that to a Denon DRA-685 stereo receiver that lists a THD of 20hz to 20khz at 0.5% THD at full power.  Now whether they took into account all the important criterias , probably not.  Most would prefer the Jolida when doing an A/B listening test.  Now a manufacturer may look at these numbers and think its utter B.S.  Just calling them like I see them, even if from a flawed viewpoint.

Jerry, as Dan Banquer mentioned, my belief is also that people use tubes to mask other deficiencies.  Now Dan has a lot more to back that up than I do, all I can say is thats what I've gathered from my brief experience.  In a lot of instances, with Jazz and such, I do prefer tubes, but for other types, SS has better attack and rhythym, and much more detail in the bottom 2 octaves.

Again, this is IMHO, I don't know as much about this as most of you, but this thread is a great way to learn!

[Marbles]

After all, a wicked woman may seduce you, and you may succumb to her charms, but that won't speak much of your marital fidelity, will it?

Cheers,
DVV

Who is this woman and where does she live!!??

[audioengr]

Jerry wrote:

Tube gear measures badly, so why does it so often sound much better than transistors that measure superbly? Even within the realm of SS amps. I'll bet there have been countless reviews of very expensive, well built amplifiers that have had impeccable measurements, but nearly everyone hated the way it sounds.

Well, I thought I would weigh-in since this is such an interesting thread.  My theory has to do with dielectrics.  In SS amps, the whole signal path is on PC boards that have FR4 dielectrics (Er = ~4.7).  They also historically have used  poor capacitor choices for series caps. Lots of dielectric absorption here.  These are the kinds of differences that can make things sound harsh and sibilant even if they measure well.

Tube circuits on the other hand are largely wired point-to-point with decent wire, sometimes with thin Teflon insulation.  Lots of air dielectric.  They also tend to be more picky about caps in the signal path.  The wire itself can also be higher quality (crystal-lattice) than copper on PC boards.  My 2 cents.

[DVV]

After all, a wicked woman may seduce you, and you may succumb to her charms, but that won't speak much of your marital fidelity, will it?

Cheers,
DVV

Who is this woman and where does she live!!??

Jeez Marbles, you're getting old - what took you so long?

Cheers,
DVV