John Curl's Blowtorch preamplifier part II

[stinius]

Holy cow, Chris! I'm supposed to READ all that????

Sy I have read the whole post by Chris, and guess what, I agree.

Hi Joshua,
I think you are missing the forest for the trees. Focusing on one issue hides it's relationship with the entire "production". This is also a common problem with some designers, where they focus on one aspect of performance to the detriment of all other aspects.

Remember. The 7th harmonic is accompanied by many others, then add IM distortion and perhaps some cutting edge worries. Every issue has a threshold where it becomes a concern. So until the other issues are dealt with, worry less about the 7th.

As a note, I tend to look at the spectrum up to the 10th harmonic. The 7th is no more special or threatening than the 8th or 6th or any others. Because of it's lower frequency, I'll wager that 5th and 6th are more important than 8th or 9th. Notice how I avoided the 7th? I don't want it stuck to the bottom of my shoes.

-Chris

Chris I agree on this one as well.

Cheers

 

[john curl]

People here are clueless about 7th harmonic and its effect when added to musical reproduction. Also, your heads are in the sand. What must I do to get you to read up on the effect of 7th harmonic in regards to the musical scale? We normally listen to music, don't we? That is where 7th harmonic becomes so important.
If we were banging pans together in some sort of of order, in order to make another special kind of 'music', the added 7th harmonic, might be useful.

 

[Joshua_G]

Please tell me what you read between the lines of this review.

I wouldn't bother, I have better things to do than analyze any review.

BTW, do you hold that Stereophile reviews are the absolute truth?

 

[SY]

No, quite the opposite. But many here, including John, tout "good reviews" as validation of their designs.

 

[Joshua_G]

Hi Joshua,
I think you are missing the forest for the trees. Focusing on one issue hides it's relationship with the entire "production". This is also a common problem with some designers, where they focus on one aspect of performance to the detriment of all other aspects.

Remember. The 7th harmonic is accompanied by many others, then add IM distortion and perhaps some cutting edge worries. Every issue has a threshold where it becomes a concern. So until the other issues are dealt with, worry less about the 7th.

As a note, I tend to look at the spectrum up to the 10th harmonic. The 7th is no more special or threatening than the 8th or 6th or any others. Because of it's lower frequency, I'll wager that 5th and 6th are more important than 8th or 9th. Notice how I avoided the 7th? I don't want it stuck to the bottom of my shoes.

-Chris

I agree that there are other issues of crucial importance, like IM and TIM, or its' derivates, however, the 7th harmonics has unique importance, more than the 8th, 9th and 10th. This is for psycho acoustics reasons.

 

[Joshua_G]

No, quite the opposite. But many here, including John, tout "good reviews" as validation of their designs.

If you don't have high opinion on Stereophile reviews, why bring it up as a reference? It looks to me like an argument for the sake of argument on your part.

 

[john curl]

Joshua, you must be more careful what you write here. You made a serious error in stating that 7th harmonic doesn't occur in nature. The true fact is that 7th harmonic is not related to the tuning scales that we use for western music. This IS important, and should be understood by everyone. The fact that most contributing here appear clueless to this fact, doesn't stop them from criticizing you, because you were not careful enough in your original statement.
Of course, you are correct that 7th harmonic and its related IM products that are produced by the same nonlinearity that originally created the 7th harmonic in the transfer function are very audible, and every effort must be made to reduce it to reasonably low values.

 

[anatech]

Hi Joshua,

... is that measurements alone aren't enough to tell how an amp will sound, at least not published measurements.

That's fair enough. I can tell you that designs done by ear alone have a tendency to go off in poor directions too. Both listening tests and measurements are required to create a well designed amplifier.

I agree that there are other issues of crucial importance, like IM and TIM, or its' derivates, however, the 7th harmonics has unique importance, more than the 8th, 9th and 10th. This is for psycho acoustics reasons.

That may well be Joshua, but you may well be talking about something you can't sense anyway. Besides, any design directions you take that will reduce the 7th harmonic will also reduce all other high order harmonics (save using DSP technology to notch it out! ). Therefore, treating the base problem of high order harmonics will also treat the 7th. So, in view of this revelation, why specify the 7th when you can't do anything without affecting the other problem harmonics. It makes no sense what-so-ever to look at this and ignore the surrounding harmonics.

What am I missing here? Anyone? John?

Hey stinius,
You read all the post? I'm really sorry about that. You should go get yourself checked out now!

-Chris

 

[SY]

John, look at the 1W spectra. They're awful. You wouldn't accept that and neither would I.

 

[john curl]

You are right SY, I stand corrected, in this case.

 

[Joshua_G]

Joshua, you must be more careful what you write here. You made a serious error in stating that 7th harmonic doesn't occur in nature. The true fact is that 7th harmonic is not related to the tuning scales that we use for western music. This IS important, and should be understood by everyone. The fact that most contributing here appear clueless to this fact, doesn't stop them from criticizing you, because you were not careful enough in your original statement.
Of course, you are correct that 7th harmonic and its related IM products that are produced by the same nonlinearity that originally created the 7th harmonic in the transfer function are very audible, and every effort must be made to reduce it to reasonably low values.

Thank you, John.
You are right, of course, I didn't phrase it properly.

 

[Joshua_G]

That may well be Joshua, but you may well be talking about something you can't sense anyway. Besides, any design directions you take that will reduce the 7th harmonic will also reduce all other high order harmonics (save using DSP technology to notch it out! ). Therefore, treating the base problem of high order harmonics will also treat the 7th. So, in view of this revelation, why specify the 7th when you can't do anything without affecting the other problem harmonics. It makes no sense what-so-ever to look at this and ignore the surrounding harmonics.

The 7th harmonics distortion is the most objectionable one to the ear. When by reducing the 7th harmonics distortion higher harmonics are also being reduced, which is being done quite naturally, or automatically – that's an extra benefit.

 

[anatech]

Hi John,

This IS important, and should be understood by everyone.

It's understood, but I still like the sound of chimes. Even bought a set in D minor (they are large).

The fact that most contributing here appear clueless to this fact, doesn't stop them from criticizing you, because you were not careful enough in your original statement.

That wasn't a very nice thing to say John. For one, it's an assumption, and for two, it had nothing to do with what was going on with Joshua. You may be too close to the topic of 7th harmonic distortion as you're point of view seems to exclude other reasons for the posting here. You're fixated it seems.

Now, a question. Assuming we know about the "7th harmonic problem", but we are also aware that we can't do anything about it in isolation, should we exclude affecting all other high order harmonics in our attempts to create a better sounding system? I don't know about you, but I'm not about to start to worry about anything I can't change. I will take opportunities to improve everything though, and if it reduces the level of the 7th harmonic, so be it.

It is just that he is trying to get your 'goat' and mine, by putting it up.

Now, there is an assumption that is unnecessarily upsetting to you. Why not assume a lack of malice in people rather than seeing it behind every tree? You'd be a happier guy for it.

Most people I find do not mean other people harm. Those that do are generally called "Trolls" and they bother many people, not just one.

Best, Chris

 

[john curl]

Anatech, please, you too can read up about 7th harmonic on Google. Really, this is important, if you want to understand what we are talking about. For example sixth harmonic is OK, 8th harmonic is great! Why do I pick on 7th harmonic?

 

[stinius]

John

I think that you are mixing a few things here. Namely the 7th harmonic distortion in an amp and the 7th harmonic overtone in a piano, related to the tuning of the piano.

Cheers

 

[GK]

Have any of you clowns still stuck one rung up from the Edison drum ever heard of a CD player?

 

[Bas Horneman]

Have any of you clowns still stuck one rung up from the Edison drum ever heard of a CD player?

A what?

 

[Curly Woods]

Have any of you clowns still stuck one rung up from the Edison drum ever heard of a CD player?

Yes indeed. I own one to listen to background music during parties and when I am busy.

 

[john curl]

Well, everyone, you can learn from an experienced expert, or you can live in ignorance. It is your choice, not mine.
Now where do I get my input? How about stuff from 70 years ago? They knew about 7th harmonic in reference to amplifier distortion. Where do you get your input? From solid deduction, based on your engineering training?

 

[jacco vermeulen]

Have any of you clowns still stuck one rung up from the Edison drum ever heard of a CD player?

Someone sure has to without a phono input.
But what lovely cornering.