John Curl's Blowtorch preamplifier part III

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Richard, once upon a time I was seriously going to build that unit...and then got a job working with a sound contractor and had access to an HP/Altec 8050A...thank you for having sparked my imagination with that article!! I remember it well. I do have one qualm about your construction, however: WHY A FAUX WOODGRAIN FRONT PANEL?!?!?!?! lolol

Cheers,
Howie

🙂

The tech built that for himself and for the magazine photo-op. Mine is in an unpainted aluminum rack mount chassis with handles. Still have it stored. Just saw it today looking for other things.

It was cheap to make... the way i did it, anyway. A good historical look at EQ is here:

Handbook for Sound Engineers - Google Books

Now I have such things in my pocket iTouch etc Including high rez filtering/display and FFT and every imaginable measurement you can think of.... small and battery powered.

But it still comes down to my bottom line about listening near-field for accuracy to the source.


-RM
 
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The final authority on any audio related component are human ears and what they hear.
...
Let's put them in a completely unknown environment and DBT them to death.

So is the final authority before or after lunch?

(This is repeatable, see how fallible we are?)

Justice is served, but more so after lunch: how food-breaks sway the decisions of judges - Not Exactly Rocket Science : Not Exactly Rocket Science

That said, one's own preferences are whatever they want. No need to justify them, but be careful with easily falsifiable claims. 😉
 
Anatech, you again force me to defend B again!
SY could have seriously tested the Bybee device, but he didn't. He should have taken it apart, analyzed it, and then decided if he could duplicate it with a simple resistor, BUT HE DIDN'T. He just made some resistance and impedance measurements, and called it a day. If he had taken it apart, he would have found it far more subtle that he would have expected, and with an electron microscope, he could have found out what it was made of, BUT HE DIDN'T. Now, over the years I invited SY to meet Jack Bybee and also showed him one that was taken apart. I can't do any better than that, but he ignored everything that I offered.
SY even decided that I must be some sort of 'liar' for sticking up for Jack B. and he tried to prove this by 'catching me out' in comments that I made online.
One example, was my ownership of Feynmans 'Lectures on Physics,#3' that I acquired in 1966. I bought this book in order to attend the course on Quantum Mechanics while finishing my senior year in college. However, after a few weeks into the class, I was forced to drop out, because I could not maintain the course load, and work part-time at the same time. I hated to drop this class, but it was an elective and I could graduate without it. It was my only real choice. Well, SY took my input here as claiming to have taken a course in QM, when he knew that I did not have the background to complete the course, so he called me a 'liar'! Well, I did NOT complete the course, in fact I had just started it, but I did keep the book, and I now have all the Vols 1-3 on my bookshelf. Why had SY not given me the benefit of the doubt, and then asked me to clarify myself? No, he would rather impugn my reputation. It is not a good thing.
SY also accused me of being in a secret partnership with Jack B., and I must admit that Jack sort of advertised it that way, but it wasn't true. I just did small, (non QM) projects for Jack that he incorporated into some of his larger AC conditioners, where he gave me a small royalty for my part (simple lightning and RFI protection) of $5/unit. I made a few hundred dollars over the years, but I certainly was not a business partner. Tell that to SY sometime when you talk to him. It always hurt to be called a liar by someone like SY, and not be able to defend myself adequately at the time. You can tell him for me.
 
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You are misinterpreting the equation. Qes is not some existing damping factor which the amplifier then degrades, but the electrical damping which comes from the speaker plus amplifier plus cable. Hence it is quite meaningless to talk of "eroding" Qes, or the ampliifer only making things worse; in the absence of an amplifier there is no electrical damping and Qes is infinite - it might be closer to the truth to say that the amplifier can only make things better! Qes is what it is; it is minimised (i.e. maximum electrical damping) by minimising total resistance. In most cases an approach to voltage source is a practical minimum, but negative output impedance could push it down further provided that stability can be maintained. Qes is maximised by omitting the amplifier, or by using current drive.


You must be reading a different thread.

It is clear that you are misinterpreting me. You have built all that stuff up based on what you believe what I believe? Sorry, that is way off the mark.

Oh, no damping when the amplifier is not connected? Well, the Re has become infinite, so no electrical damping. But it seems to me you want to just pick an argument with me. Well, that won't work.
 
For discussion's sake, here's a little twist... Why are you guys so against the so called bias? Isn't bias a part of being human? Our entire existence and every decision we make in life is influenced by bias. Let's take an example:

Let's say person A went amplifier shopping and picked a $300 amp which he/she was able to consistently pick out as the best sounding one in a DBT.

Person B spent $300 on an oil filled silver capacitor, which due to the so called human bias, made a similar improvement as did the amplifier to person A.

Which person made the better purchase and why?
 
Hi John,
I will do my best to remember to let SY know the next time I talk to him. But you should know, he didn't do any destructive testing as it belonged to Cal. He promised not to do it any harm, although I'm sure he was burning to take it apart.

As far as claims made for that item, it only has to show an effect just beyond the audible range, so up to 100 KHz would be more than adequate. If there is no way to coax some kind of effect from it within that range, it simply could not have any bearing on what you can hear. Regardless of it's supposed quantum properties, no matter what they are. Now, if there was some way to test it, Mr. Bybee would have that procedure known within the assembly area for QC purposes if nothing else. If we were to give a nod to 1970's marketing, there would be a nifty display that would have one of these things that could be tested in and out of some kind of circuit as a sales aid. Especially when the claims are so tenous. So, for many reasons, I'm not buying it as something that can make any difference, good or bad, other than what that resistor value is. Besides, SY gave me his word on what he found and I'm not so stupid as to disbelieve him. I know the man's methods and have seen several experiments he has been conducting on even things that have nothing to do with electronics. He has the method down and only allows one variable to be at play. So aside from what you say he called you, I would be looking to prove these devices experimentally on your own. Not with listening tests. If you can hear it, you can measure it for sure. You should know how to do this from your long experience with audio products. Better late than never to assure yourself John.

-Chris
 
There are many very bright members here and you have to give them their due.

Best, Chris

Sure, but maybe if some of them were a little less combative, that would make for a better spirit.

Re bright people, in recent years the discussion we are having on loudspeakers has taken a certain tack, but like the Titanic, some things are hard to turn. When it comes to understanding what speakers does, there is still a lot of fog out there. Now some will say here that I am imaging this, that there is no fog - but the truth is that people's understanding is all over the place and that there is a lack of framework - so we get others saying 'black art' and stuff like that. That too is not a satisfying situation either. But I know several physicists are now looking at this - and when the time is right, maybe we can have a respectful conversation about it.

It seems that current is the key (and NOT current drive, which is a different topic and in my mind NOT the solution) - and that the amplifier should be able to produce both voltage and current squarewaves into the load - and when you do, something rather interesting occurs, the source impedance of the amplifier becomes mute and the load must be purely resistive. Hans van Maanen in the Netherlands is down that road (Temporal Coherence - Natuurlijk geluid dat je raakt... - Home) and yes, he is a physicist.

I am just saying it - no need to go after my head now, right? I believe this is an interesting topic and wish others were also interested.

Cheers, Joe

PS: What I have said so far was only because of the quote below caught my eye and I believe there is some truth in that - great speakers are very rare.

A great many strong opinions around here show a degree of innocence or inexperience with making really good audio designs that can be misleading. It is very difficult to make really good audio electronics, and almost impossible to design really great loudspeakers. I still think that the challenge is there, big time, with loudspeakers still.
 
Hi ridikas,
Simple. The person with the $300 amplifier.

It can be insured without undue scrutiny. (and he has stereo)

-Chris

I disagree. If both made a similarly priced purchased and heard a similar improvement, then what's the difference? If the brain is tricked to the point of not being able to differentiate bias from no bias, then all is good for both shoppers.

Isn't the actual act of doing a DBT a human bias?
 
Hi Joe,
But in context in this thread, we are talking about the electronics primarily. There are some things that are not possible, and we have all learned how the laws of physics work concerning things like amplifiers and electrons in wire. When a viewpoint is expressed strongly by a person or a small minority that differs from what is actually possible, they had better have proof that can be replicated and documented. If you are about to defend yourself by saying something along the lines of "well, it could happen, you don't know it couldn't", you have done a number of things wrong.
1.) The theory was presented before any study was done on prior findings.
2.) The presenter hasn't the education required to prepare an argument needed.
3.) The argument has just wasted everyone else's time.
4.) Depending on how the argument was presented, everyone else's intelligence has been insulted.

I do keep an open mind on anything that doesn't require known facts to be suspended. These known facts are things that we learned and had demonstrated to us either in school / university or some kind of formal education, or by direct experimentation that can be replicated by others. I would never consider introducing an idea that would challenge what is known about anything scientific unless other people were able to replicate my results successfully. Doing so would be pure folly, and pretty stupid given how I would expect others to react.

The reactions around here are stronger because these ideas have been introduced, then continually trotted out whenever it seems convenient to do so by a few individuals. I am surprised that people who do this do not seem to learn from past experience.

-Chris
 
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