John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
Is that your take on the HP 4328A Milliohmeter? It used AC excitation (for a whole lot of good reasons) and measured only the resistive vector.

Verifying over a frequency range is really difficult. I found that at milliOhms the inductance of a short wire can be significant. What you may be seeing is the inductance of the series impedance affecting the reading. i know low inductance milliOhm resistors are not common. In fact they are really hard to make. I believe JNeutron showed one way and that would be a good starting point for checking the test system.

I was given a copy of a manual for a Siemens contact tester that looked for momentary variations on contact resistance. I was interested but the instrument was far too involved to hatch a copy. Essentially it applied an HF signal across the contacts and any variation in the amplitude was recorded.

Demian,

No it is that I am building a new set of test equipment modules and learning a bit in the process.

So far a low noise amplifier, a quadrature oscillator, a vector amplifier and a twin T notch filter. Still need to assemble the precision attenuator.

Up for revision already is the low noise amplifier and the oscillator. Turns out not only is quadrature useful but so are the first few harmonics both ways.

From this gear I should be able to do a few more interesting test setups. As a Fourier transform analyzer is the basis of almost all tests it will be interesting to look elsewhere.

ES
 

Attachments

  • Z new test equipment.jpg
    Z new test equipment.jpg
    530.7 KB · Views: 182
I think most of us, but sadly not all of us, would agree that circuit theory cannot be violated. Many of us would also want to see Fourier and Shannon sampling theory taken more seriously. More consistent applications of Occam's Razor would help too.

Circuit theory is a theory that tries to model the behavior of circuits. It has limits and does not describe all of the effects. For example skin effect does not come out of circuit theory. Then there are programs such as spice and the variants that use piece-wise approximations.
 
If that includes scalar wave and Schumann resonance generators, I disagree. The second law and Shannon are not sacred cows they're facts.

I don't know why you have it in so for Schumann gizmos.

Schumann Resonance Devices for Electro-Magnetic Safety

I like to have a good bit of humor every day.

Now when they discover a motorized moving magnet is the right way to generated a cost effective high power undulating field at a minimum cost everyone can have them. I bet offshore they can be made for under $1!
 
  • Like
Reactions: 1 user
Since you're attributing a bunch of things to me that I never said, I can't really respond to them.

But if you want to know what your distortion threshold is, you can use some software tools to determine this. It truly is not difficult.

The problem is..... that the problem itself is not well defined enough to be aided in it's definition via the use of hardware, 'hardware in context' as the sole definition of the range/parameters/field of the issue.

This is seen to abundantly true by a person who uses observation as the defining aspect of how to approach a problem or conceptual issue.

Observation has to remain as the peak decider or arbiter in all complex and undefined scientific endeavor, otherwise the arguments go circular and dogmatic, trapped in ritual and incompleteness.

Depending on the given intellect at hand in the given problem set, the problem can be evident, or seemingly solved, or a nebulous non existent confusion. This is due to individual limits in scope of mind ---being individual in neural wiring....not universal.

Further, powerfully confounding the integration issue...comes the condition of engineers trained as factual exemplars, and contrarily...scientists properly trained as explorers.

In exploration, facts do not exist..only theory...theory which is subject to change.

Therefore, in any discussion of extant problems that remain unresolved, all facts have to retreat back to their actual conditions, which is that of theory, theory which is subject to change - depending on the observation of evidence and data.

If this was not the reality, then no problem of any kind would ever be seen or solved.

Under such a scheme of factualizing the world, if implemented and enforced by anyone....Humans would be circular, mechanical, as dogmatic machines and herd animals with no future but that of grass and repetition. Designed and run as a backdrop for leveraging and consumption. A commodity.

Thus, anyone who throws dogma at problems, or refuses to see problems (sees them as non-existent or solved), is either knowingly or unknowingly aiding dogmatic machinations, or is part of the given dogmatic machine as a societal and cultural enforcement.
 
Small rooms and small budgets have meant that I have never had that much below 100Hz in my system, but after 14 years parked in a corner I am close to getting my subwoofer working. Too many kids does slow projects down! Will be interesting to see what I find when I can go flat to 20Hz.

Actually, it doesn't have to go that low, flat to 40 Hz will be just fine. To be sure, lower still would be better, at least you'd have better phase performance, but nothing much in term od sound. Using my normal speakers, I have a flat response to to just below 40 Hz, and when I add my JBL active sub, almost nothing changes, or to be more precise, the difference will be rare on LPs, but a bit more on digital.

If you use a classic FM tuner, beware of possible strong subsonics. Make sure you have a subsonic filter handy.
 
If that includes scalar wave and Schumann resonance generators, I disagree. The second law and Shannon are not sacred cows they're facts as in Mr Tyson's comment "The theory of evolution, like the theory of gravity, is a scientific fact."

The only reality that exists is that there are no facts. That down at the bottom, it is all QED, where it is all subject to integration issues changing the definition of the observation set, in the specific context of the specific observation.

This cascades upward in scaling, into the Newtonian universe and how the Newtonian universe defines itself.

In such a case of averaging of sets (Newtonian world)... it becomes a defined point, be it fact, number, or whatnot --as a label. Underneath the facts, the facts are made out of changing, wandering, slippery marbles that come and go at will, or alter under pressure (observation, etc).

When we talk about facts, they are arbitrary names of averaged conditions for humans to identify as a commonality between humans in communication with the world and themselves.

All of science understands and uses facts everyday, but also has to, when in argument of definition or problem, retreat back to theory. Only then can problems be properly solved.

The danger of factualization is a realization of a circular block on human development and change.

As I've said before, this danger of factualization... is one that is key in human exploration, with regard to eliminating and defeating the machination that lies hidden within the idea and expression of facts.

Science is not religion (as facts are dogma).... unless you wish to dole out death and punishment for anyone who explores and brings in new things to the world.

The least of the crime of factualization is the murder of humanity's future in the act of change and increase.

The faltering point or the exploitation point in this scenario, is the one where the given wired mind uses facts for self comfort (extending it into the world to feel comfortable) or as a method of controlling individuals or groups.
 
Last edited:
  • Like
Reactions: 1 user
Th only reality that exists is that there are no facts. That down at the bottom, it is all QED, where it is all subject to integration issues changing the definition of the observation set, in the specific context of the specific observation.

Somehow I knew this was coming.;)

http://www.irishtimes.com/business/...ry-causes-a-stir-in-dublin-pub-test-1.2211622

Ken don't miss this, it's been how many years?

Steorn is planning a live webinar on October 28th, to discuss and demonstrate their new Orbo PowerCube device. According to the announcement, Shaun McCarthy will be answering questions, "The various components of the Powercube will be shown and how they work together will be explained", and most intriguingly, "there is also a possibility the Powercube will be offered for sale" at some point during a planned series of webinars, of which this will be the first.
 
Last edited:
Member
Joined 2014
Paid Member
Actually, it doesn't have to go that low, flat to 40 Hz will be just fine. To be sure, lower still would be better, at least you'd have better phase performance, but nothing much in term od sound. Using my normal speakers, I have a flat response to to just below 40 Hz, and when I add my JBL active sub, almost nothing changes, or to be more precise, the difference will be rare on LPs, but a bit more on digital.

That's why I think miniDSP will either be a boon or drive me mad. I can have 4 EQ's pre-saved on the vol-FP which should cover most scenarios.
 
diyAudio Member RIP
Joined 2005
Having been in a university research environment for close to 25 years, I can only add, well said.
I only managed 17 years, and left when my designs were vetted by a manipulative crook from Cornell who didn't want his specious claims to having the best IR detector preamp challenged. His technical prowess could be assessed in various ways, including his derisive denunciation of my description of a charge amp reset circuit that used a teeny RF part whose Icex leakage was already less than 100fA at room temperature, much lower cooled: "Femtoamperes?? In this business we are concerned with tiny currents: picoamperes!!" The guy I was doing the work for defended the guy and admonished me for remarking that femtoamps were a thousand times smaller than picoamps. Yet the guy prevailed, and prevented me from doing a pulsed-reset preamp, saying that it wouldn't work --- this after a system using a silicon diode array was up and running and doing science.

I could have picked a better place to go than my family business though, where my somewhat-dysfunctional siblings were a necessary feature. But I learned a lot.
 
I could have picked a better place to go than my family business though, where my
somewhat-dysfunctional siblings were a necessary feature. But I learned a lot.

After some time, I finally realized it's best never to work with (or loan money to) relatives.
Even the Koch brothers had troubles. At least Apple's finally going to pay the vig to our WARF.
 
Last edited:
Status
Not open for further replies.