There are some that have Ccomp split, yes. My point here was that adding bypass from the plus rail to ground always made the diff-phase worse. BTW diff-phase is probably the most sensitive of all closed-loop parameters to GBW modulation. This circuit is otherwise the simplest textbook CFA with shunt Ccomp to (if it was there) ground. Funny that folks have not seen it before it was designed specifically for the, at the time, biggest maker of analog video distribution boxes a now virtually obsolete business.
You are right, but
If we are interested in qualities, then I think it's too bad that test fell out of use because it helps in overcoming the problem of habituation. And gives a chance to identify deficiencies.
Member
Joined 2009
Paid Member
Good observation. I have a tube amp project that has a power supply which is expected to behave in this manner. I've rarely seen much talk about this approach though. But tube amps with inductor based power supplies can allow some fine tuning of their 'step response'.
No, it isn't the wire in question. It is simply a wire. The initial questions were about the coiling of microphone wire and how it made the sound terrible due to the increased inductance caused by the solenoidal currents within the twisted pair.
My contention is that there is no solenoidal magnetic field as a consequence of coiling a microphone cable. There may be other effects caused by the inherent communication capability of a twisted pair cable to conductice materials in its immediate environment, and coupling to other twisted cables with the same or integer related twist pitch (including itself.)
What is in question, is what were the conditions of the test. That is being kept secret so that it will not be possible to duplicate the results.
That's not how real engineers work.
That is not how I work.
jn
ps. now if that ain't a lob right over the plate, I don't know what is..
Last edited:
Since there is in essence no experiment to parallel what is he to do in response? Remember 3+ orders of magnitude of error remain on the table.
I see we share a snub by Dr. Rich, I told him I respect people's enjoyment of SET's and horns and he never talked to me again.
Last edited:
Back up my statement?? I stated that Ed used the wrong meter setting for the test. HE repeated it using the right meter setting and got results that were at least within the same order of magnitude as reality. Of course, with absolutely ZERO specifics on what he took pictures of.
As I said earlier, it is not my responsibility to try to duplicate every test some yahoo on the internet posts.
In Ed's case, he explained a 3 order of magnitude test error as the EXPECTED result.. Do I try to duplicate the test using the same incorrect instrument settings??
Do I try to duplicate a few pictures of a meter, without regard to what's connected to it, or how the test is performed?
After I explained to Ed why his test settings were incorrect, HE at least had the balls to re-do the test and provide pictures. Granted, he never acknowledged that he really screwed up the test by using the wrong settings, and he never acknowledged that his explanation of the 7 millihenries was made up fiction reinforced by a bad reading 1000 times larger than reality.
You on the other hand, went off for a year or so explaining to us how your fancy refurbed ST was finding all kinds of non linearities in the connections. No matter how much I explained to you how your equipment was not designed for that level of operation as it didn't clear the ground loop problem you had. Several others used AP's and found nothing, yet you never acknowledged the fact that you were led down the garden path as a result of lack of knowledge on EM compatibility.
Malcolm does the same. Messed up the derivation by using an approximation equation that didn't even apply to the problem, forgot to add the wire permeability and it's inductive increase to the wire, had absolutely no clue as to how to make an actual test fixture capable of high rate of current slew without large voltage errors, and from then on, refuses to acknowledge 27 YEARS later, that he messed up big time..
Is that what you are all about John? Is that what your part in high end audio is all about? make up some unsubstantiated scientific explanation, put together some hilariously bad and incompetent test design, cherry pick the results which fit your premise, the present the "proof" with absolutely no information which would allow others to reproduce your "results"?
I will perform CONTROLLED, baselined, accurate measurements of my cable when I get to it. And I will detail the exact conditions of the test.
Just as I did with the cable test in my gallery, just as I did with the inductor tests also in my gallery.
jn
Last edited:
I guess you too are happy with test errors of three orders of magnitude as long as they support your beliefs?
As an engineer, I cannot do that.
I also note with interest that you do not concern yourself with how your amp actually works with the equipment it is designed to work with. You appear most happy to present bench testing as the endall, without consideration of how is actually performs in the field.
JohnC doesn't even know HOW his equipment is tested, case in point the crosstalk testing.
It frightens me that others may be learning this craft from people who do not believe rigorous engineering practices are important..
With luck, the next generation of engineers will consider the actual use, as opposed to only bench testing that you seem enamored of. If that doesn't happen soon enough, high end will continue it's slide into oblivion and fashion.
jn
Last edited:
Continue? You mean it could get worse? Even more nonsense propagated as 'a superior truth'?jneutron said:
How can we convince people that a number on a meter or a trace on a screen tells us precisely nothing unless we have a good theory (a prerequisite for good experimental practice) about what we thought we were 'measuring'. A quick check would be to ask for estimated error bars on the 'measurement'. If the error bars are several orders of magnitude larger than the 'measurement' then we have just invented yet another random number generator.
I trust Stereophile to give me ACCURATE RELATIVE RESULTS compared to my competition that is measured in the same way. Once we actually build a product, we can do little to fix things like Xtalk. We have to start circuit layout stage, and be in CONTROL of the whole fabrication process. As we do NOT always have that with Parasound products, we have to live with what we get from Taiwan. This is why PMA built his own amp, so as to have control over layout and construction. It sure beats a SW Products power amp. '-)
- Status
- Not open for further replies.