Warning, facetiousness ahead.
I had some wire and I wanted to test the effects that placing magnetic materials near the wire would have on the current flowing through it. I coiled the wire up so as to take up less room. I passed a sinusoidal voltage through the wire, and used a shunt resistor to measure the current. The current was in phase with the voltage, but as I placed a powdered iron core into the coil the current began to lag the voltage, as seen on my oscilloscope. As I increased the frequency the lag in current became greater.
I had some wire and I wanted to test the effects that placing magnetic materials near the wire would have on the current flowing through it. I coiled the wire up so as to take up less room. I passed a sinusoidal voltage through the wire, and used a shunt resistor to measure the current. The current was in phase with the voltage, but as I placed a powdered iron core into the coil the current began to lag the voltage, as seen on my oscilloscope. As I increased the frequency the lag in current became greater.
SY, I have these gold plated KOVAR leaded precision resistors here for $1 each, just for you. Such a deal! Better deal than 3-Buck Chuck!
Please put your money where your mouth is?
Please put your money where your mouth is?
Money? You'll have to ask my ex-wives.😀
You'd get a kick out of seeing what I used in my preamp. Next time I come over, I'll haul it along, as long as you promise not to be offended by all those damn tubes.
You'd get a kick out of seeing what I used in my preamp. Next time I come over, I'll haul it along, as long as you promise not to be offended by all those damn tubes.
Up next.........The Buffered Blowtorch?
..................maybe at some point this thread will get back on track.
As I see it we have Mr.Curl and Mr.Hansen, who many have seem to forgetten, have years (maybe decades.....especially Mr.Curl) of design expirence and have been kind enough to share some of their observations with us and the naysayers led by Sy and company who would like to disagree because they were taught differently and insist they are right because some text says so. (......was it true that our ancestors knew for a fact that the earth was flat?)
The funny thing about this is that they don't seem to have any practical experience with some issues that have been brought up. ............If you can't measure it cannot be happening.................What if the technology to measure it won't be available for twenty years...........do you halt progress till then ....................or is it safer to ignore it if you can't explain it..................
Mr.Hansen has showed me a few things that have changed my system. Some have been subtle and some been huge and sometimes they have been to the detriment of the system but always identifible but impossible to measusure
My hat is off to these gentlemen for daring to question the unknown to advance the art and to the others maybe it it better you keep your opinions after all they say that Ignorance is Bliss.
Jam
..................maybe at some point this thread will get back on track.As I see it we have Mr.Curl and Mr.Hansen, who many have seem to forgetten, have years (maybe decades.....especially Mr.Curl) of design expirence and have been kind enough to share some of their observations with us and the naysayers led by Sy and company who would like to disagree because they were taught differently and insist they are right because some text says so. (......was it true that our ancestors knew for a fact that the earth was flat?)
The funny thing about this is that they don't seem to have any practical experience with some issues that have been brought up. ............If you can't measure it cannot be happening.................What if the technology to measure it won't be available for twenty years...........do you halt progress till then ....................or is it safer to ignore it if you can't explain it..................
Mr.Hansen has showed me a few things that have changed my system. Some have been subtle and some been huge and sometimes they have been to the detriment of the system but always identifible but impossible to measusure
My hat is off to these gentlemen for daring to question the unknown to advance the art and to the others maybe it it better you keep your opinions after all they say that Ignorance is Bliss.
Jam
Please show me where I ever said that.
BTW, I wasn't "taught differently." I have always been upfront about the fact that I have absolutely no engineering training whatever. None. Zero. Zip.
Sy,
..............I never said that you said it, I implied that seemed to be the attitude of the naysayers.😉
On a different note, I find Mr.Curl's reference to you making bottle caps for a living totally out of line.😀 .........some of my best friends.............😉
Regards,
Jam
..............I never said that you said it, I implied that seemed to be the attitude of the naysayers.😉
On a different note, I find Mr.Curl's reference to you making bottle caps for a living totally out of line.😀 .........some of my best friends.............😉
Regards,
Jam
Re: Re: Re: Re: On jfet followers
Hi Scott,
I don't have a simulator package but I do have a bag of 2SK170BL JFETs. I also have a growing desire to experiment with this circuit. I will assume that an Id of 3-5ma would be reasonable. Could you please suggest some starting values for the bias voltages and resistors. Many thanks.
Graeme
scott wurcer said:
Hi Scott,
I don't have a simulator package but I do have a bag of 2SK170BL JFETs. I also have a growing desire to experiment with this circuit. I will assume that an Id of 3-5ma would be reasonable. Could you please suggest some starting values for the bias voltages and resistors. Many thanks.
Graeme
SY, I will GIVE you 10 selected values of these special resistors. If you decide you want more, fine.
john curl said:
We tested different output impedances for several years, and the result of listening tests was that something like 5 ohms was a winner. We tried output impedance same as cable characteristic impedance and we tried matched cable as well. Finally, it was few ohms as a winner. Output stage of the preamp is robust, see square 7kHz into 1uF, the output impedance is 3 ohm in this case.
Attachments
Then, PMA, you would say that it doesn't matter if we are actually near the characteristic impedance of the cable at ANY frequency. You are about 12 times away, as I am, from some sort of optimum matching of a generic cable Maybe you are right, maybe Charles (and Dick Marsh who told me this 25 years ago) is right, and maybe, just maybe I would rather try to get away with a zero global feedback design of only 1 and 1/2 stages, rather than 2 stages like Charles.
Maybe I would say that for some reason, and I really do not exactly know why, there is a parallel with power amplifiers - the more powerful and robust output stage sounds better, if properly designed.
SY said:
If you have some ferromagnetic endcaps in a fairly low impedance
resistor, I think we could show that without difficulty.
SY said:
I THINK Bruno Putzeys included some copperweld coaxial cables in some of his cable measurements and didn't turn up anything. I seem to recall Dan Banquer using it as vindication of his use of copperweld in his RE Designs gear. I'll have to poke around and see if I can find a specific reference for it.
se
John, thanks- I'll take you up on that and do what Nelson suggests. Nelson, by "low impedance," what do you mean? 10R? 100R? 0R1? Suggested test frequencies? THD, IM, or what? (Sorry, I'm full of questions today)
Jam, as you know, John and I are friends so there is absolutely no problem. Doing wine packaging for a living taught me a great deal about methods and pitfalls in sensory research, a nice complement to the haptics stuff I did before that. I'm a little buggy about unqualified sensory claims without backup evidence, but I come by that professionally- my customers expect my products to perform significantly better than my competition in controlled subjective tests. I'm still amazed that Charles's, John's, and Nelson's customers don't.
Jam, as you know, John and I are friends so there is absolutely no problem. Doing wine packaging for a living taught me a great deal about methods and pitfalls in sensory research, a nice complement to the haptics stuff I did before that. I'm a little buggy about unqualified sensory claims without backup evidence, but I come by that professionally- my customers expect my products to perform significantly better than my competition in controlled subjective tests. I'm still amazed that Charles's, John's, and Nelson's customers don't.
Steve, wasn't there someone selling speaker cables made from mu metal or something like that?
Ok. Seems I was the one who sent Bruno the copperweld cables which I think Dan Banquer had sent me. It was written up over on Audioholics.
Cable Distortion and Dielectric Biasing Debunked - Page 2
se
Cable Distortion and Dielectric Biasing Debunked - Page 2
se
SY said:
I believe Dave Magnan was doing some interconnects using MuMetal. And a company in the UK called Black Rhodium was making interconnects made out of pure nickel. Either of these may also have made speaker cables using ferromagnetic conductors but I don't recall them specifically.
se
SY said:
The lower the resistance, the easier to see it, and it tends to show
up a higher frequencies.
If I used something like 10R and 10kHz, would you expect to see the effect? My measurement limit is 0.002% or so for THD, 0.004% or so for IM.
Steve, thanks for the link.
Steve, thanks for the link.
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