John Curl's Blowtorch preamplifier

Status
Not open for further replies.
john curl said:

Look, Jneutron has been picking at me for many years, even on other websites.


That explains.


john curl said:

Now, just for fun, last week, as my associate and I are finishing up a new phono preamp, I decided to see IF I could still measure wires with my test setup.


Thank you John for sharing your experience.
Concerning audio, I'm interested less in measurements, my main interest is in audible differences. I have a keen ear – which costs me much money in audio gear – and I do heat differences between cables. When I try cables for my setup, I choose them according to how they sound, not how they measure. Anyhow, I don't have proper measuring tools.
BTW, my speakers cables and most of my interconnects are VDH.
 
Interesting point, however let me also say that I am resolving the distortion waveform with an HP3563 fft analyzer that has precise measurement capability. I only look at the signals that fall right on the line, most of the time, so this 8th harmonic would be 45KHz, in my case. Next time I measure, I might resolve it to 45.125KHz or something like that, but it will be exactly 8 times the fundamental of the test tone.
 
john curl said:
One $1000/meter coax cable that I tried, generated 8th harmonic. Why 8th harmonic at levels less than 50mV? When I replaced it with a VDH cable of the same length, the 8th harmonic went away. When I put back the expensive cable, it reappeared.

I hope you didn't pay $1000 for it.

John - why don't you sketch out your test well enough so we can try to duplicate it in our labs? The AP should do well enough to equal the ST these days.

8th without 2nds or 4ths? Physically unlikely in a weakly non-linear medium. But then again the Blacklight Power guys made CNN.
 
Good question, I suspect that it is complex, but I can't open it easily. However, I find plenty of differences between 75 ohm coax cables, even though maybe not 8th harmonic, It might be 7th harmonic, 6th harmonic, 9th harmonic, or a combination. My residual is such, that I don't bother with the 2nd or 3rd harmonic in these wire tests, AND I have to signal average at least 25 times to get the noise out.
 
john curl said:
You ask too much of me. Try it yourself, or just go with the flow. I have a 256K clock in the HP I am pretty sure. My normal test signal is very very close to 5KHz.

I didn’t mean to ask too much, but it would be interesting to know if you did that test, just to figure out what happened and why it happened.

And I surely don’t go with the flow.’

Stinius
🙂
 
Cable Testing

John:
This is probably getting a little off topic but:
I think I have everything necessary to duplicate your tests, but I need a few more details to do it. And some insight on the mods to the ST. As for looking at the output of the ST I have plenty of options.

I think the questions would resolve to fisrt confirming that distortions on this level exist and then discerning the mechanisms. If we can duplicate the experiment then the second phase could be very interesting.

I have not been able to measure distortions on cables before but I'm very interested in a new way to look.
 
andy_c said:
Sorry if these links have been posted before, but the cable distortion topic has already been hashed out at length here and here.


Thank you Andy for the links.
Since so many people do hear differences between cables, including me and friends of mine, whose hearing I trust – the question in mind is whether science today has the complete data concerning how audio gear's measurable performance impacts human listening experience. There is a genuine question mark in my mind.
 
Re: Cable Testing

1audio said:
John:
This is probably getting a little off topic but:
I think I have everything necessary to duplicate your tests, but I need a few more details to do it. And some insight on the mods to the ST. As for looking at the output of the ST I have plenty of options.

I think the questions would resolve to fisrt confirming that distortions on this level exist and then discerning the mechanisms. If we can duplicate the experiment then the second phase could be very interesting.

I have not been able to measure distortions on cables before but I'm very interested in a new way to look.

Of course, just when you thought it was safe to get into the water.... I had to go and make a mockery out of the entire staid methodology. I had the audacity to create something that is near impossible to measure and when you do measure it..the numbers are useless and inapplicable. Heh Heh heh........ Just my idea of fun and creating little 'posers' for folks.
 
jneutron said:


It would appear that the initial teachers I had are all dead..:bawling:


John you inspired me to do a little googling. Fr. Hilbert (no relation) taught me algebra in 1965. I had an old school Jesuit education, nothing like it.

"Fr. Bob Hilbert, SJ, featured on the cover of this magazine, who at 78 goes vigorously about his work with the Arapaho at St. Stephen’s Mission in Wyoming and doesn’t want to think about slowing down. He will celebrate 50 years as a priest in 2006. Asked by a friend on his birthday years ago what it felt like to turn 70, Bob replied, “Like 16 with worse skin.”"
 
john curl said:
Look, Jneutron has been picking at me for many years, even on other websites. I tried to make him a colleague, from the first,

You are not speaking the truth. The truth is available within the archives of audioasylum for all to see if they so desire. You were the attacker.

In discussions I had with Bob Crump, I learned much about you. From that point on, I ignored your attacks on my character, and attempted to be nice to you.

That has been of no use, unfortunately.

john curl said:
but I found that he ignored any book that I recommended, that he attacked colleagues of mine, such as Dr. Hawksford and Dr. VandenHul

I detailed exactly, all the errors in Hawksford's article. It is unfortunate you neither understood them, nor sought out somebody who did.

And I did so without attacking the man, he is a wonderful and excellent person, a virtual bear in his discipline.

Van de hul? When did I attack him??
Remember, critical review of another's work is not attacking the individual.

You play the martyr well, JC. It is indeed tiresome.

I'll go into detail tomorrow on why AP uses a transformer...and I will re-hash why your ST setup has problems with contact resistance. remember that discussion from years ago??

Stop playing the martyr John, get with the program..

Cheers, John
 
scott wurcer said:


John you inspired me to do a little googling. Fr. Hilbert (no relation) taught me algebra in 1965. I had an old school Jesuit education, nothing like it.

"Fr. Bob Hilbert, SJ, featured on the cover of this magazine, who at 78 goes vigorously about his work with the Arapaho at St. Stephen’s Mission in Wyoming and doesn’t want to think about slowing down. He will celebrate 50 years as a priest in 2006. Asked by a friend on his birthday years ago what it felt like to turn 70, Bob replied, “Like 16 with worse skin.”"

I just spoke with 6 post docs from my old alma mater...on site for research..

Everybody I knew, they did not..


Sigh..

Cheers, John
 
Re: Cable Testing

1audio said:
John:
This is probably getting a little off topic but:
I think I have everything necessary to duplicate your tests, but I need a few more details to do it. And some insight on the mods to the ST. As for looking at the output of the ST I have plenty of options.

I think the questions would resolve to fisrt confirming that distortions on this level exist and then discerning the mechanisms. If we can duplicate the experiment then the second phase could be very interesting.

I have not been able to measure distortions on cables before but I'm very interested in a new way to look.

Be very careful with any ground loops. Apparently AP breaks it with a transformer. John picks up all nearfield E/M as well as the artifact he is attributing to the cable.
Cheers, John
 
Status
Not open for further replies.