No thank you Andrew. I do what I do for commercial purposes. I have 1000's of power amps out there, and sometimes one gets into trouble. I hope the the person with a problem duly reports the problem to Parasound, so that we can know about it and address it.
whitlock lectures.
Have the two lectures been taken off the web?
I got through one and a half.
But Today I cannot get either back up.
Have the two lectures been taken off the web?
I got through one and a half.
But Today I cannot get either back up.
I can't duplicate the test comparing coils vs no coils The tester has been dead for about 10 years, and I never wrote down the test procedure.
Looks like the AES uses some weird "security system" to protect views from non-members. The lecture is still availble to members but the URL changed. Why not become a member? It's not expensive and you'll get access to tons of valuable info.
I don't want to badger you, just trying to avoid prejudice 🙂 But kicking out the coils without telling people for which application the Parasound amp was designed for was probably a bad design decision.
The Parasound amps are considered unconditionally stable with virtually any load, but apparently there are some exceptions. Certainly better than the Marantz 14 that I bought in 1969.
I might comment on what I found to be the most difficult cable that I have ever used. It was the so-called Polk Cable, introduced in the late '70's. It was worse than an single cap, but apparently it could be fixed with an external Zobel network on its far end. Perhaps that is why so many hi end cables have networks at the far end of the cable.
So i'm assuming that they'll be even happier driving a driver directly? IE no crossover network? Or is this verboten 😎
Generally, I try to make the amps stable from the output terminals. I normally just do the cap stability test described previously. It usually works with just about anything.
Then I will repeat my initial statements..
""His tutorial on magnetic induction, ground loop topology effects, transmission line theory and application are rudimentary and incomplete. It is interesting to see mis-conception at this level. I was hoping for better.
He states that he searched for information on where that loop voltage comes from. He did not do a very good search. I initially posted on five different forums, starting May 4, 2004, with many posts on this since.""
I have detailed exactly where the loop current comes from, you know, the 58 milliamps he searched the web for an explanation to no avail? (Note that he used a low bandwidth clamp on meter...why did he not use a 100 Khz clamp on and evaluate the ground loop current while the power amp was pulling a kilowatt of music-modulated haversine currents??
I invoked Faradays law of induction (in other words, magic) and detailed where the magnetic flux comes from, how it is trapped in the loop, what affects the final loop current. Bill at least included the proportional to frequency aspect..but stated incorrectly that once the currents are in the chassis, it's ok...IT'S NOT...at low frequencies, the path reluctance and current spreading limit the induction to the sensitive circuits, but as frequency goes up, the current density increases as the current crowds the lowest impedance path..This, he needs to learn.
I detailed what parameters affect the loop current...integrated flux, rate of change of flux, path resistance including the romex ground, the line cord grounds, the IC grounds, all the connector contact resistances..
edit: A learned reader would realize that the last three paragraphs, when combined, forms the electromagnetic theory basis for a line cord and/or IC affecting the sound..
It is of no concern to me whether you understand what I speak of, or if you care enough to learn. You are welcome to ask me via pm, or search to learn what I speak of. It is all within this forum.
I was surprised to learn that Bill was unable to discover my posts on these topics, and that the magnetic understanding of ground loops is still rudimentary at his level. As a starting point, he would be well served by a course in EMC, perhaps Tom Van Doren's class, before reading my posts.
Cheers, John
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jneutron
I too would like to repeat myself. Why don't you just do a writeup and post it on a webpage so others might respond in a more objective fashion?
It would save everybody a lot of time and surprises. If you want to educate people one at a time, you will need to have a lot of time on your hands. And each day new people are born that need to start from scratch. Just because Einstein knew something doesn't automatically mean that all people following will have that knowledge too.
Posting something on a forum doesn't guarantee that anybody will read it because a forum is not an archive (although a lot of people think of it that way). Wikipedia would be an option but everybody is allowed to edit your text .
Best, Markus
I too would like to repeat myself. Why don't you just do a writeup and post it on a webpage so others might respond in a more objective fashion?
It would save everybody a lot of time and surprises. If you want to educate people one at a time, you will need to have a lot of time on your hands. And each day new people are born that need to start from scratch. Just because Einstein knew something doesn't automatically mean that all people following will have that knowledge too.
Posting something on a forum doesn't guarantee that anybody will read it because a forum is not an archive (although a lot of people think of it that way). Wikipedia would be an option but everybody is allowed to edit your text .
Best, Markus
Hi Marcus. I did indeed consider wiki, but agree with you about the editing issue.
Using the forums as an archive works quite well, but one needs sufficient key words to limit frustration.
I've also found that google will hit posts in the forums rather well, but again key words are an issue.
When I retire, I may take up the cause.. For now, I marvel at the lack of E/M field rigor at Bill's level. Quite honestly, I find his presentations and discussions among the best out there, but am unhappy with how far he has to go.
I had inquired about setting up a permanent page on several forum sites along these lines to no avail..they would have provided a more focussed target audience. And given the level of EM field theory understanding I see at AES... Bill's talk for example, I have no desire to join or present there.
Cheers, John
Using the forums as an archive works quite well, but one needs sufficient key words to limit frustration.
I've also found that google will hit posts in the forums rather well, but again key words are an issue.
When I retire, I may take up the cause.. For now, I marvel at the lack of E/M field rigor at Bill's level. Quite honestly, I find his presentations and discussions among the best out there, but am unhappy with how far he has to go.
I had inquired about setting up a permanent page on several forum sites along these lines to no avail..they would have provided a more focussed target audience. And given the level of EM field theory understanding I see at AES... Bill's talk for example, I have no desire to join or present there.
Cheers, John
By the way, it's Markus with a k. Since moving to the States I still wait for people to recognize that fact. Obviously seeing it in every single post does not educate people a lot 🙂
I was going to suggest the same thing. We actually pay for articles by experts like Mr. Neutron.
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