OT
We should stick to the term acoustical polarity in contrary to phase consideration, as there is no phase shift that does the same to asymmetrical waveforms what a polarity switch does.
I have to reread the Schroeder paper, but afair it was in ?1951-1952? first described by an author named wood?!
That´s the reason why Clark Johnsson named his book `the wood effect`. Afair his convention preprint listed a couple of references.
Jakob2
We should stick to the term acoustical polarity in contrary to phase consideration, as there is no phase shift that does the same to asymmetrical waveforms what a polarity switch does.
I have to reread the Schroeder paper, but afair it was in ?1951-1952? first described by an author named wood?!
That´s the reason why Clark Johnsson named his book `the wood effect`. Afair his convention preprint listed a couple of references.
Jakob2
Whether it suits folks or not, the term absolute phase has been around so long that it's just going to cause confusion if you start calling it anything else. Just treat it as grandfathered in. On the day they change ammonia's formula to H3N (how the devil do you get subscripts out of this confounded thing?), then we can talk about changing the name of 'absolute phase.'
Grey
Grey
First things first. IF we can get Dimitri to post the 1975 Schroeder article here, then we can discuss what was known as far back as 1/3 century ago. This is an amazing amout of info, that supercedes, 'OHM's Law of Acoustics' still written about 70 years ago as gospel. (Where do you think that Paul Klipsch got his hard core beliefs?)
GRollins said:
The term "absolute phase" causes confusion, see Linkwitz use of this term:
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The crossover as described is phase coherent, in that the phase of each signal applied to each loudspeaker driver is essentially in phase with all other signals that have passed through the crossover. Because filters are used, the crossover is not phase neutral - there are wide variations in absolute phase as the frequency changes. This is the case with all crossover networks, from the simplest to the most complex, active or passive.
-----
Semantic, again. Acoustical polarity is clear.
Re: Oh yes..why I ended up in this thread in the first palce......
Bueller? Bueller?
Not the world's toughest question, like the best scotch, the best beer, or best looking woman. Not toooo tough... just very argumentative.
OK. How about this: Who has the best range of adaptable or, 'well behaved' transformers, overall? There's only so many manufacturers.
KBK said:
Bueller? Bueller?
Not the world's toughest question, like the best scotch, the best beer, or best looking woman. Not toooo tough... just very argumentative.
OK. How about this: Who has the best range of adaptable or, 'well behaved' transformers, overall? There's only so many manufacturers.
@ GRollins,
i´m sorry about that, but `acoustical polarity`(or absolute polarity) is the term known in the literature on this subject just to avoid any confusion to phase related discussions.
Clark Johnsen wrotes about the so called `wood effect´in this webpage:
http://www.positive-feedback.com/Issue1/cjwoodeffect.htm
The AES-Convention preprint (with extended reference list also citing the mentioned paper from the 1950s):
Proofs of an Absolute Polarity by Johnsen, Clark
Paper Number: 3169 AES Convention: 91 (October 1991)
Another interesting paper on this was:
Greiner & Melton, "Observations on the Audibility of Acoustic Polarity" Journ. Audio Eng. Soc. Vol 42 #4, April 1994.
Monforte & Karley wrote some additional remarks in this issue.
@ John Curl,
But if my memory serves me right, Schroeder showed that ohm´s law of the human phase deafness was wrong and it might be related to the topic of acoustical polarity too but i´m not sure in this point.
Jakob2
i´m sorry about that, but `acoustical polarity`(or absolute polarity) is the term known in the literature on this subject just to avoid any confusion to phase related discussions.
Clark Johnsen wrotes about the so called `wood effect´in this webpage:
http://www.positive-feedback.com/Issue1/cjwoodeffect.htm
The AES-Convention preprint (with extended reference list also citing the mentioned paper from the 1950s):
Proofs of an Absolute Polarity by Johnsen, Clark
Paper Number: 3169 AES Convention: 91 (October 1991)
Another interesting paper on this was:
Greiner & Melton, "Observations on the Audibility of Acoustic Polarity" Journ. Audio Eng. Soc. Vol 42 #4, April 1994.
Monforte & Karley wrote some additional remarks in this issue.
@ John Curl,
But if my memory serves me right, Schroeder showed that ohm´s law of the human phase deafness was wrong and it might be related to the topic of acoustical polarity too but i´m not sure in this point.
Jakob2
John,
I have a real Blowtorch question. You are designing a component that has to at least some universal applicability. What about line stages when one knows they only have a foot of cable and a 50K volume control to drive? BTW I really do like your little 6 transistor cell. Its transfer characteristic mimics the basic transducers, good Karma.
I have a real Blowtorch question. You are designing a component that has to at least some universal applicability. What about line stages when one knows they only have a foot of cable and a 50K volume control to drive? BTW I really do like your little 6 transistor cell. Its transfer characteristic mimics the basic transducers, good Karma.
john curl said:
My understanding is that you cannot post whole articles here.
However, if Dimitri or anyone else wishes to scan the article and then send it to anyone who requests it, that is allowed.
I have done this with several articles. In order to save time and effort, I don't bother with Optical Character Recognition software or pdf'ing. I just save each scanned page as a separate GIF and then sent them to anyone who wanted them. This is the equivalent of getting a Xerox copy of each page, and fulfills the purpose just fine.
But of course, it is up to the person with the article to see if he has the time. Or if someone with broadband wants to help out and become the "distributor", that is also fine.
I replaced my 10 turn wire wound dual pot with 1 ft of quality cable with the Blowtorch. It worked OK, but the Blowtorch is better, maybe because it offers a consistent 1K drive impedance, rather than a varying impedance that the pot gives directly.
IF all you need is a pot, then do it. If you need switching, polarity selection, component selection, and even a phono stage, then the CTC Blowtorch was a good way to go, IF you had the money to purchase it. I just sold the last Blowtorch this week. The money is in my bank account, and no more will be made. It justs costs too much time and effort to do it.
Just yesterday, Jam was 'annoying' me again about purchasing CTC Blowtorch circuit boards. He will be very unhappy with what I will have to charge him. I know what time and effort it takes to make something that really 'glows' and that is what I prefer to concentrate on. You, Scott, can make brilliant circuits, and your marketing department can rip the rest of us off with a cost to markup ratio of 10 or much more, while I can only charge for my time and effort. Who is offering the 'best' price?
For everyone else, I picked up a copy of 'Hi Fi +' Issue 56, and saw a quality picture of a Breuer Tone Arm that I used for 14 years, before it was destroyed in a firestorm in 1991. If anyone out there has a copy of this mag, then look at page 25 at the picture of the Breuer arm. I know Herr Breuer and have visited his machine shop. I still MISS that arm, after 16 years without it. That is what is called 'quality' rather than manufacturability. (Don't worry Scott, the price for a newstand copy is $11, out of your interest range, I suspect.)
IF all you need is a pot, then do it. If you need switching, polarity selection, component selection, and even a phono stage, then the CTC Blowtorch was a good way to go, IF you had the money to purchase it. I just sold the last Blowtorch this week. The money is in my bank account, and no more will be made. It justs costs too much time and effort to do it.
Just yesterday, Jam was 'annoying' me again about purchasing CTC Blowtorch circuit boards. He will be very unhappy with what I will have to charge him. I know what time and effort it takes to make something that really 'glows' and that is what I prefer to concentrate on. You, Scott, can make brilliant circuits, and your marketing department can rip the rest of us off with a cost to markup ratio of 10 or much more, while I can only charge for my time and effort. Who is offering the 'best' price?
For everyone else, I picked up a copy of 'Hi Fi +' Issue 56, and saw a quality picture of a Breuer Tone Arm that I used for 14 years, before it was destroyed in a firestorm in 1991. If anyone out there has a copy of this mag, then look at page 25 at the picture of the Breuer arm. I know Herr Breuer and have visited his machine shop. I still MISS that arm, after 16 years without it. That is what is called 'quality' rather than manufacturability. (Don't worry Scott, the price for a newstand copy is $11, out of your interest range, I suspect.)
john curl said:(Don't worry Scott, the price for a newstand copy is $11, out of your interest range, I suspect.)
John, I'm a junk box cobbler at heart and always will be. I still get down on the floor every time I drop an SMT resistor. Most magazines these days don't last through one trip to the outhouse.
I meant what kind of line stages do you think would work best when you know the load is light.
A simple matched jfet follower. Bob used that for years in the CTC chassis, before I designed its replacement. OPEN LOOP, GOOD! 
john curl said:
Agreed. I put two in, one ahead and one behind, volume control in between. As long as you don't need gain, you're good to go. I posted same in GR-25 thread and am still amazed that there aren't a dozen other threads about such a nifty circuit.
Grey
Not the best solution. Use one jfet for current source load. Not necessary to put in front, just more distortion.
Funny you should mention, I have a nice article about these
buffers scheduled to be out shortly.
😎
buffers scheduled to be out shortly.
😎
Good Nelson, I think that these little buffers can be very good for many things. Bob Crump developed the whole CTC setup with these little buffers, before he had me come in and make a balanced stage with some gain. He selected the case, the switches and the TKD pots way back. I only came into the picture with the balanced line stage, power supply, and phono modules.
This says a lot for the simple dual fet buffered multiplier.
I used this circuit since 1971 when I used it with my B&K 1" capsules. Still have one working today. One thing that I found was that I could cancel the 2'rd harmonic distortion by using the right active device for the current load, leaving a very pure output.
Of course, MATCHED jfets give you zero input and output offset as well.
Back in 1970, I experimented with complementary jfet followers, and used them with some Grateful Dead projects and in the Levinson JC-2 phono preamp stage, but they have a real weakness, OFFSET. I suspect that IF I could servo out the offset, that might be an even better buffer for real experts like us. Tough design for amateurs, I should think.
This says a lot for the simple dual fet buffered multiplier.
I used this circuit since 1971 when I used it with my B&K 1" capsules. Still have one working today. One thing that I found was that I could cancel the 2'rd harmonic distortion by using the right active device for the current load, leaving a very pure output.
Of course, MATCHED jfets give you zero input and output offset as well.
Back in 1970, I experimented with complementary jfet followers, and used them with some Grateful Dead projects and in the Levinson JC-2 phono preamp stage, but they have a real weakness, OFFSET. I suspect that IF I could servo out the offset, that might be an even better buffer for real experts like us. Tough design for amateurs, I should think.
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