Well the analogy is beside the point. Why not set out how quadrature phase solves the problem? Enquiring minds want to know
<edit> For those interested in capacitive solutions, this paper sets out some methods : http://www.capsense.com/capsense-wp.pdf
<edit> For those interested in capacitive solutions, this paper sets out some methods : http://www.capsense.com/capsense-wp.pdf
Last edited:
laser Doppler velocimetry typically uses a frequency offset - see Bragg Cell acoustoptic modulators
this gives a "FM" signal from the detector
it is also possible to "chirp" diode laser frequency with a current ramp - say a sawtooth with fast retrace - then unequal path lengths give a frequency offset during the ramp
this gives a "FM" signal from the detector
it is also possible to "chirp" diode laser frequency with a current ramp - say a sawtooth with fast retrace - then unequal path lengths give a frequency offset during the ramp
I made a run of preamps for these for the late John Fong,
Precision Fidelity. The single pole integration does result
in some deviation, but no customers seem to have minded,
and it did sound good.
John Iverson was a smart, likable and charming guy, but
he would blow smoke up your poop chute if you let him.
A shame he is no longer around to entertain us.
Im not Joachim, but my complete MC (called the Silver Spirit) is cryogenic treated, has the strongest rare earth magnets available ( no neodymium), precision wound generator, the best possible alignment of tip and cantilever ( aluminium tube), best possible polish and really heavy fullmetalbody (1 ounce for the complete cartridge) and is filled with some antiresonant composite. Stylus is spheric tip.
The whole thing costs at least 9'000.- US $ Retail.
I would buy it againand i never had the desire to change it for something else.
The whole thing costs at least 9'000.- US $ Retail.
I would buy it againand i never had the desire to change it for something else.
Yes, the magnets. Koetzu used rare earth magnets like Alnico or Samarium Cobald. Actually this magnets are not as strong as modern Neodymium but the field is longer and more linear around the coil. The most extrem magnets where made by Nippon Mining and where based on Platinum. Even less strong and even longer field. They are not made any more so when you like to own a Lyra Olypos you have to "donate" a Parnassus. The "sound" of that magnets is very warm and romantic but with good spaciousness and resolution so i bet you whould like it. The Olympos was Jonathan Carr´s last design that used a conventional polepiece. In the Olypos it is made from gold plated high purity iron. Jothatan thought that the polepiece adds distortion so he put two Neodymium rings in the front and back of the coils to avoid the polepiece. Your Delos should have the old polepiece design but your Helicon SL should have the ring magnet design.
I have no experience with Cryo so you have to ask someone better informed about that.
I have no experience with Cryo so you have to ask someone better informed about that.
The manufacturer did not tell me which ones he uses.
Either it will be Samarium Cobalt or Alnico, i don't know.
He avoids neodymium, says the sound is not better, altough the neodymium is stronger, but the field distribution will be different.
Maybe the saturation of the pole pieces is a problem with neodymium-
Abouth cryo, i will ask him if only the cantilever is treated or the whole cartridge.
He says it makes a minor difference, but audible.
Semantic Journey
Except for direct-to-cutter LPs, all LP reproduction has been passed through the sampling of a magnetic record system. Anyone who has performed high-resolution microscopic magnetic domain imaging of magnetic recordings has seen the discrete samples left at the bias zero cross-over points. This makes a magnetic recorder a time-discontinuous sampling system at 2x the bias frequency.
If that isn't non-analog enough for you, consider that if a recorder used a fixed bias system, that inherent sampling interval was modulated by the instantaneous sum of the bias and audio. This is because the size of the bias bubble (nicknamed for it's shape when viewed on axis with the gap) is modulated by it's strength. The magnetism in the domains of the record media only stabilize when they exit the bias bubble. If the bubble is varying in size, this record zone moves laterally back in forth in time along the tape, and is literally a form of jitter, or time base error.
This was the triumph of the Dolby HX system. When the HX detector frequency response curves were carefully adjusted for a specific tape type and static bias point, the sonic result was remarkably superior to a fixed bias approach due to stabilization of this bias bubble. I spent hundreds of hours with Dolby engineers perfecting this system, and the imaging and clarity of pure tones embedded in music, with removal of FM sidebands from the sound was amazing.
The less-than optimum results many obtained from the HX scheme in home recorders was due to the inherent compromise when using a wide range of tape types and bias levels. In the (good old days of the) cassette replication industry we standardized on certain tape formulations (such as TDK APG pancakes, which was the bulk form of SA-X tape) and spent weeks and months tweaking the HX for stable bias. The resulting sound was good enough that Doug Sax of Sheffield chose this process to make his cassettes, as did Telarc and DMP.
I guess my highly belabored point is that unless an LP has been made using a direct-to-cutter process it is not truly the product of an analog signal chain. It is an analog vinyl replica of a series of discrete analog samples which have been integrated by the tape playback system.
Now, don't get me wrong, I am a huge fan of listening to LPs, treasure my multi-thousand LP collection, and listen to some of them every week. The best sound I have heard from my system comes from certain LPs. BUT, from this perspective, WHAT causes the "magic" in an LP? It is not because it is pure analog. I have most of Doug Sax's direct-to-cutter Sheffield titles and they are truly remarkable in their S/N and dynamic range. I would be hard pressed to say that they are leagues ahead of some which he pressed from recordings. This says to me that this discontinuous magnetic recording, warts and all, is not substantially "in the way" of the sound from an LP. Critics would point this out as proof that despite the exteme resolution (to the vinyl molecule level) and dynamic range (better than 20 bits unweighted on some uncompressed LPs), the LP is low enough accuracy to hide the flaws in magnetic recording.
What say y'all? [canofwormsopening.wav]
Howard Hoyt
CE WXYC FM-89.3
UNC Chapel Hill, NC
www.wxyc.org
1st on the Internet
Except for direct-to-cutter LPs, all LP reproduction has been passed through the sampling of a magnetic record system. Anyone who has performed high-resolution microscopic magnetic domain imaging of magnetic recordings has seen the discrete samples left at the bias zero cross-over points. This makes a magnetic recorder a time-discontinuous sampling system at 2x the bias frequency.
If that isn't non-analog enough for you, consider that if a recorder used a fixed bias system, that inherent sampling interval was modulated by the instantaneous sum of the bias and audio. This is because the size of the bias bubble (nicknamed for it's shape when viewed on axis with the gap) is modulated by it's strength. The magnetism in the domains of the record media only stabilize when they exit the bias bubble. If the bubble is varying in size, this record zone moves laterally back in forth in time along the tape, and is literally a form of jitter, or time base error.
This was the triumph of the Dolby HX system. When the HX detector frequency response curves were carefully adjusted for a specific tape type and static bias point, the sonic result was remarkably superior to a fixed bias approach due to stabilization of this bias bubble. I spent hundreds of hours with Dolby engineers perfecting this system, and the imaging and clarity of pure tones embedded in music, with removal of FM sidebands from the sound was amazing.
The less-than optimum results many obtained from the HX scheme in home recorders was due to the inherent compromise when using a wide range of tape types and bias levels. In the (good old days of the) cassette replication industry we standardized on certain tape formulations (such as TDK APG pancakes, which was the bulk form of SA-X tape) and spent weeks and months tweaking the HX for stable bias. The resulting sound was good enough that Doug Sax of Sheffield chose this process to make his cassettes, as did Telarc and DMP.
I guess my highly belabored point is that unless an LP has been made using a direct-to-cutter process it is not truly the product of an analog signal chain. It is an analog vinyl replica of a series of discrete analog samples which have been integrated by the tape playback system.
Now, don't get me wrong, I am a huge fan of listening to LPs, treasure my multi-thousand LP collection, and listen to some of them every week. The best sound I have heard from my system comes from certain LPs. BUT, from this perspective, WHAT causes the "magic" in an LP? It is not because it is pure analog. I have most of Doug Sax's direct-to-cutter Sheffield titles and they are truly remarkable in their S/N and dynamic range. I would be hard pressed to say that they are leagues ahead of some which he pressed from recordings. This says to me that this discontinuous magnetic recording, warts and all, is not substantially "in the way" of the sound from an LP. Critics would point this out as proof that despite the exteme resolution (to the vinyl molecule level) and dynamic range (better than 20 bits unweighted on some uncompressed LPs), the LP is low enough accuracy to hide the flaws in magnetic recording.
What say y'all?
[canofwormsopening.wav]Howard Hoyt
CE WXYC FM-89.3
UNC Chapel Hill, NC
www.wxyc.org
1st on the Internet
Last edited:
Howard, your input is interesting, but misleading. Having designed a number of analog recorders, one thing stands out: AS you reduce level, distortion (3rd almost entirely) reduces right down to the noise floor, without dithering. No digital system that I know, can do this. Perhaps full 32 bit operation could approximate it. I don't know.
Last edited:
- Status
- Not open for further replies.