STC Posted October 23, 2019 Author Share Posted October 23, 2019 On 10/21/2019 at 3:37 PM, STC said: Local scientist modification to CD player. Anyone want to guess why? @fas42 you go first. This was a poor attempt to copy what Krell used to do with their CD players. They used green led to absorb the stray laser light. Perhaps someone got the idea from there to come up with the green pen marker. Knowledge shared by my techie friend. ST My Ambiophonics System with Virtual Concert Hall Ambience Link to comment
sandyk Posted October 23, 2019 Share Posted October 23, 2019 26 minutes ago, STC said: This was a poor attempt to copy what Krell used to do with their CD players. They used green led to absorb the stray laser light. Perhaps someone got the idea from there to come up with the green pen marker. Knowledge shared by my techie friend. Well that failed too, because later on they found that the application of the green pen actually resulted in increased Jitter, which many seem to like as it can sometimes sound a bit like added HF detail How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
mansr Posted October 23, 2019 Share Posted October 23, 2019 2 hours ago, STC said: This was a poor attempt to copy what Krell used to do with their CD players. They used green led to absorb the stray laser light. They did what now? Link to comment
STC Posted October 23, 2019 Author Share Posted October 23, 2019 4 minutes ago, mansr said: They did what now? Not seen any led lately. The other one was YBA. ST My Ambiophonics System with Virtual Concert Hall Ambience Link to comment
mansr Posted October 23, 2019 Share Posted October 23, 2019 19 minutes ago, STC said: Not seen any led lately. The other one was YBA. I mean, how is an LED supposed to absorb light? sandyk 1 Link to comment
STC Posted October 23, 2019 Author Share Posted October 23, 2019 29 minutes ago, mansr said: I mean, how is an LED supposed to absorb light? Just like how the green pen did? Still dont’t understand why green. And one used blue. CD laser is red. And they make these for believers. Faith cannot be questioned. ST My Ambiophonics System with Virtual Concert Hall Ambience Link to comment
mansr Posted October 23, 2019 Share Posted October 23, 2019 40 minutes ago, STC said: Just like how the green pen did? Still dont’t understand why green. And one used blue. CD laser is red. And they make these for believers. Faith cannot be questioned. Neither makes sense, but the LED makes even less sense. The green pen treatment was intended to stop scattered reflections of laser light escaping through the disc edge. If this really was a problem, at least treating it at the supposed source had some merit. Now how is an LED supposed to help with scattered light? Are they hoping the green case will absorb light of other wavelengths? Supposing it does, it's still not going to make any worthwhile difference. If you paint a square inch on a wall black, does the room get darker overall? Do they somehow believe that the green light will "neutralise" the red light from laser? Confused, perhaps, by some high-school chemistry experiment involving acids, bases, and a pH indicator? If stray light were a concern, painting the interior in Vantablack would fix it. sandyk 1 Link to comment
Ralf11 Posted October 23, 2019 Share Posted October 23, 2019 7 hours ago, mansr said: I mean, how is an LED supposed to absorb light? the (crazy) idea must have been to create interference patterns Link to comment
sandyk Posted October 23, 2019 Share Posted October 23, 2019 10 hours ago, STC said: Just like how the green pen did? Still dont’t understand why green. And one used blue. CD laser is red. And they make these for believers. Faith cannot be questioned. Incidentally, LEDs can not absorb light, but they can detect light like a photodiode, and also output a DC voltage as a response to light. You could even use a string of them in parallel and series to create a low power Solar Cell. https://www.techulator.com/resources/10515-LED-solar-cell-its-working.aspx How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
STC Posted October 25, 2019 Author Share Posted October 25, 2019 On 10/24/2019 at 5:26 AM, sandyk said: Incidentally, LEDs can not absorb light, but they can detect light like a photodiode, and also output a DC voltage as a response to light. You could even use a string of them in parallel and series to create a low power Solar Cell. https://www.techulator.com/resources/10515-LED-solar-cell-its-working.aspx These LEDs not connected to anything. They just lit up next to the laser shining the transport mechanism. I am only guessing that the green light mixes with stray red somehow makes them not to have any influence in the data picked up by the laser unit from the CD itself. Hopefully, another unit will come soon and I will do blind tests with the LEF on and Off. ST My Ambiophonics System with Virtual Concert Hall Ambience Link to comment
STC Posted October 25, 2019 Author Share Posted October 25, 2019 Testing the Sumo Athena preamp. IMG_2224.MP4 ST My Ambiophonics System with Virtual Concert Hall Ambience Link to comment
STC Posted October 25, 2019 Author Share Posted October 25, 2019 Coming soon. Group repair. ST My Ambiophonics System with Virtual Concert Hall Ambience Link to comment
mansr Posted October 25, 2019 Share Posted October 25, 2019 9 hours ago, STC said: These LEDs not connected to anything. They just lit up next to the laser shining the transport mechanism. I am only guessing that the green light mixes with stray red somehow makes them not to have any influence in the data picked up by the laser unit from the CD itself. That isn't how light works. As for CD pickups in general, the photodetector is likely most sensitivite around the wavelength of the laser and relative insensitive to green light. Moreover, due to the construction of the optics, only light from a small angle reaches the detector in the first place. Link to comment
botrytis Posted October 25, 2019 Share Posted October 25, 2019 Photodetectors are usually not keyed to specific wavelengths, they can pick up any wavelength. It is more to do with the small angle as you said, mansr. Current: Daphile on an AMD A10-9500 with 16 GB RAM DAC - TEAC UD-501 DAC Pre-amp - Rotel RC-1590 Amplification - Benchmark AHB2 amplifier Speakers - Revel M126Be with 2 REL 7/ti subwoofers Cables - Tara Labs RSC Reference and Blue Jean Cable Balanced Interconnects Link to comment
mansr Posted October 25, 2019 Share Posted October 25, 2019 1 minute ago, botrytis said: Photodetectors are usually not keyed to specific wavelengths, they can pick up any wavelength. It is more to do with the small angle as you said, mansr. The datasheets say otherwise. Here's the sensitivity of a random photodiode from Vishay: A CD laser has a wavelength of 780 nm, close to the sensitivity peak of this photodiode. For green light of 550 nm, it is only half as sensitive. Contrast that with this one: Link to comment
Popular Post The Computer Audiophile Posted October 25, 2019 Popular Post Share Posted October 25, 2019 Nerds 😁 Kyhl, Teresa and Ralf11 3 Founder of Audiophile Style | My Audio Systems Link to comment
Ralf11 Posted October 25, 2019 Share Posted October 25, 2019 Here is how light works: RickyV 1 Link to comment
Ralf11 Posted October 25, 2019 Share Posted October 25, 2019 exceptions apply in or near a Black Hole Link to comment
Allan F Posted October 25, 2019 Share Posted October 25, 2019 On 10/23/2019 at 1:13 AM, sandyk said: Well that failed too, because later on they found that the application of the green pen actually resulted in increased Jitter, which many seem to like as it can sometimes sound a bit like added HF detail If i recall correctly, it was Keith Johnson who discovered this effect. "Relax, it's only hi-fi. There's never been a hi-fi emergency." - Roy Hall "Not everything that can be counted counts, and not everything that counts can be counted." - William Bruce Cameron Link to comment
RickyV Posted October 25, 2019 Share Posted October 25, 2019 21 minutes ago, The Computer Audiophile said: Nerds 😁 What kind of nerds?, electronic nerds, physic nerds, “scientist” nerds, audio nerds, audiophile nerds, OCD nerds, audio forum nerds, not really audiophile nerds but have nothing better to do. All kinds of nerds here. 😇 The Computer Audiophile 1 Meitner ma1 v2 dac, Sovereign preamp and power amp, DIY speakers, scan speak illuminator. Raal Requisite VM-1a -> SR-1a with Accurate Sound convolution. Under development: NUC7i7dnbe, Euphony Stylus, Qobuz. Modded Buffalo-fiber-EtherRegen, DC3- Isoregen, Lush^2 Link to comment
sandyk Posted October 25, 2019 Share Posted October 25, 2019 2 hours ago, Allan F said: If i recall correctly, it was Keith Johnson who discovered this effect. Hi Allan You have a pretty good memory . Kind regards Alex https://audiophilestyle.com/forums/topic/27888-painting-the-edge-of-a-cd-green/page/2/ How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
Allan F Posted October 25, 2019 Share Posted October 25, 2019 2 minutes ago, sandyk said: Hi Allan You have a pretty good memory . Kind regards Alex https://audiophilestyle.com/forums/topic/27888-painting-the-edge-of-a-cd-green/page/2/ Long term only, Alex. My short term memory sucks! Regards, Allan Jud 1 "Relax, it's only hi-fi. There's never been a hi-fi emergency." - Roy Hall "Not everything that can be counted counts, and not everything that counts can be counted." - William Bruce Cameron Link to comment
sandyk Posted October 25, 2019 Share Posted October 25, 2019 40 minutes ago, Allan F said: Long term only, Alex. My short term memory sucks! Regards, Allan Hi Allan That's par for the course as you age. I have found recently that I have occasional trouble recalling the names of actresses and actors from recent times, but sometimes the next time I see them, their name pops into my head without consciously thinking about it. I will send you a copy of a reassuring email. Kind Regards Alex How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
botrytis Posted October 25, 2019 Share Posted October 25, 2019 There ya go...... Current: Daphile on an AMD A10-9500 with 16 GB RAM DAC - TEAC UD-501 DAC Pre-amp - Rotel RC-1590 Amplification - Benchmark AHB2 amplifier Speakers - Revel M126Be with 2 REL 7/ti subwoofers Cables - Tara Labs RSC Reference and Blue Jean Cable Balanced Interconnects Link to comment
mansr Posted October 25, 2019 Share Posted October 25, 2019 58 minutes ago, sandyk said: Hi Allan You have a pretty good memory . Kind regards Alex https://audiophilestyle.com/forums/topic/27888-painting-the-edge-of-a-cd-green/page/2/ Three years later, we still have no information at all about what Keith Johnson actually measured, much less a replication of his experiment. Link to comment
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