Watching an old 1943 Westinghouse youtube video on how tubes work, I discovered that there are tubes that can transform light into electrical current.
A quick wiki leads us to photomultiplier tubes.
My point here is that we already have a way to convert digital signals to light and transmit them- TOSLINK.
So I present my stupid idea: TOSLINK -> Photomultiplier tube-> DAC output.
In essence this is an unliminited bit-perfect multibit DAC with no filtering of anykind.
Can this be done DIY? Probably not, but maybe. I'm hoping someone with far more resources and money picks this idea up and produces it. Honestly I don't care to profit off the idea if it does work, I just want to see it 😛
A quick wiki leads us to photomultiplier tubes.
"Photomultiplier tubes (photomultipliers or PMTs for short), members of the class of vacuum tubes, and more specifically vacuum phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. These detectors multiply the current produced by incident light by as much as 100 million times (i.e., 160 dB), in multiple dynode stages, enabling (for example) individual photons to be detected when the incident flux of light is very low. Unlike most vacuum tubes, they are not obsolete." - Wikipedia
My point here is that we already have a way to convert digital signals to light and transmit them- TOSLINK.
So I present my stupid idea: TOSLINK -> Photomultiplier tube-> DAC output.
In essence this is an unliminited bit-perfect multibit DAC with no filtering of anykind.
Can this be done DIY? Probably not, but maybe. I'm hoping someone with far more resources and money picks this idea up and produces it. Honestly I don't care to profit off the idea if it does work, I just want to see it 😛
Nice idea, but ... 🙄
What you would achieve was an amplified optical signal, still being digital. From there to analog would still require a DAC.
https://en.wikipedia.org/wiki/S/PDIF
What you would achieve was an amplified optical signal, still being digital. From there to analog would still require a DAC.
https://en.wikipedia.org/wiki/S/PDIF
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In essence, the photomultiplier would do exactly the same job as the photodiode in a TOSLINK receiver. No more, no less. Maybe you need to read about TOSLINK and SPDIF signal formats?
You have several major misconceptions, PMT's are far from noiseless or "bit perfect" and the TOSLINK signal is not an analog one that would benefit from some different kind of amplification.
I had a very nice stash of PMT's 15 years ago and was fortunate to unload them. Learned a lot about capacitors and shotgun shells.
Funny this Photo-multiplier tube was bought up, we used to use them with our very expensive color- analyser's we made for dark rooms back in the 70-80's.
I almost tried these tubes as a very complex form of Lightspeed Attenuator prototype before settling on the photo cells from junked Nikon camera light meters, with neon lamps before LED's
Cheers George
I almost tried these tubes as a very complex form of Lightspeed Attenuator prototype before settling on the photo cells from junked Nikon camera light meters, with neon lamps before LED's
Cheers George
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Hmm - with some dsp work, you migh be able to use the toslink sender to provide a pwm light signal, that you could run through the pmt.
I think you'd have a hard time to make it linear, but that can also be fixed in the dsp.
Maybe not worth the effort sound quality wise, but a totally cool project.
Johan-Kr
I think you'd have a hard time to make it linear, but that can also be fixed in the dsp.
Maybe not worth the effort sound quality wise, but a totally cool project.
Johan-Kr
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