I am having trouble understanding how cavity resonance is relevant for a device that woks by quantum mechanical principles.
Actually I asked Santa if he wouldn't mind. He's a big audio fan.
Stuart, first things first. Picture of the little darlings please. We know the Camera Lady can make them look good.
Stuart, first things first. Picture of the little darlings please. We know the Camera Lady can make them look good.
If you have quantized shizzle, quantity matters. The beauty of cavities is the enhancement or suppression of modes. Look at Fabry-Perot interferometers, laser cavities and linewidth, or cavity-qed in general (lol, maybe don't, it takes a decade). A cavity gives boundary conditions to the wavefunction, and therefore gives restraints it to possible solutions/outcomes.
That is all. (Like in japanese fairytales.)
Things with wires don't even get questioned since Sherri once worked for Motorola. We both worked in the calibration lab. Actually that's where we met. She even ordered a lot of HP (High Price) test equipment. She remarked once that she ordered a spectrum analyzer that cost more than we paid for out house! What gets her attention is the prices that some tubes fetch! "You mean somebody paid you $350 for those dirty old tubes!" I sold some used but tested WE 367A's on Ebay. I bought a Volvo station wagon full of old "electric things" from an antique dealer in rural Florida for $100. The first box fetched my $100 back on Ebay. The NOS twist lock electrolytics sent the entire orient into overbid even though I explained that they had been sitting in the Florida heat for 50 years!
The amp was a Tubelab SE that I hacked up for a customer who had plenty of money and wanted something special. The guy lived next door to my brother in a gated golf course community. I heard him talking about the high end stereo he had bought in Hong Kong and asked to see it. He had paid over $5K for the 300B amp. He showed me his system and it was very nice looking and sounded good too. After the demo, I told him that I had tube amps too, and I made them myself. I told him I would bring one next time I came to Tampa.
I loaned him a Tubelab SE because he was looking for a bedroom system. When I went to get it back, it was in his main system in place of the $5K amp. Of course I made him one like it to fit in a custom cabinet that he had made. Later he called me and asked if I could make him an amp just for headphones.
He made two trips here (500 miles round trip) so he could audition several different designs with his headphones. The final design was a Tubelab SE running on a lower supply voltage so that it could use 01A's 30's or 31's for output tubes. We added a choke to the power supply. Which is a typical CLC with a polyprop added across the last electrolytic.
Some details here:
Headphone Amp
Granted my hearing sucks due to several bouts with Menieres Disease and far too many rock concerts in my younger days. Yes the amp is SE, and the difference could be as simple as a few volts of supply voltage change, but neither of us saw big differences on the variable power supply during the "voicing" of the amp. Yes, he was listening to some CD's that he brought and I was unfamiliar with.
It does, I have taken them apart. The 8640 uses a cavity with a movable wall to tune the main oscillator from 256 to 512 MHz. The lower frequencies are divided down from there. Some versions had a frequency doubler option for use up to 1024MHz. This generator had the best phase noise available in its day, and it still better than some of todays generators IF you han find one that still works. The plastic gears have crumbled, the output amplifiers and attenuators have failed. Replacement parts are no longer available.
They weren't too good. We plugged them in and never turned them off. They were stable enough to stay within a KHz or two at 850 MHz after being on for a week or so.
Just about any generator below 10 GHz uses a phase locked loop to generate the highest frequency range. The lower ranges are divided down, or mixed down from there. There are very few commercial signal generators available today that can be used to measure the IM and adjacent channel performance of our high end radios. The old HP 8644 and 8664 generators with the low noise option are the best ever made. Agilent doesn't make them any more and they aren't supported anymore either. Our department has purchased about 10 of them from the used equipment market in the past few years. Most of the new stuff is catered to the cell phone market. That is where the money is.
I don't need to Google. I haven't seen the devices, and I don't know the volume, but if they operate in the 15 to 30 GHz range (conveniently outside my measurement range) they would have virtually no effect on any reasonable electronics that wasn't constructed using special microwave devices and techniques. The wiring used in a HiFi system can't even cary signals in this range. Ordinary coaxial cable doesn't even work.
In the average residential environment there should be virtually NO RF energy in this range. There could be a tiny bit of third harmonic leakage from a wireless router or cordless phone (5.7 GHz) but the level will be very low. At the 15 to 30 GHz range ordinary building materials like plywood, sheetrock, and concrete block have serious attenuation so unless you have a cop pointing a K band radar unit (24.5 GHz) into your window there should be no microwave energy in this range in hour house.
Lets say that there is a K band transmitter right next to your amp, what could it do. Ordinary PVC wire insulation is very lossy, and makes an effective shield. Teflon will pass 15 GHz though. So, you have teflon interconnects with bad shielding (unlikely) that lets some of the 15 GHz energy inside the cable. The RCA connector will have about 30 db of loss at this frequency. OK, so there is a really powerful microwave source, so some gets in. How many amplifiers use a GaAs or GaN fet mounted on teflon PCB using microstrip techniques in the input stage that could actually see that energy.
Well we have discussed the Bybee Purifier, Quantum Mechanics, Superconductors, and Semiconductors. I know nothing about these things, so I say nothing.
I have been an audio enthusiast for 40+ years, and worked at Motorola for 37 years. During that time I spent a few years in the factory, then 10 years in the calibration lab, 15 years in product development (cell phones and two way radios), and the past 10 years in an advanced development lab working on stuff that might be state of the art in a few years.
So when it comes to RF, microwaves, and testing developing methods of test, I can speak! OK, I'll shut up now.
Right on about the iDEN phones. Those things are awful. We used to have to ban them from shows. And we all carried Nextel, so the 1st order of biz on the com was "Phones off, everyone!" Tic, tic, tic, Brrrrrurt! Don't know how they ever got past the FCC. (I actually asked once, and just got a knowing smile)
I was the lead RF engineer on a few of them.
When Nextel hadn't gone live in Florida yet, we had our own 3 site test system that we used for phone development. No one knew what they were. We would go into stores like Circuit City or Best Buy and create a racket. I was in Sam Ash music looking at guitars for my daughter when someone private called me. The guy cranking on a SUNN bass amp thought he had blown it up. I walked toward the door and even the Yamaha Digital Grand piano was going crazy.
I know, but I shouldn't say. I still work there.
Your Droid is probably on Verizon.
Verizon uses CDMA which causes the least interference of any "MA". CDMA (code division multiple access) uses a constant power level but spreads the information across a wide frequency range using a spreading code (spread spectrum). CDMA is a US based standard with most of the IP controlled by Qualcomm. It has gained acceptance in the orient and a few other places. It evolved from military covert communications work during WWII. There are several frequency allocations for CDMA. Most are in the 824 to 850 MHz and 1.8 to 2.1 GHZ range. There are some other allocations world wide.
GSM is a TDMA standard (time division multiple access) it uses tiny slices of time (time slots) to allow multiple users to access the same RF channel. This means that the transmitter is turned on only in the appropriate time slot which is a few mS wide. The repitition rate is about 50 Hz. The pulsing transmitter makes it very noticable in audio systems, and causes bit errors in digital systems. GSM is a world wide standard and is used in four frequency bands, two in the US. GSM transmit is at 824 to 850 and around 1.9 GHz in the US. 900 MHz and 1.8 GHz are common in Europe. There are some other allocations world wide.
iDEN is by far the worst case. It is a TDMA system but the repitition rate is slower 11 or 22 Hz depending on mode. This makes the interference more noticable. The DTX rate (in a call but not talking) is about 1 to 2 Hz (tic tic tic). All iDEN operation in the US transmits in the 806 to 824 MHZ range with the majority of the frequencies at 820 to 824. Nextel has a few licenses in the 896 to 901 MHz band but by agreement they are being phased out. Other frequencies are used in Japan.
Cordless phones, wireless routers and other unlicensed RF emitters are required to operate in a few fixed frequency ranges known as ISM bands. (Industrial Scientific Medical) Each band has specific power, range, and emission mode limitations. In the US (and most of the world) the most common are 902 to 928 MHz, 2.4 to 2.45 GHz and 5.7 GHz. there are others but the requirements are such that they arent used for much. Car and garage opener remotes are in the 200 to 400 MHz range but are restricted to very low power and short transmission times. These are the exact same frequencies that are used for secret military communications. The low power devices provide the "cover" for the secret stuff to hide in.
Verizon uses CDMA which causes the least interference of any "MA". CDMA (code division multiple access) uses a constant power level but spreads the information across a wide frequency range using a spreading code (spread spectrum). CDMA is a US based standard with most of the IP controlled by Qualcomm. It has gained acceptance in the orient and a few other places. It evolved from military covert communications work during WWII. There are several frequency allocations for CDMA. Most are in the 824 to 850 MHz and 1.8 to 2.1 GHZ range. There are some other allocations world wide.
GSM is a TDMA standard (time division multiple access) it uses tiny slices of time (time slots) to allow multiple users to access the same RF channel. This means that the transmitter is turned on only in the appropriate time slot which is a few mS wide. The repitition rate is about 50 Hz. The pulsing transmitter makes it very noticable in audio systems, and causes bit errors in digital systems. GSM is a world wide standard and is used in four frequency bands, two in the US. GSM transmit is at 824 to 850 and around 1.9 GHz in the US. 900 MHz and 1.8 GHz are common in Europe. There are some other allocations world wide.
iDEN is by far the worst case. It is a TDMA system but the repitition rate is slower 11 or 22 Hz depending on mode. This makes the interference more noticable. The DTX rate (in a call but not talking) is about 1 to 2 Hz (tic tic tic). All iDEN operation in the US transmits in the 806 to 824 MHZ range with the majority of the frequencies at 820 to 824. Nextel has a few licenses in the 896 to 901 MHz band but by agreement they are being phased out. Other frequencies are used in Japan.
Cordless phones, wireless routers and other unlicensed RF emitters are required to operate in a few fixed frequency ranges known as ISM bands. (Industrial Scientific Medical) Each band has specific power, range, and emission mode limitations. In the US (and most of the world) the most common are 902 to 928 MHz, 2.4 to 2.45 GHz and 5.7 GHz. there are others but the requirements are such that they arent used for much. Car and garage opener remotes are in the 200 to 400 MHz range but are restricted to very low power and short transmission times. These are the exact same frequencies that are used for secret military communications. The low power devices provide the "cover" for the secret stuff to hide in.
Yes, Verizon. I should be able to borrow a GSM phone.
I was surprised to find that the Bybee devices were encapsulated (including the leads) in a dip PVC (like the stuff you use to coat the handles of metal tools). I thought that was supposed to be a no-no material in high quality audio applications?
I was surprised to find that the Bybee devices were encapsulated (including the leads) in a dip PVC (like the stuff you use to coat the handles of metal tools). I thought that was supposed to be a no-no material in high quality audio applications?
We can thank Hedy Lamarr for that. (in part, anyway) Beauty and brains.
I doubt that even a Bybee could help with the iDEN bursts. They seems to get in everywhere.
As for PVC, I think Bud likes it OK as a dielectric. Bud, please chime in here.
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