Sorry, my comment did not come out right - I apologize.
Anyway, we are of a similar age.
I really had no problem with your comment and considered it a good joke
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I was always under the impression that when a circuit is broken, inductance raises the voltage to whatever it takes to keep the current flowing. Obviously when those contactors open, the current "wants" to keep flowing. So what voltage level does it hit just before it "gives up" and the arc extinguishes?
One would think DIY AC "line regeneration" wouldnt be all that difficult - particularly if considered as part of the amplifier power supply - discarding of course all the 60 Hz AC parts. HP level induction motor; obtanium. Car "alternator"; obtainium. Pulleys and belts; obtanium. Regulator design to make just about whatever isolated DC voltage value you want; obtainium.
I bet the ripple frequency from a 3 phase car alternator spinning at what, 6K RPM is a lot easier to deal with bulk cap wise than 120Hz...
One would think DIY AC "line regeneration" wouldnt be all that difficult - particularly if considered as part of the amplifier power supply - discarding of course all the 60 Hz AC parts. HP level induction motor; obtanium. Car "alternator"; obtainium. Pulleys and belts; obtanium. Regulator design to make just about whatever isolated DC voltage value you want; obtainium.
I bet the ripple frequency from a 3 phase car alternator spinning at what, 6K RPM is a lot easier to deal with bulk cap wise than 120Hz...
This leads me to think of line voltage as a factor. The line regenerator may (probably does, surely the output is regulated) put out a voltage different from the line. I'd go look if it says anything about input/output voltages, but I've read the PS Audio site before and I find it annoying.
One of the problems of making excellent line regenerators is: audiophiles connect audio power amplifiers to them!
Audio power amplifiers usually have a large power transformer, some rectifier diodes, and a capacitor bank.
To minimize voltage ripple on the DC power supplies, audiophile power amplifiers employ a LARGE capacitor bank having many many microfarads of capacitance.
UNfortunately, with large capacitance and low ripple, the power transformer and the rectifiers must supply ALL of the necessary coulombs of electrical charge, in a very brief & very narrow pulse. Some books talk about the narrowness of this current pulse using the terminology "conduction angle".
To supply the necessary load current in a narrower and narrower pulse of current, you gotta make that pulse taller and taller. Where do these super tall current pulses come from? From the rectifiers, and from the power transformer secondary. Which means there are identical current pulses (multiplied by the transformer turns-ratio) flowing in the transformer primary. Which means there are identical current pulses sucked out of the line regenerator. Fifty or a hundred amps tall. Ouch!!
Hook up an enormous macho power amplifier with 200,000 microfarads of filter capacitance, to a line regenerator, and then play it at maximum volume. It's a torture test of the regenerator.
Audio power amplifiers usually have a large power transformer, some rectifier diodes, and a capacitor bank.
To minimize voltage ripple on the DC power supplies, audiophile power amplifiers employ a LARGE capacitor bank having many many microfarads of capacitance.
UNfortunately, with large capacitance and low ripple, the power transformer and the rectifiers must supply ALL of the necessary coulombs of electrical charge, in a very brief & very narrow pulse. Some books talk about the narrowness of this current pulse using the terminology "conduction angle".
To supply the necessary load current in a narrower and narrower pulse of current, you gotta make that pulse taller and taller. Where do these super tall current pulses come from? From the rectifiers, and from the power transformer secondary. Which means there are identical current pulses (multiplied by the transformer turns-ratio) flowing in the transformer primary. Which means there are identical current pulses sucked out of the line regenerator. Fifty or a hundred amps tall. Ouch!!
Hook up an enormous macho power amplifier with 200,000 microfarads of filter capacitance, to a line regenerator, and then play it at maximum volume. It's a torture test of the regenerator.
Mark,
Regenerators often offer a higher frequency typically 75 hertz or so. They also will have rail voltages high enough to allow some sag in their storage capacitors to allow some drop before it affects the output voltage. So the issue is more does it have the current capacity just at peak voltage. I did a version where I used an isolation transformer in series with a low voltage very high current boost/buck amplifier.
The other trick is that the output peak voltage does need to be typically 170 volts, but unlike a true sinewave it can have a flatter top to allow the load capacitors more time to charge. A typical spec calls for less than .5% distortion. That actually allows you to increase the peak charge time and still keep the total waveform distortion low.
Regenerators often offer a higher frequency typically 75 hertz or so. They also will have rail voltages high enough to allow some sag in their storage capacitors to allow some drop before it affects the output voltage. So the issue is more does it have the current capacity just at peak voltage. I did a version where I used an isolation transformer in series with a low voltage very high current boost/buck amplifier.
The other trick is that the output peak voltage does need to be typically 170 volts, but unlike a true sinewave it can have a flatter top to allow the load capacitors more time to charge. A typical spec calls for less than .5% distortion. That actually allows you to increase the peak charge time and still keep the total waveform distortion low.
Yes Ed, PS Audio includes the flattop waveform technology in their $8000 mains regenerator products. They call it Multiwave and they give the user a knob to frobbulate, which controls the flatness % of the halfsine. More importantly they give the user >>CONTROL<< . Bwaaahha ha haah, now the user can tweak to her/his heart's content.
Here's their writeup (.pdf attached)
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Here's their writeup (.pdf attached)
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What do you think about electric current in a conductor? On the one hand, the signal is transmitted at a speed close to the speed of light, or tends to this speed. On the other hand, electrons in metals move extremely slowly. I wonder how fast the electrons move in the arc. By the way, in Russia there are high-speed switches on pyrapatrons.
Arkana Research
My friend has a whole collection of these interesting audio cables. And I am familiar with the owner of this company. He is originally from Russia.
I will take a pass on it as well. I have been specifying isolation transformers for broadcast and recording studio use for over 30 years. I used to install many Topaz transformers, and although they had undersized cores, ran hot as fire, had less than excellent voltage regulation and often buzzed which made them less than desirable for studio use, there wasn't anything better on the market...then in the late 1990s Topaz went out of business.
I tried the Deltec and another brand I cannot remember now, but they were even worse for heat and noise. I specified a popular brand of balanced toroid transformers, but they make inferior isolation transformers due to the unavoidable proximity of the windings and shields which causes more capacitive coupling between shields. Plus they were expensive as heck, and I no longer install balanced power systems, with commonly available audio gear it causes more expense and problems than it solves.
The thing about shielding which Topaz and others don't elaborate on (because it looks bad) is the capacitance between shields. They just spec the primary to secondary winding capacitance, and the capacitance spec is measured by extremely low impedance perfect grounding of the interstitial shield, and no connection to the primary or secondary. In reality the shields form a capacitive voltage divider and any inductance (read: length of wire) in the interstitial shield connection raises it's impedance above ground, allowing primary shield noise voltage relative to ground to modulate it. From there it's capacitance to the secondary shield induces noise into it as well. In order to actually get good primary to secondary isolation from the Topaz I had to drive holes through concrete pads right next to them and drive ground rods which were kept wet by dripping water through the hole along side the rod.
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Over the last few years I have teamed up with a transformer design engineer with 50 years of experience and we have come up with a new design based on his micro-lamination staggered core designs. It has really excellent primary to secondary isolation and when the shields are properly grounded it has <5 pF primary to secondary winding capacitance. Even better thanks to the core design it is dead quiet other than an extremely small amount of magnetostriction at high powers, but still under an NC10 level. The core is ~50% larger in any given KVA rating than the Topaz and runs much cooler. We have installed quite a few of them from 5 KVA to 50 KVA and they can even be installed on the concrete pad immediately outside acoustic spaces with no audible vibration or buzzing, and unlike others there is no need to cut the pad around the transformer to reduce floor-borne vibration. Plus, despite being custom made to order they cost less than the boutique isolation transformers. We often combine them with Tempest Black grade AC line filters in commercial districts.
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That's my story and I'm sticking with it! (Until something better performing comes along...) I like the Dynamotor approach, it was used a lot in the 1920s-1960s before inverter technology caught up, and especially when only DC was available. Connected to a flywheel it could even offer some short-term voltage and frequency regulation. However, 5-50 KVA Dynamotor sets would be kind of big and expensive these days!
Cheers!
Howie
Today I decided to go simple for my music. In lockdown it's been almost impossible to listen to music whilst working due to the evils of messaging software and too many conference calls in the day, but today had some clean gaps so dug out my 'commuter system' of Sansa Clip and Etymotic ER4s. Very happy to see the clip had held most of its charge whilst sitting in a drawer for at least 14 months so fired it up and and enjoyed some music. The isolation of the ER4 is spooky after a gap in use but the combo works superbly, almost too well for the money.
Bill, I had that same setup & enjoyed it for many years, until my ER4s were stolen. Even lost the Clip down the car seat for most of a year, and it started right up as well. I have a handful of the Clip Zips now running the Rockbox firmware - use one or more of them every day. One for music, another for audiobooks - handy little gizmos.
I haven't found any headphones that can quite match that ER4 sound; I should just stop being cheap and buy another pair.
I haven't found any headphones that can quite match that ER4 sound; I should just stop being cheap and buy another pair.
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Guys, a few years ago I accidentally saw on the Internet a photo of a transformer distribution substation located in the United States, and judging by the black-and-white photo and clothes of people, it was 60-80 years old. So, this substation had three-phase toroidal transformers with a diameter of about 3 meters, judging by the height of the people in the picture. Maybe someone will find these photos, I recently tried but could not find them a second time.
There is a worldwide trend towards amorphous core distribution transformers. Because they consume very little no-load current and therefore power.
There is a worldwide trend towards amorphous core distribution transformers. Because they consume very little no-load current and therefore power.
Mine is with Rockbox as well. Makes it so much more usable.
I think I spent 15 years procrastinating over buying my ER4s. The funny thing was they used to be one of the most expensive IEMs around, now they seen quite cheap.
Next procrastination is getting some proper ear moulds made for them...
I think I spent 15 years procrastinating over buying my ER4s. The funny thing was they used to be one of the most expensive IEMs around, now they seen quite cheap.
Next procrastination is getting some proper ear moulds made for them...
Too bad in ear things are just are not going to happen here, I'll stick with my HD650's. My laptop's audio jack broke so I had to get an HDMI audio extractor with built-in DAC, sounds fine to me. I can't deal with fussing with a new computer right now.
Dynamotors are not history: Clean Power Concept: Flywheel Power Quality and Energy Storage | Kinectic Traction Systems - Clean. Power. Energy. They are a really good if expensive and potentially noisy solution. In the 1960's and 1970's a motor generator was essential for a computer installation. it was reliable simple and could easily ride through any momentary interruption. Also could allow switching to 400 Hz power so the power transformers can get smaller.
I remember reading about a Japanese Audiophile who has a Detroit Diesel generator set just for his audio. The obsession never ends.
Multiwave is interesting but this does what that promises and better: US5251120A - Harmonic noise isolation and power factor correction network
- Google Patents I have built them and they are really good, just difficult to get good power inductors. It does a great job of extending the conduction angle without creating harmonics back on the power line. The stress on rectifiers is much reduced.
The Monster AVS2000 voltage regulator was a lesson in how difficult power concepts can be to explain. I designed it to regulate against the peak of the AC since that's what an AV power supply runs on but I would get calls that "the voltage is off and the meter on the front is off per my Fluke TRMS meter". A 1/2 hour conversation would generally ensue with explanations of difficult concepts..
I remember reading about a Japanese Audiophile who has a Detroit Diesel generator set just for his audio. The obsession never ends.
Multiwave is interesting but this does what that promises and better: US5251120A - Harmonic noise isolation and power factor correction network
- Google Patents I have built them and they are really good, just difficult to get good power inductors. It does a great job of extending the conduction angle without creating harmonics back on the power line. The stress on rectifiers is much reduced.
The Monster AVS2000 voltage regulator was a lesson in how difficult power concepts can be to explain. I designed it to regulate against the peak of the AC since that's what an AV power supply runs on but I would get calls that "the voltage is off and the meter on the front is off per my Fluke TRMS meter". A 1/2 hour conversation would generally ensue with explanations of difficult concepts..
The problem with motor-generators is the they do not produce a clean sine wave! For some strange reason there is a need to have slots in the magnetic cores to allow inserting the coil wire. This gap in the magnetic structure results in distortion.
My small backup system runs above 5% distortion.
My small backup system runs above 5% distortion.
I'm with you on this. I don't like the feeling of IEMs, especially those that have high isolation.
I get a lot of use out of Apple AirPods for phone calls and podcasts for this reason, because they don't seal and sit outside your ear canal.
And then why do you need a clean sine wave? You aren't spinning a motor with your backup are you? Even motors today tend to be brushless DC types which are not connected to the line. As long as the higher harmonics are not too strong the transformers won't be stressed. Its all the rectifiers on the power line that give the 3% to 5% HD flattened sine wave usually seen on domestic power distribution.