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Post by leonski on Jul 4, 2022 23:55:29 GMT -5
In chemical processing, vacuum pumps are used to assist in the drying of powders. Good. We used 'em for many other reasons, but never for drying anything. Ever freeze stuff first and use sublimation pumping? Cheers: and a Happy 4th to you! I'm going outside now and light my firework. I still have a sparkler left....... |
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Post by Boomzilla on Jul 5, 2022 6:28:13 GMT -5
Since our daughter grew up and moved away, I don’t normally buy fireworks anymore. But my wife does like sparklers…. Next time I’ll get her a pack. Thanks for reminding me!
Boom
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Post by leonski on Jul 5, 2022 15:44:16 GMT -5
I also light a sparkler on Guy Fawkes Day. Remember, remember, the 5th of November.....
Poor schmuck was implicated in the Gunpowder Plot of the very early 1600s. And was later drawn and quartered....or some such....
I did a sublimation demo for my nephews many years ago. We were in Palm Desert and it was 110f. I took an ice cube outside and put it on
a dark manhole cover. It just disappeared in about a minute. Without melting first. It was like spending a week in a science fiction movie.
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Post by Boomzilla on Jul 5, 2022 15:59:10 GMT -5
Yes - I've done sublimation for my daughter using a block of CO2.
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Post by leonski on Jul 5, 2022 17:49:32 GMT -5
Yes - I've done sublimation for my daughter using a block of CO2. Excellent. good demo....... |
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Post by Boomzilla on Jul 19, 2022 8:40:52 GMT -5
Power distribution:
My current living/audio room has no dedicated circuits. Since I plan to sell the house soon, I'm not adding any. But I want clean power and maximum amperage to my equipment. So:
A long power strip will plug directly into the wall - no power conditioning - no surge suppression - no nothing. Into this strip, I'll plug:
The TV (high current draw but not on while listening to music)
Two Emotiva PA-1 power amplifiers + Crown PS-2 power amplifier + two Heathkit tube mono block amplifiers + a Black Ice F22 tube integrated amplifier (only one of these + items will be on at any time)
A surge suppressor
A UPS
Into the surge suppressor, I'll plug:
The Cable TV box
The Cable modem & wireless router
An Emotiva Stealth DC-1 DAC
An Emotiva PT1 preamplifier
A Schiit Loki equalizer
A DVDRW disc reader
Into the UPS, I'll plug:
A Mac mini computer
An external USB HDD
Why this specific lineup?
I want power amplifiers / integrated amplifiers to have unlimited current and I'm willing to rely on the internal power protection circuitry to protect the equipment
I want the low-current circuitry (like preamps & DACs) to have at least surge suppression upstream
I want the computer and external HDD to never lose power (lest I scramble data accidentally)
Anything I've missed?
Thanks - Boomzilla
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Post by leonski on Jul 19, 2022 14:39:57 GMT -5
Boom? I'd CONSIDER a high power Isolation Transformer. For you? 1KvA should be OK.....
And when you settle in the 'new digs', I'd of course consider a whole-house surge protection scheme. Either MOV (cheap but may need to be replaced)
or one of the other types, which are 'lightning' fast and have few or no limits........Memory fails on name or detail...
I have a 400va Iso and plug in TV, small dish box and my preamp. All 3 together are way under capacity.
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KeithL
Administrator 
Posts: 10,255
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Post by KeithL on Jul 20, 2022 9:29:18 GMT -5
An isolation transformer will NOT specifically give you surge protection... although some units do add some surge suppression. For a non-sacrificial surge suppressor you need a series-mode type - from someone like BrickWall or SurgeX ... (Brickwall makes mostly single-circuit units; SurgeX makes both small and large units.) These also add quite a bit of RF noise filtering (so do isolation transformers). Boom? I'd CONSIDER a high power Isolation Transformer. For you? 1KvA should be OK..... And when you settle in the 'new digs', I'd of course consider a whole-house surge protection scheme. Either MOV (cheap but may need to be replaced) or one of the other types, which are 'lightning' fast and have few or no limits........Memory fails on name or detail... I have a 400va Iso and plug in TV, small dish box and my preamp. All 3 together are way under capacity. |
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Post by leonski on Jul 20, 2022 14:29:48 GMT -5
That is specifically WHY I have an ISO trans. Much if not all RF hash is eliminated. That and a whole-house surge system?
It is EASY to DIY an Iso Trans with MOV protection at the input AND at each outlet.....though I don't know the effectiveness of the last.
I don't know that Panamax makes anything like what I have now. It was $$$ when I bought it, but also has is a near-lifetime piece.
Trouble? Well, yes. A large ISO Trans is heavy. Even my 400va type in my Power conditioner is pretty dense.
An 1800 watt TripLite Medical Grade with 6 outlets weighs nearly 60lb, shipping......
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KeithL
Administrator
Posts: 10,255
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Post by KeithL on Jul 20, 2022 16:41:49 GMT -5
The effectiveness of MOVs depends to a large degree on the circumstances where you happen to be located. NOTHING will protect you from a direct lightning strike. (A lightning rod can do so because it takes the strike instead of your electrical system.) In a normal "power surge" lightning has hit the power grid somewhere upstream. The massive arrestors in the power grid have hopefully shunted most of the resulting current to ground. What's left is a VOLTAGE surge going through the system.. which can reach up to several thousand volts. (And there can be quite a bit of current behind this voltage surge.) MOVs work by shunting current to ground. This works because the transformer on the pole, and the wiring itself, has resistance. Therefore, if you can shunt ENOUGH current to ground, the voltage drop in the transformer and the wiring will "drop" most of the voltage. And what gets through will be little enough that your gear won't be damaged. Likewise, an MOV at the individual outlet will eventually short enough current to ground to pop your circuit breaker. This adds another level of protection. (Unfortunately circuit breakers are FAR too slow to protect equipment from a surge... There are two main "catches" with MOVs. The first is that, in order to do their job, they MUST be able to shunt most of the current behind the surge to ground. So, if there's too much current involved, the MOVs may simply pop, and allow most of the surge to get through. A typical home MOV surge suppressor will be rated in hundreds of joules (or maybe low thousands)... and a typical lightning strike is between 1 and 10 BILLION joules. (Luckily, in most cases, what we call "a surge" is really just a minor surge in the grid voltage caused by a distant lightning strike.) The other catch is that MOVs degrade after repeated hits. For one thing they may eventually simply stop working. However, in many cases, they will end up shorting, or engaging prematurely, and sort of self-destructing. (This won't hurt your gear, but it may pop a circuit breaker, of make some stinky smoke.) MOST good quality MOV-type surge suppressors have some sort of indicator when they've failed or "are starting to wear out". A series-mode surge suppressor works by blocking the voltage surge from entering your home circuitry. This means that they do NOT have to shunt a huge amount of current to ground... Rather than shunt the current to ground they simply block it rather than absorb it... which keeps the voltage inside from rising. This makes them a better proposition in areas that are either prone to BIG surges... where they offer better protection... Or in areas where you are likely to get A LOT of surges... because they don't wear down or fail over time and repeated surges. The down-side is that series-mode surge suppressors tend to be rather larger and more expensive. They DO, however, include a large inductor, which gives them the same RF-filtering properties as an isolation transformer. (But they do not provide ground isolation.) MOVs tend to be commonly used for two reasons... 1. They work reasonably well for their intended purpose... 2. They are REALLY CHEAP for a given level of performance... That is specifically WHY I have an ISO trans. Much if not all RF hash is eliminated. That and a whole-house surge system? It is EASY to DIY an Iso Trans with MOV protection at the input AND at each outlet.....though I don't know the effectiveness of the last. I don't know that Panamax makes anything like what I have now. It was $$$ when I bought it, but also has is a near-lifetime piece. Trouble? Well, yes. A large ISO Trans is heavy. Even my 400va type in my Power conditioner is pretty dense. An 1800 watt TripLite Medical Grade with 6 outlets weighs nearly 60lb, shipping...... |
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Post by Boomzilla on Jul 20, 2022 16:56:42 GMT -5
Story from one of the plant electricians who did home wiring on the weekends...
He was wiring a light fixture in a house with the main breaker disconnected on a stormy day. Saw lightning strike in the distance through a window and simultaneously a spark came out of the light fixture and knocked him off his ladder.
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Post by leonski on Jul 20, 2022 22:59:38 GMT -5
Story from one of the plant electricians who did home wiring on the weekends... He was wiring a light fixture in a house with the main breaker disconnected on a stormy day. Saw lightning strike in the distance through a window and simultaneously a spark came out of the light fixture and knocked him off his ladder. I was in Palm Springs when a SUMMER storm blew thru. Like over an inch of rain in 2 hours. 3 lightning strikes within 'butt pucker' distance....and the bright flash, as well. Only damage? Dial Up Modem on one of the computers......LUCKY... Everyone OUT of the pool! www.mouser.com/pdfdocs/bourns-tips-on-selecting-the-right-mov-surge-suppressor-white-paper.pdfMouser white paper concerning the MOV device.......very interesting..... |
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Post by leonski on Jul 20, 2022 23:00:57 GMT -5
Keith?
How come MOVs are rated in volts? (as well as an energy product.....Joules)?
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Post by Boomzilla on Jul 21, 2022 5:34:59 GMT -5
Something I didn't know previously: Equipment that accepts a USB 3.0 Type B plug: can also be used with a USB 2.0 Type B plug: You'll get the slower 480 Mbps transfer rate if you use the Type 2.0 cable, but it will still work, and either one will be sufficient for music. Just a FYI... |
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Post by garbulky on Jul 21, 2022 5:52:12 GMT -5
What kind of equipment do you use that accepts the 3 type B out of curiosity?
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Post by Boomzilla on Jul 21, 2022 7:45:25 GMT -5
Every USB HDD cradle that I own uses the USB-3 Type B connector. I also have a RAID that uses the same connector.
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Post by Boomzilla on Jul 21, 2022 8:04:13 GMT -5
Strange story on a green-room topic...
The other day I ran my gasoline powered Generac generator for maintenance purposes. When I went out to shut it down, it had already died. My first thought was that it had run out of gas, so I removed the gas cap to look, and as I did, I discovered that the tank was pressurized! Looking into the tank, I found that I still had plenty of gas, but that the gas was boiling like a pot of water on the stove, and a continued flow of vapor coming out of the tank prevented me from putting the cap back on.
On consulting the neighborhood small engine expert, he told me that such gas tank caps are frequently vented, and that ants or spiders have a tendency to plug the small vent holes. When the tank can no longer vent, the motor (located below the gas tank) heats the tank contents and causes pressure to build up. In cases where the engine does not heat the tank, a vacuum can occur in the tank as liquid level flows to the engine without an air makeup for the lost liquid volume in the tank.
Once higher pressure occurs (as in my case) the liquid and vapor space reach equilibrium with some of the compressed vapor in the tank being dissolved into the liquid. When the pressure is suddenly reduced (as when I removed the cap), the vapor "boils" out of the liquid until equilibrium is achieved at the new lower (atmospheric) pressure.
The generator had stopped because the high pressure gas flowing into the carb made the intake mixture too rich, and the motor shut down because the mixture was too rich to burn.
So I removed the gas cap, disassembled it, and found, to my surprise, that the cap was not intended to be vented, and had a rubber gasket that sealed against the tank tightly. Further inspection revealed that the tank had a vent tubing on top that was routed to the carb intake downstream of the air filter. I pulled the tubing off and found that I could easily blow through into the carb intake, but when I tried to blow back into the gas tank, no flow was possible.
The tubing fitting atop the tank consisted of two parts; a snap-in housing that connected directly to the tank and a swiveling tubing connection that could rotate in the snap-in housing. There is an arrow on the snap-in housing (but no indication on the tank of where the correct position might be). Experimentation showed that if (and only if) the tubing connection was exactly at 180 degrees opposite the arrow on the snap-in housing, venting could occur. If the tubing connection was even a few degrees away from the 180 degree position, the tank was sealed and no venting was possible.
Since the tubing orientation can easily be displaced while adding gas to the tank, this design is the very definition of "bad engineering." There is no reason why the generator would ever be operated without the tank vent open, and therefore the tubing connector should have been molded as part of the snap-in housing to avoid accidental closure. Live and learn...
Boomzilla
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Post by Boomzilla on Jul 21, 2022 10:08:06 GMT -5
Waiting for the end-of-the-year sale at the KEF online store. I'm thinking that I might exchange my Klipsch RP-600m speakers for some KEF LS-50 Meta ones. Will see how I feel about it come December... |
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hemster
Global Moderator
Particle Manufacturer
...still listening... still watching
Posts: 51,950
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Post by hemster on Jul 21, 2022 11:56:25 GMT -5
Waiting for the end-of-the-year sale at the KEF online store. I'm thinking that I might exchange my Klipsch RP-600m speakers for some KEF LS-50 Meta ones. Will see how I feel about it come December... I have auditioned the KEF Meta and I found the sound interesting! Different, not worse/better than conventional speaker arrangement (tweeter atop the woofer). With concentric arrangement, it was very palatable, so no degradation but then, no perceptible improvement in SQ either. They do look cool though and have a lovely finish. Now, YMMV because the horn vs. concentric placed tweeter... should be interesting! |
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Post by Boomzilla on Jul 21, 2022 13:25:27 GMT -5
I'm hoping that a powerful amp with LOTS of current will make the KEFs as dynamic at low volumes as the Klipsches. Maybe - But maybe not...
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