sci.electronics.repair@googlegroups.com

Google Groups

vjp2.at@at.BioStrategist.dot.dot.com: Dec 08 02:38PM This video is perfect, except I'm worried I may not have room to strip. But I can strip with a razor blade.   I got scotch lock (the traditional twist connectors, which I sometimes tape to stabilise - and I have used since I was a toddler) and "chocolate bars" (the plug in crimps) confused. I am also curious about straight thru crimps, which may be the best for this job. I don't remember these things, am I right 12 guage will do?   I was a toddler when my mom's brothers were studying electrical engineering, just before we all moved into this house in 1965. So I have a feel for these things, just that I don't do it often enough and I need to be more careful because I live here. The wirings is therefore 1965. Hey, I've seen worse: I was part of a committee that chose computers for a hundred year old building in the 1980s and we needed UPS because everything was blowing.   Thanks to all   In <ovmjjv$jjt$1@dont-email.me> by Taxed and Spent <nospamplease@nonospam.com> on Wed, 29 Nov 2017 10:26:59 we perused: *+-On 11/27/2017 1:45 PM, vjp2.at@at.BioStrategist.dot.dot.com wrote: *+-> I got a switch that needs replacing but I'm afraid because the last time I *+-> replaced it the wires were old and the tips broke and i had almost no wire to *+-> use. An electrician chum told me about scothclock and I got two spools of *+-> wire (I didn't last time) but I'd like to see some videos to build up my *+-> confidence. BION last time I was so lost, it was late at night and I prayed *+-> for half an hour before I got it to work. Much obliged *+->     *+-https://www.youtube.com/watch?v=gmDj6i4pGDQ     - = - Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus blog: panix.com/~vjp2/ruminatn.htm - = - web: panix.com/~vjp2/vasos.htm facebook.com/vasjpan2 - linkedin.com/in/vasjpan02 - biostrategist.com ---{Nothing herein constitutes advice. Everything fully disclaimed.}---

"pfjw@aol.com" <pfjw@aol.com>: Dec 08 08:17AM -0800 > This video is perfect, except I'm worried I may not have room to strip. > But I can strip with a razor blade.   https://www.amazon.com/Ginsco-Terminals-Self-stripping-Insulated-Disconnects/dp/B01CDWC60Y   There are these. Would not be my first choice, but might get you out of trouble.   Peter Wieck Melrose Park, PA

whit3rd <whit3rd@gmail.com>: Dec 07 09:28AM -0800 > Now, I'm afraid to shut it off.   > What cause dit to "die" in the first place > was I hadn't used it in a long while   Yes, one sees this a lot on the (Apple II type) early switchmode supplies. The startup sequencing is critically dependent on some part of the (presumably) capacitor impedance, and good but stale-on-the-shelf capacitors make the startup fail. You just hear tick...tick...   I've tried replacing the big output filter capacitors (usual culprits for high-ESR failure mode) with no success, it's presumably NOT those, but one of the 'minor' parts. And, in at least three cases, let it tick overnight, and the next morning it's working. Will work for years. Use and enjoy.

vjp2.at@at.BioStrategist.dot.dot.com: Dec 08 02:40PM I don't want to jinx myself, but it turns on every day since I left it on for a few hours (and it finally revived) on Sunday.     - = - Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus blog: panix.com/~vjp2/ruminatn.htm - = - web: panix.com/~vjp2/vasos.htm facebook.com/vasjpan2 - linkedin.com/in/vasjpan02 - biostrategist.com ---{Nothing herein constitutes advice. Everything fully disclaimed.}---

"Percival P. Cassidy" <Nobody@NotMyISP.net>: Dec 08 11:13AM -0500 > went on but couldn't find the hard drive. Evetually after about ten times it > did. It worked daily for about ten days. I didn't use it for about a month, > after which it refuses to turn on. So I'm GUESSING it's the power supply.   As with many other brands of off-the-shelf computers, the power supply may be non-standard in many different ways, including a non-standard physical format and non-standard wiring. Other parts may be non-standard as well.   That's why I build my own computers from standard parts.   Perce

oldschool@tubes.com: Dec 07 02:31PM -0600 I want to rig up a subwoofer, but I know that crossovers are expensive, and since I am running high powered commercial amps, I'd need a hefty setup. Then comes the need to combine the left and right channels without loosing stereo separation.   I decided to go another route, My power amp was 600W (RMS). stereo. I got a good deal on another amp that is also a stereo commercial amp, rated at 500W RMS. Both amps are bridgable. The plan is to run the outputs from my preamp into Y adaptors and feed the left and right channels to BOTH amps. One of these amps I'll bridge and use that to power a single subwoofer speaker.   However, I need a means to send only the bass to the amp that powers the Subwoofer. Is there any sort of crossover made that goes in the input of the power amps, after the preamp?   I have also thought about just putting an equalizer into the input of the amp that feeds the subwoofer and raise the low end of the frequency and cut the highs. I'm not sure if that will adaquately work or not. I'll probably try it, but I have not yet built my subwoofer cabinet.   Either way, I know that 1100 watts rms is more than enough for a home stereo...

Fred Smith <fredsmith@thejanitor.corp>: Dec 07 09:35PM > However, I need a means to send only the bass to the amp that powers the > Subwoofer. Is there any sort of crossover made that goes in the input of > the power amps, after the preamp?   Lookup "low pass filter."     > Either way, I know that 1100 watts rms is more than enough for a home > stereo...   I think they only had 1000W in total at Woodstock...

Clifford Heath <no.spam@please.net>: Dec 08 09:00AM +1100 On 08/12/17 08:35, Fred Smith wrote: >> However, I need a means to send only the bass to the amp that powers the >> Subwoofer. Is there any sort of crossover made that goes in the input of >> the power amps, after the preamp?   Commonly done, even in my son's old Altec computer speakers.   > I think they only had 1000W in total at Woodstock...   The advertising for Deep Purple's Australian tour around 1975 focussed on "the world's most powerful PA - 10,000W!". They always were more about quantity than quality.   Clifford Heath.

"pfjw@aol.com" <pfjw@aol.com>: Dec 07 02:07PM -0800 https://www.crutchfield.com/S-YMAiepyOWcl/p_069900063/F-MODS-200-Hz-low-pass.html   Come in quite a range. 200hz is one of many. You could do it all with passive filters.   Most sub-woofers are configured as pass-through devices. Feed the full signal to the SW, and the filtered signal from the SW to the rest of the drivers. If you have separate amps, similarly, but the output from the SW is filtered line-level.   Peter Wieck Melrose Park, PA

"pfjw@aol.com" <pfjw@aol.com>: Dec 07 02:10PM -0800 > Either way, I know that 1100 watts rms is more than enough for a home > stereo...   I can make my ears bleed with Maggie speakers and a 200-watt amp in the one system, and AR speakers and also a 200 watt amp in another.   The difference between 200A and 1,100A is only a bit over 5dB anyway, so the question becomes "why"? And unless you enjoy flaming drivers, what sort of speakers are capable of handling that level of power for any sustained period of time? Sure, transients are a bitch, but a reasonable power-supply at 200 watts will handle them as well as 1,000+ amp.   Peter Wieck Melrose Park, PA

dplatt@coop.radagast.org (Dave Platt): Dec 07 02:14PM -0800 In article <tg8j2d1kto4njteig2h2g538i0s3g08lb6@4ax.com>,   >However, I need a means to send only the bass to the amp that powers the >Subwoofer. Is there any sort of crossover made that goes in the input of >the power amps, after the preamp?   Sure. http://www.marchandelec.com/xovers.html for one.   I use an XM9 in my own speaker system. Each side has a midrange/tweeter/midrange array with a passive crossover, powered by one amplifier, and a side-mounted subwoofer powered by a second amplifier. The XM9 divides the signal, after the preamp and before the amplifiers, crossing over at 200 Hz.   http://www.radagast.org/~dplatt/speakers/   20+ years since I build it, and I'm still thoroughly satisfied with the results.

jurb6006@gmail.com: Dec 07 03:46PM -0800 First of all, combining the channels by definition means losing all the separation. Also do not try to combine outputs of amplifiers, it has a very bad effect on some. It has to do with DC and is insidious, sits there dissipating power uselessly. It can actually fry the amp in certain cases.   They make what you want for cars. Those ones that drive around "BOOM mufuka BOOM mufuka BOOM mufuka...". This is exactly what you want. It is active so it needs power, if 12 volts that is a simple matter because it does not pull much current. A spare wall wart in your junk drawer should do just fine. Most of them also have a continuously variable crossover frequency as well. That comes in handy. Crossover too high and the subs might be too boomy, too low and the highs are taking too much power which they frequently can't use. Some have the option of combining the two channels, but at line level you can do it with two resistors and have practically no loss.   If you want it really loud, you might want a low pass passive filter on the woofers, such as in a regular crossover. This way if the bass amp clips it does not screw up the sound as much. But you probably won't need it. You are not really likely to clip anything with that power unless you have a huge outdoor party. In fact, with some exceptions people go to a party to mingle. For me, I like loud good sounding music, but not the whole time. People who just crank up the radio bug me. When I listen, everybody shuts up while it is playing and then there is an intermission between songs. Then there is time to talk, or maybe take requests, or whatever.   But seriously, go with the active (line level) crossover, you'll be glad you did. Most of them even have level controls, some power amps do not. Solves that, that is burns that bridge if you come to it.   There is a way to combine to a woofer on the output side but it loses a bunch of power and is totally unsuitable for bi-amping. Actually if you want to change your mind and go with four really full range channels, I can build you a little box that is like quad which is almost the same as Dolby surround.I mean native Dolby surround that they should never have been allowed to put their name on because it was so common in the 1970s+. I used the technique for movies with my Advent five foot TV, which BTW was the only one in town with really hot tubes and near perfect geometry and convergence. But like on Days of Thunder you heard the cards actually go around you when the camera angle was that way. The Enterprise would take off and seem to go above you on the screen and the speakers sounded like it. It is good for some music, but not all. Some is mixed funny, like all the bass in one channel, like The Swinging Medallions - Double Shot Of My Bsby's Love or Beatles - Taxman. Those are not suited well for such a system.   It sounds like Dolby without any delay or anything like that. In that respect it is true high fidelity because it only puts out what goes in. With all the effects, Dolby surround is not high fidelity, it bastardises the sound with.   Actually with speaker that have really good imaging it almost sounds like there are rear speakers. But you'll probably not find them with that kind of power handling without mucho dinero, and very low efficiency.   So really, just go to one of those car audio places and tell them what you want, most likely they have it on the shelf already. You don't need an ultra high fidelity one,just low distortion, and very importantly, LOW NOISE. While the levels are line level, you are dealing with it after the volume control. So any noise introduced by the unit will still be there.

tabbypurr@gmail.com: Dec 07 06:13PM -0800 > I'll probably try it, but I have not yet built my subwoofer cabinet.   > Either way, I know that 1100 watts rms is more than enough for a home > stereo...   resistor capacitor (RC) low pass filter.     NT

oldschool@tubes.com: Dec 08 01:07AM -0600 On Fri, 8 Dec 2017 09:00:50 +1100, Clifford Heath <no.spam@please.net> wrote:   >focussed on "the world's most powerful PA - 10,000W!". They >always were more about quantity than quality.   >Clifford Heath.   Funny you mentioned the Altec name. My 600W power amp and the preamp are Altec Lansing brand. The speakers are Yamaha. All of this came from a local rock band who upgraded their sound system, and gave me a good deal because I do a lot of repairs for them. Mostly just mic cables and patch cords, but I have repaired some amps and speakers too. I often go to their shows to help setup their gear, because they need someone to work out the bugs when they setup on stage. As they said, "we're musicians not sound engineers".   The newest amp I got is a Crown brand. 500W.   I really dont need this much power, but I like having the reserve power, that way I get clear sound at normal levels with no overloading. The speakers are 15" Woofers with large horns. I also have a pair of high power home sterao speakers connected. But I plan to build my own subwoofer cabinet, using at least two 15" speakers or maybe one 18".   I built my own stereo in 1968 to 71. I was still in high school, and it outperformed anything you could buy. The all tube amps consisted of 12 6L6 output tubes. My homemade speakers were each about the size of a large refrigerator, with a 15" two 12" two 8" and 2 horns on each channel. Power output was around 250W RMS. I literally blew the window glass out of my living room windows once with it. I was never dissatisfied with the sound. However, due to changing living conditions, having too small of an apartment, not to mention the constant police coming to the door with noise complaints, I put it in storage, until I moved to the farm I now live on. However, moisture affected some of it, and it needs a complete rebuilding to make it usable again.   Until I get to doing that, I got this commercial solid state gear, and I knew Altec Lansing was what I wanted right from the start.   I have heard that Woodstock had as little as 1000W up to 10,000W. I know they used Macintosh tube power amps. Stacks of them......   Are you familiar with the Grateful Dead's "wall of sound". That was considered the biggest sound system ever made at that time (early 70s).   If you like electronics and rock concerts, you'll like these articles and photos.   http://bobbyowsinski.blogspot.com/2011/07/grateful-deads-wall-of-sound.html   https://en.wikipedia.org/wiki/Wall_of_Sound_%28Grateful_Dead%29   [Quote] 89 300-watt solid-state and three 350-watt vacuum tube amplifiers generating a total of 26,400 watts of audio power. 604 speakers total   And there are a lot more websites about this. Google "Wall of Sound".

oldschool@tubes.com: Dec 08 01:18AM -0600 On Thu, 7 Dec 2017 14:14:06 -0800, dplatt@coop.radagast.org (Dave Platt) wrote:     >http://www.radagast.org/~dplatt/speakers/   >20+ years since I build it, and I'm still thoroughly satisfied with >the results.   Yep, this looks just what I want. I've seen these but never knew what they were for....     Thanks

gregz <zekor@comcast.net>: Dec 08 07:52AM > I'll probably try it, but I have not yet built my subwoofer cabinet.   > Either way, I know that 1100 watts rms is more than enough for a home > stereo...   There no need to sum bass in stereo, just use one channel. That can cause that channel to be different with loading. You make easy line level passive, but what order, and how is that going to mix with upper, phase and frequency. Seems like a full active crossover of all three speakers will work best, but you still have to determine order of filter and frequency for combining.   Greg

oldschool@tubes.com: Dec 07 02:16PM -0600 On Wed, 22 Nov 2017 14:39:04 -0500, "J.B. Wood" <arl_123234@hotmail.com> wrote:   >you can simply take, say, a 120 VAC-to-120 VAC isolation transformer and >follow it with an adjustable autotransformer, keeping in mind the >maximum AC current/power ratings of the devices. Sincerely,   I reaad on some website where someone took two 120 to 240 volt transformers, connected both 240 windings together and ended up with 120 on the secondary, completely isolated from the AC line. This makes sense, for someone who has two such transformers on hand. But would not make sense to buy two transformers.

Michael A Terrell <mike.terrell@earthlink.net>: Dec 07 04:17PM -0500 >> bench safety when working on live equipment do NOT make the >> neutral-ground connection.   > Quite. And building site transformers earth the centre tap.     IOW, they convert the European 240volt system to the American 120V/240V system.

tabbypurr@gmail.com: Dec 07 06:09PM -0800 On Thursday, 7 December 2017 21:17:18 UTC, Michael Terrell wrote:   > > Quite. And building site transformers earth the centre tap.   > IOW, they convert the European 240volt system to the American > 120V/240V system.   They output 110v centre earthed, so nothing is over 55v ac from ground. It was the building site standard until RCDs made 110v not really needed.     NT

Michael A Terrell <mike.terrell@earthlink.net>: Dec 08 01:14AM -0500 >> IOW, they convert the European 240volt system to the American >> 120V/240V system.   > They output 110v centre earthed, so nothing is over 55v ac from ground. It was the building site standard until RCDs made 110v not really needed.     Unless they didn't want to replace all their existing power tools?   The wiring is US, even if the transformer is only 50%. Not all of our power tools are 120 VAC. Some are 240, and others are 480 VAC, three phase.

mike <ham789@netzero.net>: Dec 07 10:52AM -0800 > On Thursday, 7 December 2017 11:32:51 UTC, mike wrote:     > I've always thought 12v & 14.4v ones could be run off a car battery   or a small SLA sat on the floor. But really no-one is that short of dough these days.   Glad to hear you're doing well... The conundrum is that the only way to have money is to not spend it. Most people don't have the discipline to plan ahead. > NT >Most of the stuff these days is 18V. There's the issue of the physical interface. How many adapters do you need? How would you hook up that 12V battery...conveniently? How would you get all that up into the attic to drill a hole? Might as well take a corded drill. I'll typically use one drill as a drill and another as a screwdriver. So, I need two batteries that work. Before I went all-in on Ryobi, that meant two batteries and two chargers and advance notice to charge the inevitably dead batteries.   It didn't cost much more to switch to Ryobi than it would have taken to buy a couple of batteries for my junk pile. I'm glad I did. Now, I just grab whatever tool I need and can be sure that I have a compatible battery that is fully charged and ready to go.   Unfortunately, the pack-rat in me can't bear to let go of all the old, useless cordless tools. ;-(

"pfjw@aol.com" <pfjw@aol.com>: Dec 07 12:24PM -0800 On Thursday, December 7, 2017 at 1:53:34 PM UTC-5, mike wrote:   > Unfortunately, the pack-rat in me can't bear to let go of all the > old, useless cordless tools. ;-(   I have used Craig's List CURB ALERT quite often to creatively recycle many things from (no kidding) old toilets to picked-over electronics to random junk. I can honestly state that nothing has lasted more than four days - or the first weekend, whichever comes first. I know now to initiate such alerts on Thursdays. A careful, but accurate description with pictures often helps.   The stuff gets gone, and as someone went to the trouble of coming to get it - I suspect that it will actually get used. Far better than a paper sign "FREE".   Peter Wieck Melrose Park, PA

tabbypurr@gmail.com: Dec 07 06:05PM -0800 On Thursday, 7 December 2017 18:53:34 UTC, mike wrote: > There's the issue of the physical interface. > How many adapters do you need? > How would you hook up that 12V battery...conveniently?   that's easy, just fit a cord to the drill. Forget the old battery pack case. SLA then sits on the floor near you. FWIW it would make the drill smaller & lighter - someone somewhere in the universe must have a use for that.   > How would you get all that up into the attic to drill a hole?   Is it a struggle to take a 7 or 12Ah battery with you? It would beat the heck out of a 1.3Ah NiCd for run time.   > Might as well take a corded drill.   An SLA powered drill wouldn't need mains and would be much lighter.   > a compatible battery that is fully charged and ready to go.   > Unfortunately, the pack-rat in me can't bear to let go of all the > old, useless cordless tools. ;-(   One thing I'm not short of is drills. They're fairly versatile.     NT

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.