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Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Mar 29 07:17AM +1100 On 29/03/2016 3:20 AM, Cydrome Leader wrote: >> back to the owner (until it did).   > It is sort of sad it can't handle that. Just a few warranty service calls > would pay for hundreds or thousands of fuse to have been installed.   **Fuses open in seconds. Semiconductors can fail in MILLISECONDS. Active current limiting is the best solution.   -- Trevor Wilson www.rageaudio.com.au   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

jurb6006@gmail.com: Mar 28 05:21PM -0700 >"When would you use a diferent preamp, or different power amp in an >integrated unit anyways? Anything with the shunts was already packed >with >all sorts of silly inputs to start with. "   Preamps can make as big a difference in the sound as power amps. People also get to liking how they hook up, all their shit fits. They like the tone controls, and that is a big one. some of those old 25 WPC Marantzes had fantastic preamps and tuners, but now the guy went and bought some speakerzillas and needs more power. So he picks up an ampzilla somewhere but wants the rest of his system to stay the same. He likes how it looks and sounds, just needs more power.   That's why, and it really is not audiophoolery, just one of thoise things.   I had a Marantz 4270 I ran in strsapped mode for the front to get the more power (clipped at 154 watts per channel in bridged mode) and used the rear pre outs to feed a Sansui 771 into 2.3 ohms for the back which had modified speakers. They originally had passive radiators but I put speakers in there instead. Then I had to use an EQ (Soundcraftsmen PE2217) to get the sound right.   Purists can bitch and moan about using EQ like that but what about the Bose 901 ? The EQ for that has about a 30 dB range that a standard graphic EQ cannot do. So if that is OK then my system was OK.   All of this shit can sound different, so if you got a receiver or amp and like the sound, you can keep it. Also, people are getting back into vinyl and phono preamps are not all created equal. All over the place the audiophiles say my Soundcraftsmen has a shitty phono stage, that it sounds harsh. Well I never used it, I used the EQ and it is one of the best EQs I have ever seen. Uses real coils, and the way it is configured, when you get to the extremes in the ranges, they are pretty much effectively in parallel. the chip based ones cannot do that and give you camel humps in the response. I can show you on a scope with a 1 KHz square wave.   People do crazier shit than that when it comes to stereo equipment. Some go nuts and claim one speaker wire sounds better, I do not go for that. Unless the resistance is very high it makes no difference. And like the cables, RCA type, the only thing that matters in them is the capacitance per foot. A cable from a turntable with a moving coil cartridge, maybe. then you might need superior shielding. but for the rest of it, for electronic sources like a CD player or tape deck, you almost do not need shielded cables. I'll use Romex from a CD p;layer to an amp and nobody will hear the difference, or might actually think the Romex sounds better !   Learning a little bit of math and electronics makes you aware of what really matters and what does not.

jurb6006@gmail.com: Mar 28 05:39PM -0700 >"**Fuses open in seconds. Semiconductors can fail in MILLISECONDS. >Active >current limiting is the best solution. "   Yeah like when seconds count, the cops will be there in minutes. Completely true. The problem is the implementation.   Active current limiting tends to make bad bad distortion on low impedance loads. It sounds as if a speaker is blown or a woofer is bottoming out.   I have tried to figure out a better way but am at a loss on that, so I understand why they did it. It protects their product from abuse and unnecessary warranty claims. And it was cheap, couple transistors, diodes, maybe six resistors in all.   The alternative is to use a relay and a latch, which is run through the uProcessor on newer shit and it reads "Protection" on the display. I am not fond of those type of circuit because it makes it harder to troubleshoot.   I think they should make amp ready to drive one ohm loads, but then they would be more expensive and sales would be lost.

Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Mar 29 02:03PM +1100 > Active current limiting tends to make bad bad distortion on low > impedance loads. It sounds as if a speaker is blown or a woofer is > bottoming out.   **Nonsense. There are several methods of implementing current limiting, which do not impact severely on sound quality. If the current limiting can be kept out of the global NFB loop, then the result can be very benign.   > harder to troubleshoot.   > I think they should make amp ready to drive one ohm loads, but then > they would be more expensive and sales would be lost.   **That is the way high quality products do it.       -- Trevor Wilson www.rageaudio.com.au   --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

jurb6006@gmail.com: Mar 29 09:34AM -0700 >"**Nonsense. There are several methods of implementing current >limiting, >which do not impact severely on sound quality. If the current >limiting >can be kept out of the global NFB loop, then the result can be very >benign. "   They're all benign when not active. I am talking about when they are working actively limiting current. Maybe I didn't make that clear.   But if I did, and there is a scheme that will limit the current actively without that harsh distortion, show me. A model number will do now that with the internet I can usually get a print.   I saw one, in fact owned it. But it was not DC coupled and I don't remember the model. It was a Realistic integrated amp, maybe 40 WPC or something like that. Overload it and it seemed like the gain decreased, it didn't bark at you. But it also was not all that high end or high power.   >"**That is the way high quality products do it. "   At the cost of market share of course. I agree though, just build it right and use like 12 amp speaker fuses.   HA, I remember Heathkit touted that their speaker fuses were in the feedback loop. Actually, the audiophile crowd kinda likes them.

"Michael A. Terrell" <mike.terrell@earthlink.net>: Mar 28 03:53PM -0400 John-Del wrote:   > Don't waste your time trying. CRTs don't short that way. If the CRT is full of air, the tube will arc loudly. You could ground the second anode cup to the metal frame and it still won't smoke the flyback. Any secondary short will destroy the horiz output or open the B+ fuse (or both) way before the flyback can smoke. If the flyback smokes, it's bad.     I used to get dead monitors from a Burroughs service tech, and some of the CRTS were shorted internally. That caused spectacular failures, when they shorted. Just because you have never seen one doesn't mean that it can't happen. These were 12" TTL input monitors for computer terminals and they had some internal welds that had failed.

jurb6006@gmail.com: Mar 28 05:51PM -0700 Shorted/leaky anode to ground (dag ground) was pretty common in 32" Sonys of a certain era. I am not sure exactly what happened to them, I know the Hstat block was built in but that is not likely to short, it would go open. (and they did not)   I am thinking some sort of problem with the glass or something. There is no path to ground except for the grounded aquadag. The ones I found shorted were still shorted when the CRT socket is removed, it was not an anode to cathode or whatever short, it had something to do with the dag.   Maybe a slight little blow hole in the glass, and a subsequent (after years) carbon track through there. And some of these CRTs tested good on a tester. Just the HV was a dead fucking short.   This is because CRT testers cannot test the whole thing. There were two types, one was an emission tester and the other a beam current tester. The emission tester was cheaper and simply measured current to G1. The beam current tester which was capable of more accurate readings measured current from G2. Some of the better testers had a function to check G3 (focus electrode) leakage but none of them stuck 20 KV on the anode. It was impractical to do that.

John-Del <ohger1s@aol.com>: Mar 29 04:18AM -0700 > Shorted/leaky anode to ground (dag ground) was pretty common in 32" Sonys of a certain era. I am not sure exactly what happened to them, I know the Hstat block was built in but that is not likely to short, it would go open. (and they did not)   > I am thinking some sort of problem with the glass or something. There is no path to ground except for the grounded aquadag. The ones I found shorted were still shorted when the CRT socket is removed, it was not an anode to cathode or whatever short, it had something to do with the dag.   > Maybe a slight little blow hole in the glass, and a subsequent (after years) carbon track through there. And some of these CRTs tested good on a tester. Just the HV was a dead fucking short.   You're right. I forgot about those earlier Trinis. I think I saw maybe 2 or 3 tops shorted in the second anode ( the ones that used the coaxial anode connector). Replace the SG613, damper diode, and 867A regulator with Sony factory parts, and they'd blow up in a split second. Still didn't damage the flyback. Later Trinitrons did not have this problem.

jurb6006@gmail.com: Mar 29 09:24AM -0700 I didn't mean those, I meant the later ones with the kamikazi power supply using I think the 2SC4834s.   If I am not mistaken, those 2SG613s mostly blew because of a drive fault. Lose the negative pulse to the gate and it stays on too long and boom.   In the earlier ones, I think the SRC (sine resonance choke) saved alot of flybacks from overload. The SRC was there to increase the efficiency of the HV rectifiers.   Talk of these Sonys brings back a memory. I was working on a stock 26" console. (you know a toilet seart manufacturer made those cabinets, the only one could meet the specs, and like three guys could sit on top of one and you can still roll it across a thickly carpeted floor) I was pulling the control unit from the front and somehow caught the CRT board and broke the neck.   I thought ih shit, there goes a couple hundred bucks, but that ain't how it is. Under warranty all you sent back was the neck of the CRT. They said to write it up as "unable to get good convergence". I almost had to laugh, with the neck broken like that, damn right I can't get good convergence. They even paid me to change it ! Well after all Sony paid them.   Really, it was dishonest but things like that happened VERY rarely.   And now I work for factory service for RSQ, which is a marketer of Karaoke machines. They are cheap Chinese or Korean built, but what isn't anymore ? They are actually modified DVD players. In the same building is a retail outlet for them and a few other things. It's like I got two jobs in one. But anyway, they do not record the serial numbers or anything. If I fix something and it breaks again nobody has any way of knowing. Also, as I pointed out to them, the customers could rob us blind if they knew.   Good old American business, but the money spends just fine.

"Michael A. Terrell" <mike.terrell@earthlink.net>: Mar 29 11:13AM -0400 Jeff Liebermann wrote: > cool toys and just make fun of the nerds. Then, we all grew up > together. Today, I'm being chased by about 5 women (I sometimes loose > count).     A loose count? ;-)

Jeff Liebermann <jeffl@cruzio.com>: Mar 29 08:52AM -0700 On Tue, 29 Mar 2016 11:13:48 -0400, "Michael A. Terrell" >> together. Today, I'm being chased by about 5 women (I sometimes loose >> count).   > A loose count? ;-)   Freudian slip. I'm only being chased by a few loose women. Remind me to have a talk with my proof reader.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"Michael A. Terrell" <mike.terrell@earthlink.net>: Mar 29 11:27AM -0400 Gunther Heiko Hagen wrote: > > icy cold to hide the fact that it tastes bloody awful. QED.   > > :)   > They don't appear to use hops for flavouring in N. America     Then explain why Florida has started farming hops instead of oranges, in many places.

Jon Elson <elson@pico-systems.com>: Mar 28 10:22PM -0500 Jeff Liebermann wrote:       > This is the one that I bought for my various microscopes and cameras: > <http://www.ebay.com/itm/311570447425> This still fits below the black cone of the microscope objectives, and is larger in diameter. What I made fit around the upper part of the black cone, just under the ring that holds the microscope. So, it is much less in the way of your hands, tools, etc.   Jon

"Dave M" <dgminala@mediacombb.net>: Mar 28 10:46PM -0500 Jon, What are the dimensions of the light ring (ID, OD, thickness)? Im thinking of another application for it. I asked the seller and he/she replied that all the data about the item was in the description. The only dimension that I saw in the description was the mounting diameter (61mm max).   Dave M   Jon Elson wrote:

Chris Jones <lugnut808@spam.yahoo.com>: Mar 29 09:27PM +1100 > I need to purchase a magnifier so that I'll be able to do things like replace eproms and other small SMT's. I'm not looking to do LSI's with 150 pins Etc. Just mostly smaller stuff. For instance I currently have a board that needs an 8 pin Eprom replaced. I thought that I could do it with the magnifiers I have but the stuff is Just too small. I tried using a high res TV camera with a varifocal 3.5 to 8 mm lens but it doesn't make the image large enough. I was wondering what people are using to do this. Thanks, Lenny   Nikon SMZ645/660 (used) or SMZ745 (new), on a boom (can be home made), ideally with a ring light.

"Gareth Magennis" <soundserviceleeds@outlook.com>: Mar 29 12:34AM +0100 wrote in message news:6845af1b-74c5-4fce-9709-80104f9d3d65@googlegroups.com...   On Wednesday, March 23, 2016 at 8:01:33 PM UTC-4, Gareth Magennis wrote:   > I don't have a Summer House.   > Gareth.   Dust + nicotine/kitchen grease/smoke/creosote = nothing what you describe could handle. Point being, as stated, what is desired is not practical, what is practical may not be convenient. FULL STOP.   Peter Wieck Melrose Park, PA           Peter I really don't think you get this at all.   I only want to blow dust off a heatsink. I can actually do this myself by taking a big breath and blowing hard. But I really don't want to do that, and I don't want a large compressor plus tank I have to store somewhere to do this for me. I'd have bought one years ago if I had wanted to do so, I have been well aware of these things for years.   Inventing reasons I need something else to shift nicotene, grease, smoke etc is not helpful. Full Stop.       By the way, I have an emergency tyre in the boot of my car, that claims it is charged to 60psi. I bet I could fit an attachment to this to provide short bursts of air that would be far more effective than anything I can do by blowing hard, and it has the right attachment for blowing up at any local garage. http://www.puretyre.co.uk/tyre-information/tyre-definitions/space-saver-tyre/   I just need a smaller tank to do the same job.       Gareth.

T i m <news@spaced.me.uk>: Mar 29 11:23AM +0100 On Tue, 29 Mar 2016 00:34:20 +0100, "Gareth Magennis" <soundserviceleeds@outlook.com> wrote:   <snip>   >I only want to blow dust off a heatsink. I can actually do this myself by >taking a big breath and blowing hard.   I've done that for someone on an overheating PC but using a thin tube to better direct the air and get my face out of the way. ;-)   >But I really don't want to do that, and I don't want a large compressor plus >tank I have to store somewhere to do this for me.   I've not read the entire thread but I have a very portable and 'adequate' instant / oil-free, non reservoir compressor I regularly use for blowing out PC heatsinks and cases and have done so for many years now (to good effect).   http://nbwelly.en.made-in-china.com/product/EeyQOYrlbXWg/China-1-5HP-Oil-Free-Portable-Air-Compressor-Without-Tank.html   http://tinyurl.com/hn3xonj   My mate (who owns his own PC repair shop) has the exact same and has been using his for a similar period. The only thing against them, you do need power and they are pretty noisy (but aren't generally running for long). Personally, I leave mine just inside an external door, just close the door on the hose and blow the item clean outside (so not so noisy).   <snip>   >has the right attachment for blowing up at any local garage. >http://www.puretyre.co.uk/tyre-information/tyre-definitions/space-saver-tyre/   >I just need a smaller tank to do the same job.   As I believe has already been mentioned, you don't get a lot of 'compressed air' when you aren't compressing it to very high pressures so you may be stuck with something that is still reasonably bulky. A spare wheel may well be good enough and as you say, already has the right connections, at least for inflation. ;-)   I bought one of these to do exactly the sort of thing you were talking of:   http://www.toolstation.com/shop/Power+Tools/d40/Air+Compressors+%26+Accessories/sd3147/Trade+24L+Air+Receiver/p19659   http://tinyurl.com/zjonb68   I have to admit I've not used it yet but I hope to soon, both to expand the capacity of my small silent workshop compressor (Bambi) and to have something in the indoor workshop for the odd small blowing out job (that I can re-charge myself down the workshop on the other compressor).   Cheers, T i m

Jeff Liebermann <jeffl@cruzio.com>: Mar 28 07:21PM -0700 On Sat, 26 Mar 2016 19:56:12 +0000 (UTC), Andre Majorel <cheney@halliburton.com> wrote:   Sorry for the delay but I missed the followups to my comment.   >> a soldering iron tip.   >News to me. In what way are multi-layer ceramic caps and >soldering irons incompatible ?   Thermal shock easily cracks MLCC caps. I learned that the hard way while fixing several Apple Mac Mini computahs, which feature a collection of MLCC on the bottom of the main board. <https://web.archive.org/web/20130606062903/http://blog.helpmymac.ru/?p=3585> The original failure mode was shorted MLCC caps caused by either thermal shock or board flex. The bad ones were easy to find with an ESR meter. However, when I tried to install replacements (and guessing the part value because Apple doesn't supply service information to non-authorized repair shops), I managed to crack and short several known good MLCC caps with a soldering iron. Having learned the lesson, I used some solder paste and a hot air SMT reflow gun to do the soldering. I also pre-heated the PCB and let the caps cool down slowly. I don't know if that was necessary, but it worked every time. I'm told that two solding irons used as a tweezer also works, but I haven't tried that yet.   You'll find some more details under: <https://www.google.com/#q=mlcc+capacitor+crack> <https://www.google.com/#q=mlcc+capacitor+soldering+iron> Lots of articles and guidelines on handling and soldering these caps, some of which warn about using a soldering iron. For example:   <http://www.vishay.com/docs/45034/soldrec.pdf> 6. Soldering with a Solder Iron Attachment by soldering iron is not recommended. A heat shock may cause a crack in the MLCC chip capacitors, however, if solder iron is used, the following precautions should be taken: ... (etc)   Damage Prevention When Soldering Ceramic Chip Capacitors <http://www.eptac.com/webinars/presentations/eptac_09_17_14.pdf> Hand Soldering - A pencil type soldering of 30 watts maximum and with a diameter of 3 mm maximum should be used. - The soldering iron tip temperature should be less than 300C [572F] and maximum contact time should be 5 seconds. - The soldering iron tip should never come in contact with the component body. Ever try to solder a small MLCC cap without touching the body with the soldering iron tip? Good luck.   <http://www.murata.com/en-us/support/faqs/products/capacitor/mlcc/mnt/0001> In order to prevent damage (cracks) to the component that can be caused by localized rapid heating and heat shock, preheat the chip, for example, to prevent it from being subjected to heat shock.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Jon Elson <elson@pico-systems.com>: Mar 28 10:15PM -0500 Jeff Liebermann wrote:     > cool down slowly. I don't know if that was necessary, but it worked > every time. I'm told that two solding irons used as a tweezer also > works, but I haven't tried that yet.   I've heard these stories a number of times. And, yes, maybe some people use insanely hot irons or in some other way cause this problem. And, some really large caps are prone to this damage. But, as I say, I have hand- soldered over 25,000 0805 MLCC caps of modest value without seeing this problem. I use a very good Weller temperature-controlled iron, and run it at a modest temperature. Much better to use an iron with really good thermal conductivity at a lower temperature than one with poor conductivity at a very high temperature.   Jon

mike <ham789@netzero.net>: Mar 28 12:57PM -0700 On 3/28/2016 8:48 AM, Cydrome Leader wrote: > It can be impossible to get the batteries out. I had a Kel-Lite destroyed > that way. Somebody on usenet suggested wrapping the cells in saran wrap > so if they leak you can just slide the whole mess out.   That probably won't help. You have to pull them out and there's nothing to pull on. I had a maglite with that problem. I had to saw it in half to get a look at the markings on the battery. Was Duracell. Sent them a picture. They sent me the cost of the light.

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