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Bronze Member Username: EnjoythemusicPost Number: 48 Registered: Sep-04 | Hi Everyone, Enjoy the Music.com's November Review Magazine plus the fall 2010 edition of the DIY Magazine are now available. The Review Magazine has two world premiere equipment reviews, our RMAF show report, music reviews and much more! The DIY Magazine has three new great projects plus two revisits for your enjoyment. ------------------------------ REVIEW MAGAZINE ------------------------------ Viewpoint In This Issue... Getting Less Bored And other ranting. Article By Steven R. Rochlin Audiolics Anonymous Chapter 133 Caig DeoxIT GOLD, Kaleidoscape M-500 disc player and much more! Article By Dr. Bill Gaw Show Report RMAF 2010 (Rocky Mountain Audio Fest) Daily live RMAF 2010 show report updates! Audiophile Equipment Reviews World Premiere! MK1 Boxed M2Tech hiFace Evo USB To S/PDIF Converter Plus the Halide Design Bridge and John Kenny Mk1 boxed hiFace Review By Mike Galusha World Premiere! Virtue Audio's Dodd Modified Sensation M451 Integrated Amplifier Review By Ron Nagle Revisit: Canal Earphones: Shure E4c Versus Ultimate Ears Super.fi 5pro Review By Phil Gold Revisit: LiTe DAC-Ah And Baddymod LiTe DAC-Ah Review By Phil Gold Revisit: Slim Devices Squeezebox 3 Network Music Player Review By Scott Faller Music Reviews Classical Music Beethoven works for Cello and Piano Vol 2. Review By Phil Gold A rare world premiere recording highlights a charming collection of Trios. Review By Joe Milicia Jazz, Bluegrass, etc. Dierks Bentley Up On The Ridge Hamilton De Holanda Quintet Brasilianos 2 Peter Ostroushko When the Last Morning Glory Blooms Yarn Come On In Various Bluegrass, Blues And Jazz Albums See the November Review Magazine at www.enjoythemusic.com/magazine/ ----------------------- DIY MAGAZINE ----------------------- The Blue Velvet Line Preamplifier An update to an already great design! Article By Dick Olsher Inigo Phono Stage 1.0 Article By Grey Rollins Building Oblate Spheroid Waveguides Far and away the most difficult project I've done to date. Article By Jeff Poth Revisit: Occam Audio MTM4 (Kit B option) A fantastic small speaker! Article by Jeff Poth Revisit: Hawthorne Audio Sterling Silver Iris Duet Loudspeaker A hand-crafted, one-of-a-kind easy DIY speaker project... or assembled! Article By Clarke Robinson See the fall 2010 DIY Magazine at www.enjoythemusic.com/diy/ |
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Gold Member Username: MagfanUSA Post Number: 1758 Registered: Oct-07 | I paged over to DIY magazine and will place mark it. A few good articles, including one on Power Supply Design which Plym should read. Article discusses ripple, transformer selection and capacitance along with posting several basic schematics........I'm taking notes. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 15508 Registered: May-04 | . I've heard the Hawthorne's twice at shows here in Dallas. http://enjoythemusic.com/diy/1108/hawthorne_audio_sterling.htm The second time I heard them they sounded awful and the folks from Hawthorne were really struggling with the issues of the room. The first time I heard the speakers, the year prior and in pretty much the same hotel room set up, they sounded quite interesting. They were not what I walked away remembering from the show for the most for the most bang per buck but they were an intersting speaker that had some very attractive qualities. The little Adire driver here; http://enjoythemusic.com/diy/1108/occam_mtm4.htm is one many of us recognize from Tim Forman's designs. It could be a simple recommendation for someone willing to screw together a few pieces to save some cash. . |
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Platinum Member Username: PlymouthCanada Post Number: 15416 Registered: Jan-08 | Leo I saw the DIY power supply article yesturday morning, good article for new beginner but nothing new for me. In late end 79-80's, I worked like repair man of electric lift-trucks and handling electric equipments, the high powered charging system used much more complicated and powerfull power supply. |
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Gold Member Username: MagfanUSA Post Number: 1762 Registered: Oct-07 | I'm sure you saw the part about transformer and cap sizing. Did you ever get the temperature derate for your output devices? The 150c you quote (data sheet, such as it is) is very hot for a semiconductor. Try running the CPU in your confuser at that temp. My CPU is currently 76f but will get hotter. Graphics chip runs too hot, IMO, but I have the fan(s) at pretty aggressive settings. |
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Gold Member Username: Nickelbut10Canada Post Number: 3271 Registered: Jun-07 | 150c? Please tell me someone isn't running the CPU at 150c.lol. That is impossible. Leo 76f is a nice temp. |
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Gold Member Username: MagfanUSA Post Number: 1766 Registered: Oct-07 | CPU will run to 85 or 90f. I downloaded aftermarket fan control w/full temp readback.....for my MAC. I get nervous over maybe 110...and being a little obsessive, always run as cool as possible. The 150 refers to Plyms output device spec. I think if he runs them that hot, they'll be derated maybe 30% or more. |
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Platinum Member Username: PlymouthCanada Post Number: 15417 Registered: Jan-08 | Leo I think the temp protection is set to 120c but it does never happened that the amplifier goes in protect mode. |
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Gold Member Username: MagfanUSA Post Number: 1770 Registered: Oct-07 | Makes a HUGE difference where the sensor is located. Is it just a thermister? 120c on the heatsink will be much hotter on/in the device. IF your heatsink compound is a little old/ dry, it could even be worse. Too much compound could almost be as bad! That you've never tripped the 120c setpoint is a good thing. Cooler=better. The 150c mentioned in your datasheet? I think that's a MAX value. I know that if your confusers CPU was that hot, it'd cut into its lifetime. After 45" of running hard, my CPU is still under 90f / 31c. My last PC had a Zalman 'mushroom' cooler of Al/Cu and I ran the fan full speed, simply removing the fan rheostat. Never got above about 115f / 45c. which was good, since I had it configured for an automatic 10% overclock upon need. Total de-dust was an annual event. |
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Platinum Member Username: PlymouthCanada Post Number: 15418 Registered: Jan-08 | Leo I can't found my service manual including parts numbers, I based it on my memory then I can't see the part number because an insulating material hides the part, the thermic protector is placed in a half inch beside of the first transistor on the heat sink. 150c is certainly the max value, A CPU does not live to this high temp because of the quantities of part include inside like micro capacitors, I de-dust 2 or 3 times a years, overclocking is not my way of working vue the highly using of paths of the processor with many addition of cards like PVR and video treatments. |
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Gold Member Username: MagfanUSA Post Number: 1772 Registered: Oct-07 | Plym, There are many semiconductor failure modes related to heat. While diffused junctions don't migrate at those temps, Aluminum sure does...which is why they aren't pure aluminum. Silicon at 1% is common since that is the eutectic ratio....aluminum won't absorb more than that, which prevents 'spiking' the contacts at sinter/anneal. Copper is also added. This forms a 6000 series aluminum alloy which is heat treatable...again, at sinter or anneal..... Aluminum migration is worse at higher temps, too. The heat of deposition in a typical sputter system is nowhere near 150c. Current density over steps in the geometry of a device will cause migration at that point and an eventual 'fuse'. Warmer deposition also will result in cloudier metal which is bad when it comes time to pattern....a photolithography step. The very thin metals....on the order of fractions of a micron, will be easier to keep shiny...indeed, it is possible to have metal TOO shiny to pattern properly, so an anti-reflection coating is used. This is usually pure silicon, also applied with a sputter system. In the case of power devices, which have many different geometries of construction, heat always causes a derate of performance. This is part of the characterization of the device and is usually done in cooperation with the reliability people in-house. Just for info purposes, new devices, when qualified get quite a number of tests including a 1000 hour burn in.....which if too many devices fail, is a deal breaker. I don't know how a CPU is qualified except that they must be installed in a 'simulator' and 'worked'....testing all pathways totally measured for current draw and heat emission. Heat and temperature are 2 DIFFERENT things. |
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Silver Member Username: SuperjazzyjamesPost Number: 288 Registered: Oct-10 | Leo, what would you say is the maximum safe temp, in general that semiconductors should be exposed to? 120c or lower? |
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Silver Member Username: SuperjazzyjamesPost Number: 289 Registered: Oct-10 | Plymouth, I went to that link you posted with the pipe organ (64 ft), my office walls were vibrating! If you don't have sub on your PC, you should get one! |
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Platinum Member Username: PlymouthCanada Post Number: 15422 Registered: Jan-08 | Super I have a Cambridge 5.1 surround system on my PC then the PC is also hooked on my Yamaha Home Theater. I also tested it on my Power full system with 15" woofer in the garage, sh1t the wall shake like for a earthquake. LOL! |
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Silver Member Username: SuperjazzyjamesPost Number: 290 Registered: Oct-10 | You're crazy Plymouth! |
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Gold Member Username: MagfanUSA Post Number: 1777 Registered: Oct-07 | No can give definitive answer to temp question: What you know is 1. heat eats into lifetime. 2. cooler better. Even your automatic transmission lasts longer when properly cooled! 3. some devices MAY be better than others at withstanding the effects of higher temperatures. OR some technologies. For example:: MOSFET vs BiPolar. 4. MAYBE larger devices (physical size of die) are worse because the heat takes longer to 'migrate' away. 5. Everything plays into it. Case style (TO3 / TO5) and MANY others. How well it's mounted to a heat sink...if any sink at all, as well as proper amount and type of heatsink compound as well as how much and what kind (forced or ???) (brain malfunction) cooling is available. Many types of cooling are out there from heat pipes to active chilled water or other coolant. wacky. http://www.datasheetcatalog.org/datasheet2/e/0zf3pdikxlocixte6a8ao25pkayy.pdf Now, I'm NOT a test or probe guy. I spent my entire career building this stuff.... but on the data sheet I see a few I can figure out. Ic= collector current max Pd= power dissipation in watts Bv cbo or ceo Breakdown Voltage...and I guess 'c' is collector 'b' is base and 'e' is emitter....so these are bipolar, not MOSFET which have Gate Source Drain. It isn't a lifetime problem but SETI searchers put their amps into LN2 (liquid nitrogen) to reduce the noise of atoms bumping into one another.....thermal noise. I suspect the 'last word' in the quietest home gear would be built with a similar strategy. Liquid nitrogen is a drag to have around and in a confined space CAN displace ALL the air, which is about 20% O2 and you will perish by suffocation. I went to test site and my earbuds WILL produce 30hz easily. Got some output at 20 but didn't try the organ piece with the 16hz pedal tone. Maybe...I'll do so. Cone woofers can 'double' where they will produce a tone 2x the frequency fed them. I don't know if my panels are prone to a similar problem. I DO know that I don't want to play that disc again in my home system. It was a violent assault on the entire house. I could see the windows vibrate by looking at something in the reflection. |
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Platinum Member Username: PlymouthCanada Post Number: 15423 Registered: Jan-08 | Leo My amp run under about 50-60c without fan, under 2 ohms I add a fan to prevent failure. To easily produce a16 hz frequence 2 things are needed, a big transducer or high displacement transducer then a huge room as a church, with these 2 conditions we can hear easily this frequence but in our houses this sound is passed on directly on walls. Few years ago for a friend, I made 2 big speakers for mobile discotheque with two 15" in each one, a big mid horn and 6 piezo tweeters then I calibrated these loudspeakers in my basement with my equipments, the dimension of the room was 32' X 16', later we tested these speakers in a huge room then the result was disastrous, the sound was too much loud in the deep bass. The dimension of the room play on the lower frequencies. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 15512 Registered: May-04 | . "Cone woofers can 'double' where they will produce a tone 2x the frequency fed them. I don't know if my panels are prone to a similar problem." What you've stated is some "common knowledge" that is for the most part factually incorrect or, at best, a semantic jumble. All drivers will respond to a signal, they will all also have a low frequency roll off which is determined by the type of enclosure or, in the case of open baffles and panels, the lack of a baffle. The open baffle system results in low frequency cancellations as the long low frequency wavelengths wrap around the edges of the frame supporting the driver and "+" going wave is cancelled by the "-" going wave. To achieve good in room bass response with open baffles, the user must position the drivers at a location in the room which reinforces specific frequencies while allowing for the near to total cancellation of all others where the wavelength is longer than the dimensions of the baffle. "Bass response" with open baffles is mostly a falsehood in anything other than an anechoic chamber. http://www.stereophile.com/floorloudspeakers/303/index6.html "Doubling" is not so much a function of the driver but of the listener's ears and the way music is constructed. As the useable response from the driver rolls out the driver will continue to respond to a signal, we understand that as the driver has no choice but to move when the amplifier says, "Move". The fundamental frequency quickly disappears and we are left with flopping woofers which produce significant harmonic distortion which then increases rapidly as the driver is pushed further outside of its response range. In addition to this rising distortion component of the driver, the second harmonic of virtually any acoustic instrument (and most electronic instruments which emulate music) will be significantly higher in level than will the fundamental - sometimes as much as 20 dB higher. Third and fourth harmonics are also quite high in level and it is from these upper harmonics that we conclude we are hearing "X" frequency as the fundamental. (This is the basic function of a subwoofer crossover and how our brain assumes the position of the frequency is not located at the subwoofer itself.) Therefore, as the useable response from the driver rolls out, we are left with a strong second harmonic which, being higher in frequency, is still within our hearing bandwidth. If we take, say, a 20Hz signal which is all but gone from the driver's useable response what we will be hearing are the strong harmonics at 40, 60, 80, 100Hz and above. This is the "doubling" you mention and with music material is a combination of driver distortions and instrument harmonics. Even running single frequency sine waves you are likely to be hearing the strong upper harmonics created by the driver's distortion component. As the driver looses its response at the lowest frequencies this distortion component rises in level which frequently leaves us with a Doppler Effect of our ears/brain perceiving a lower or higher frequency (depending on which end of the scale we are at) than actually exists. All in all, "doubling" is our misperceived and often uninformed assumption of a lower bass frequency than the driver can reproduce or the room can support. It would take quite an enormous room to fully support a 16Hz wavefront which is 68' peak to peak. As P suggests such long wavelengths typically pass through walls and our neighbors hear those fundamental frequency thumps and the harmonic structure of the wall where only minimal absorption can take place. (The wall has its own harmonic structure which is not in tune with the musical note and which gives us the familiar "Purple Honda" thump composed primarily of out of tune harmonics.) What we perceive within the room is limited by the dimensions of the room, compounded by standing wave cancellations which result in large peaks and dips to the in-room response of a speaker and most average listening rooms have difficulty supporting even a low "C" organ pedal at 32Hz. leo, I'd be very surprised at any earbuds which can reproduce 30Hz and even more surprised to to find them doing so "easily". Closed membrane phones have a much better chance at reasonable low frequency response than do open cell or earbuds but it's difficult to find good closed membrane headphones nowdays. What brand and model of earbuds do you own? "I DO know that I don't want to play that disc again in my home system. It was a violent assault on the entire house. I could see the windows vibrate by looking at something in the reflection." I'm sure you know this is not the 16Hz which is rattling windows and so forth but rather the upper harmonics of the signal which are occurring at frequencies sympathetic to the resonant frequency of the object set in motion. If a small picture has a resonant frequency which is in the 200Hz range a strong 40, 50 or 80Hz signal (or higher) with its rising harmonics will likely set the picture in motion. . |
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Silver Member Username: SuperjazzyjamesPost Number: 291 Registered: Oct-10 | My mistake Leo, is that I asked the question when I was very tired. So I left out important details. How about a very heat sensitive semi conductor that is attached to an inadequate heat sink and the compound is either old, poor or applied wrong? The reason I ask is because I've always tried to keep the temp below what the weakest device can handle. It's like using a chain to hoist a heavy load and knowing that the weakest link can only handle 500 lbs. It doesn't matter what the rest of the links can handle, if you exceed 500 lbs, the weak link breaks and we have a disaster. So if I know that a semiconductor in the above scenario, will only handle 120c, I'm going to do what I have to to avoid any of them reaching that temp or above. Does that make sense? |
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Gold Member Username: MagfanUSA Post Number: 1780 Registered: Oct-07 | 100% :: cooler is better for all the circuitry. However, I left out one consideration. TOO cool in a HUMID climate can cause other problems. Condensation will kill the works. Add 'Non-Condensing' and I think that covers it. Any way to get some professional help and get the transistor remounted with proper compound and tightness? Any way of finding a more heat tolerant device with identical electrical properties? What kind of device? TO-3 are the flat packages that mount flat to a heatsink. TO-220 are common, too. In the Wiki article.....trust what you will, the pictures are OK, they list an IRF part#....a 5.6A / 100v power transistor. Might work for audio? Get 'em in PNP / NPN pairs for a push/pull output. http://en.wikipedia.org/wiki/TO220 TO-5 is the little vertical can which won't take much juice, though I have seen little wrap-around fin sinks for them. I wanted to touch on something Plym said in a post......way above, about 'micro capacitors' in semiconductors. As far as I know, NO plastic, ceramic, or bees wax is inside ANY semiconductor device, even elaborate CPU constructs. Though, Aluminum Oxide IS a ceramic, methinks? Capacitors are formed anytime 2 conductors are separated by an insulator. In semiconductors, SiO2 is the insulator of choice, either grown from the native silicon....you are, after all, building the device on/in a silicon wafer OR by deposition. You can flow Silane gas which is SiH4 and is NASTY to the extreme. It is pyrophoric which means it burns on contact with air. It doesn't like water, either. Anyway, Silane and Oxygen in the proper conditions will put a controlled layer of oxide on a wafer. Some devices have this as a last step called 'passivation' which is used to protect the circuitry under. To oxidize silicon you should be above say......900c and sometimes as high as 1100c+. You do this operation in either pure Oxygen or sometimes add Hydrogen to form STEAM. Careful with that H2/O2 ratio or you'll blow the place up! Silane / Oxygen mix can be done a very low temps......say over 400c and it isn't all that sensitive. Sometimes phosphorous is added to make the film 'softer' and improve etchability. Both the above films are used in semiconductors but they are NOT interchangeable. Oxidations are typically done early in the process while deposited films come later. I think UNDOPED polysilicon (another, non-crystaline) form of Silicon can also be used as an insulator. This is tough stuff and may not be suitable. Temps above about 600c are needed for this reaction and it is VERY sensitive to this temp...... |
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Silver Member Username: SuperjazzyjamesPost Number: 292 Registered: Oct-10 | Thanks Leo, I guess between what you've said and your link, that's about as specific as is reasonable to expect. The condensation issue was my next question, but you already answered that. We should all be thankful for air conditioning I've heard rumors about plastic, ceramic and other materials were being experimented with at one time, but never actually put to use. I'm guessing the didn't work out. There was even talk about an all plastic transistor. I didn't have very high hopes for that. May ask which company(ies) you work for or have worked for? You seem to know more about the construction of semiconductors than anyone else I've met. I remember TO-3s were very commonly used for bi-polars in the 70s & 80s. |
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Gold Member Username: MagfanUSA Post Number: 1781 Registered: Oct-07 | Spent 30+ years in fab. A real fab-rat, if you will. I won't discuss WHO I've worked for, but I've made everything from low frequency quartz oscillators to sub-micron ICs and various proprietary DA / AD convertors for military use. Odd stuff like 7-bit. I think carbon in the form of Graphene will be the next BIG thing. Diamond substrates are available now. I suspect that even planar speaker membranes can be made from this stuff....and a fraction the thickness of Mylar. That'll give 'em incredible 'speed' and power handling...if it is a strong as the numbers indicate. I hope the conductors can be 'doped' into the material so no need for wires ribbon glued to the membrane. A ribbon tweeter? It'll happen. http://en.wikipedia.org/wiki/Graphene I may be possible to make Magnepan speakers in long rolls. Any material used WITH silicon in processing must be able to take the temperatures involved. Unless they are post-processing stuff like in packaging. The materials guys are working day and night on new stuff. That was why I about screamed when Bell Labs was sacked. They produced about a patent a day for 30 years ...or MORE. http://en.wikipedia.org/wiki/Bell_Labs They apparently are no longer doing what is called 'basic research'. Today people are trying to make better stuff or stuff for profit. People knew about semiconductors for a while before the first transistor (Bell Labs!) but it took from '47 to the 50's for the Nobel than another bunch of years before practical applications. |
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Silver Member Username: SuperjazzyjamesPost Number: 293 Registered: Oct-10 | I understand not wanting to id current and former employers. That's quite resume' though! |
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Silver Member Username: SuperjazzyjamesPost Number: 294 Registered: Oct-10 | I first became interested in how well semi-conductors handle heat when my grandfather's boss gave him a Fisher receiver with burned out chip amps. The heat sensor was located at the center of the shared heat sink. apparently the original owner liked to play music loud with 4 speakers going. As far as anyone can tell, the location and setting of the sensor were problematic since the unit went into protect mode when the chips were already fried! Helpful right? |
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Platinum Member Username: PlymouthCanada Post Number: 15429 Registered: Jan-08 | Super If you talk about STK's chips, these amplifiers was not too much reliable with a low impedance charge. |
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Silver Member Username: SuperjazzyjamesPost Number: 295 Registered: Oct-10 | I don't remember who made them Plymouth, they had 8 pins each (I think) and appeared to be nickle plated. If they were STKs, and STK chips were that sensitive to low impedance, that would be one more factor. They were screwed onto a heat sink with one heat sensor halfway between them. The pre-amp was great though. It made my experiments possible! I inherited the receiver when my grandfather died. I was always hoping he"d fix it and get speakers for it and that he and Grandma would play Christmas music through it when we'd come over on the holidays. I don't blame him for not wanting to spend the $100 for the 2 chips though. |