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WMcD

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Everything posted by WMcD

  1. I believe this is pretty normal. Part is based on m,y building a piece from The Bartley Collenction, Now out of business. You also should hunt around the internet. Cherry is like a lot of hardwood in that in a raw state as sawed, the wood is pretty much beigh (light tan). As it is exposed to the atmosphere it changes toward a rust color over, say, three years, by oxidation. Apparently this is not prevented by a "clear"cover of varnish or shellac. Though these covers always incease contrast and darken the wood somewhat. One problem for sellers of the solid wood or veneers is that buyers want that rust color in the wood as sold. The solution is that they will force the process by applying a lye solution or by applying a dye or stain. The bottom line to the analysis is that cherry will tend toward rust but what you buy is probly a somewhat dyed beigh cherry which changes toward rust even moreso. WMcD
  2. I had to check Walgreens' site for five days and then got appointmments for Pfizer first and second. The first was just last Thursday at one of the few Wags in the Loop which was still open. The second will be in four weeks up north of Wrigley Field. No reaction --- but I'm pretty sure I had Covid a year ago at the end of January which might have been a factor. I asked for and got it in the left arm figuring that if there were a reaction it would be better to have it in the non-dominant arm/hand. YMMV. WMcD
  3. Good idea. When a ham passes away his name is followed by "(SK)" for "silent key" Maybe we could use SH for silent horn. WMcD
  4. I just looked around the Internet and see that the MC2105 has a damping factor of 13. I don't see any info on what tap was used or what load was assumed. Assuming an 8 ohm load this equates to an output impedance of 0.62 ohms. = 8/13. This does not mean that you should put a load on it of 0.62 ohms. In conclusion though, if you have a speaker which varies between 4 ohms and up, you should use the 4 ohm tap.
  5. Here is a graph of the Cornwall input electrical impedance. Putting a single value on the impedance is not possible because it varies with frequency. This is from the Belgian Audio Society test and I suspect it is on what we know as a "Cornwall" rather than a Cornwall II. I have not seen any factory equivalent. It is important that this goes down very low and probably to 4 ohms. The Heyser review of the Klipschorn is at least consistent. And likely the K-33 has a voice coil resistance of 3.8 ohms or so. Klipsch's notation that their speakers are "8 ohm compatible" seems to only be saying that the owner can hook them up to an amp which says it is fit for 8 ohm loads. Very generally the output impedance of a transistor is lower than 1 ohm despite what the autotransformer taps say. This is not widely stated by manufacturers but at least in some instances the damping factor is given and ouput impedance can be calculated from this. Also, it is true that Jacobi's lww is good in some circumstances but IMHO it is at best difficult to apply here. For exaple, if your amp does have a 0.1 ohm output impedance we'd be looking for 0.1 ohm speakers. One this which is generally recognized is that audio amps put out less distortion when driving a load which is high in impedance. Distortion is lower when you attach an 8 ohm load to a 4 ohm tap. Another matter is that background hum and noise is lower in magnitude when the transformer is not stepping up their level by the use of e.g. the 16 ohm tap. WMcD
  6. There was a story of PWK giving a demo with Heresy's placed in front of KHorns with no announcement of which would be playing. He'd start the demo Isecretly playing only the Heresy's which everyone (?) thought sounded very good. Then he'd say, "Oh, let's hear the KHorns (alone)" which everone thought sounded very good and a bit better -- but surprizingly not startling so. What program was used I don't know.
  7. Do the speaker boxes have serial number / model number labels on the back and can you take photos. That info might provide some background. Bacek has a good guess IMHO. Wouldn't it be something if they are different models.
  8. Just to continue my earlier, if overly long post . . . The "ramps also have a sharp angle which is difficult to cut. So I just used a less steep angle on that end of the ramp and use a 1/4 round piece of trim. A 3/4 x 3/4 piece would do as well. I also did use "reflectors" as shown in the Peavy. I don't think they reflect but should even out the cross section a bit going round the bend. Let me again suggest the form factor of the LSII. This is because the bass bin is about a 2' cube. But importantly, all the vertically oriented elements should stand between the upper and lower square plates. Therefore it is important that they all be the same length (height) but an identical error is not of consequence. You can rip a 4' x 8' and make sure the cut is arallel to the edge but not really worry about the kerf. WMcD
  9. I don't quite understand. You say the project "demands" maple gray. But then it seems like you may want to change the color. From what I see on the internet the maple is bleached and then dyed gray. When you say "finish" are you talking about the somewhat clear varnish or lacquer that goes on top of a dyed or stained piece of wood. Most will acentuate the grain or pattern in the wood. What is the goal? For that matter, what are you starting with. WMcD
  10. You should use the search function on the forum to find LaScala plans. You'll see the option to search for content with all words rather than any word. You'll see several plans and it is worth taking a look at all available . Among the results is my post with the plans by HDBR. I can vouch they are absolutely accurate to the extent I used the info to make full size drawings. I suggest you do the same. I know grid paper of that size is expensive. Let me point out that some Christmas wrap has a 1" x 1" grid on the back. Hallmark? There is video someplace (someone will help, please) showing the factory construntion of an LSII. It is make of 1" MDF. If you like the separate "top-hat you figure that out easily. Also, you'll note the dog-house (shaped like that and the woofer lives there!!!) is built up separately with "home plate shaped elements at the top and bottom and the assembly is slided into the cubic box. Otherwise it is a bear to get everything lined up. Let me suggest you don't try to make the sharply poiinted front of the doghouse because that cut is very diffiult. Rather, replace it with a 1.5 inch wide board similar to the Belle. I would not use MDF in the weather though if painted with boat paint everywhere on normal 3/4" ply you might be okay without marine plywood which is expensive. There is the theory that the sides resonate and at least some builders put a brace between the wall of the doghouse and the wall of the cubic box. 1.5" wide should do. Of course critters will love to build a nest in them and you should consider metal screening as necessary. Those braces could be put to use in this aspect. WMcD
  11. You are asking about "velocity factor." https://en.wikipedia.org/wiki/Velocity_factor WMcD
  12. I'm glad that worked for you. I've been looking for some diabolically evil project to which to apply this phenomenon. MMMmmm. Haven't found one. Smile. WMcD
  13. I'm pretty much with Randy. There was a writer for a big automobile magazine long ago. He wrote that people ask him (he being an 'expert') what car they should buy. He said he tells them Honda. He explained that this was because with a Honda the person would least likely to come back and say they're unhappy even though it even though there might be better cars for their specific, and unpredicatble, situation and price point. You can't go wrong with a CW variation. If you can find them on the used market, the Forte II, Quartet, and Chorus II are magnificent. Good bass with the passive raditor and the terrific tractrix midrange horn. WMcD A
  14. Ha. IIRC there was an article in QST long ago describing corillaries to Edsel Murphy's laws. It was that units of measures given will always be in something odd. Velocity will be in furlongs per fortnight. I very much appreciate you bringing it to mind. WMcD
  15. Good to see you Larry C.
  16. Be careful. I suspect the HIII has a second order crossover for the woofer. If so, when you remove the connection to the woofer the crossover will form a series LC circuit to ground (i.e. across the input terminal). This will create a short circuit at about the crossover frequency. Damage to the L and C is certainly possible. I think of this tip from a moderator here long ago. Independent of that, I read about a train wreck in a non-Klipsch unit pro unit where a bass driver was found blown, the cross over was found foblown, and the amp was found blown. I suspect what happened was that the woofer was driven to destruction and was an open circuit and this caused the LC short. Then it was a race between whether the crossover components burned out from taking all that currect, or the amp was blown from the effective short circuit. (I suppose the coil could overheat causing a fire though I'm not sure.) Maybe someone can give advice on electrically disconnecting the LC, I suppose you could replace the woofer connection with a dummy load resistor of appropriate rating. However, that could heat up and cause a fire in the box. "Let's be careful out there." per Sgt. Phil Esterhaus WMcD
  17. Yes. Any anomoly is potentially dangerous. Have a licensed electrician take a look at it. WMcD
  18. I believe there was a Cornwall which was meant to be situated landscape or portrate. Neither the mid nor the tweeter were at the midline. Also there is something with a K-1000 midrange. Eventually it was superceded with what was initially called a Cornwall II. This had the K-600 mid like you see, the woofer, mid and tweeter were at the midline and it was presented as a portrate orientation speaker. Woofer near the floor. Eventually the "II" got dropped. This is probably why you see II on the spec sheet. But then there was a switch to plastic tweeter and mid and that was called the Cornwall II. Woofer moved up. The above might have so errors but close. WMcD
  19. Go to HD or Lowes and see what you can find that is not made in China except maybe lumber and paint.
  20. I highly recommend a temperature contolled (not variable temperature) soldering station. About $100. I have a Weller but Hakko is also recommended by by others. Over the years I have used a half dozen lower priced irons and I consider them dangerous for projects because of the potential to over heating or under heating. When you buy a kit, ask the manufacturer whether I'm correct. WMcD
  21. I believe this thread has drifted off course. Let me use small chunks of information. Sorry if it simplistic. Ya gotta understand the basics though. Sorry if the following is too simple and complicated at the same time. It is very possible that the tweeter is burned out. This is to say the wire windings have melted in a small section. The wire in the coil is finer than a human hair. The tweeter is capable of absorbing only about 2 to 5 watts continuous power despite specs that the system as a whole will take 100 watts. The mid driver might take 40 and the woofer 100 watts. Know that you don't have to have done anything very naughty to blow a tweeter. The tweeter wire is wound around a tube which is mechanically connected to the diaphragm. This is perhaps why people say the diaphragem is damaged. Essentially this is true of all drivers. This is winding is called the "voice coil." Voice coils sit in a magnetic field caused b the permanet magnet of the speaker. Current through the voice coil makes a magnetic field which pushes and pulls with force to move the diaphragm. The moving diaphragm makes the audible music. It is a bit more complicate than grade school of winding wire around a nail and picking up paper clips but that is the general idea. We want to test whether the coil has melted in a section and thus causing an open circuit. If no complete circuit, no current flow, no magnetic force, no movement of the diapragm and no music. But there could be a loose electrical connecton. About which more later. We are though trying to determine what is going on deep within the tweeter at a microscopic level by using a multimeter (ohm meter) connected to feed wires. Testing or listening for acoustic output is well done with a listening tube. However. You should know that these tweeters as filtered by the crossover or not really sound tinny and that is because music above 3000 Hz sound like that. Testing electrically is the most classic and reliable when a burned out voice coil is suspected. Use an ohm meter. which is part of a multimeter. This is really sending a direct current or zero Hertz signal to whatever is connected to the ohm meter probes. This may seem strange. We are testing a speaker by feeding a 0 Hz signal to determine whether it works at 3000 Hz and above. Actually the ohm meter is just detecting whether there is an electical path free of gap(s) in the wire. We actually detect the d.c. (direct current (zero Hz) resistance of the coil. This is usually about 5 ohms, 8 or 10 ohms is good too. A burned out winding measures "infinite ohms" which is what is shown on the diplay when the probes are not touched together. Maybe OL on the digital display. Older and newer meters will show 'infinite in their own way. Actual electrical testing. You should go to the crossover screw down teminals. Turn the amp off of course. The two wires connected to the tweeter should be seen and please note which wire (red stipe and another not). goes where. Take a picture or make a drawing. Disconnet both (not technically necessary but lets keep things simple). It is a matter of backing off the screws about a half turn. Righty tighty, lefty loosy. The "spade lug" (U shaped) should come free from under the screw head. I see no reason to mess aound with the tweeter driver end and that end is usually soldered. Now, connect or hold the ohmmeter probes to those two wires / spade lugs. If the voice coil is good, you will see on the meter a reading of 5 to 10 ohms or like that. Also you will hear a mild scratching sound from the tweeter. This sound is because the meter, through the probes, is sending a little current into the tweeter. The tweeter is trying to make a bit of music. A good sign that is can make music. OTOH: You may well find that the meter is showing OL still and there is no scratching sound. That is just about proof positive thatthe voice coil is blown, ie melted. Note: Sometimes over age the screw down connection at the crossover has corroded or loosened. Just snugging up the screw will cure that. Do it for all the screws while you're in there. There is some traffic above which is showing the measurement of the overall speaker "impedance" at the input terminal to a driver or box by the constant current technique. While intersting it is certainly not necessary to determine whether you've got a blown tweeter. Sorry if I've said too much or too litle. WMcD How to test acoustically? Yes, the improvised stethoscope with a paper towel roller works.
  22. Yup: As fathers have passed down to their sons for centuries, Righty tighty lefty loosy. Liquid Wrench gets good reviews. I would put the assembly with the big end on a table and squirt some in there. Wait overnight. Are these the aluminum horns? Perhaps the aluminum corroded a bit.
  23. Please consult a professional. These are potentially lethal insects unless they are honey bees. You're being nice to think about relocating the hive but this is like relocating a nest of rattle snakes. I was stung just below my right eye by a yellowjacket when I was young. Maybe I had tried to brush it away but they are agressive. My face was like pumpkin. Had it gotten to my eye I'd probably have lost it. You can read plenty of stuff on the internet. There is already a chance a queen has established another hive near you. The reproductive rate is phenomenal. Listen to Jeff (thanks Jeff). These are killers. WMcD
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