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Everything posted by PrestonTom

  1. VDS, Have you read Toole's book. Some of it is subtle and needs to studied. What did you think of his overall approach and conclusions? It is a worthwhile reference but the "what and why" is not easily summarized. Good luck, -Tom
  2. You are thinking of someone else. I tend to be old school when it comes to electronics
  3. First, take Edgar's advice. It is quick and simple and can help pinpoint the problem Although, didn't "we" already eliminate this problem a few days ago? BTW, has the sloppy grounding on the "Rawson" Amplifier been cleaned up yet?
  4. Since the F3 is a Rawson build, I am very suspicious. Let's hope this mess can get cleaned up.
  5. VDS: Please clarify a couple of things. Is the Pass amp a DIY or a factory version (what I am getting at is whether the input grounds are directly or indirectly electrically connected to the amplifier chassis). The shield on the RCA side of the cable is electrically connected to Pin 1 on the XLR. However is the mechanical connection at the RCA side or the XLR side (or both). The reason I ask (and this is a remote possibility) is whether the the "third wire" is not connected on one end then it could be acting like an antenna and picking up junk (not a technical term). In either case "fixing" the cable can help things (whether it is ferrite acting as a filter, or a transformer isolating any small potential difference (voltage)). This is why I say this is ultimately a cable issue and not an amplifier issue. The reason some of us are having difficulties is that bad cabling usually results in low frequency junk (hum etc). Your problem is a bit different. As an anecdote, I used to work in auditory labs (science kind and not the recording kind ...). Mixing balanced and unbalanced equipment was always a nagging problem (not every time, but occasionally). We would all come through the set up when there was a problem and frantically swap cables, power cords, toggle "ground float switches" etc, etc. Eventually, the circuit would quiet down (after going through an endless combination of wire / equipment swapping) and someone would proclaim: "see I told you so .... it was a ground loop" (although they never actually pin-pointed the culprit). BTW, if you look at the schematic of what the Jensen ISO unit is, you can mimic it for less money although it won't be packaged in a nice box (Cinemag will have the appropriate transformers for about half the price). These boxes are frequently used and have been even in the old days. Good luck, -Tom
  6. Absolutely not . I believe it is a cable issue. This is not uncommon
  7. Yes, you will need four channels of amplification. My suggestion was to simply use what you have on hand or what you can either borrow, or pick up for cheap on Craigslist. My store room may look different than yours, Over the years I have accumulated quite a bit of gear that is now just laying around. I sometimes assume that others have my same bad habits. -Tom
  8. Honestly, you are going to have a full plate when the Jubilees arrive. Personally, I would concentrate on getting them set up in your room and adjusting & re-adjusting their locations and the the location of the seating area. The issue of amplifiers (within reason), will simply be "frosting on the cake" and not really a major concern. Get used to the Jubilee sound first and then go from there. Good luck, -Tom
  9. Well, you want an amp that does not have much background hiss or noise. I have been happy with the old Adcom GFA 5x5 amplifiers (535, 545, 555). They will be at least 3 decades old, that may or may not be a concern for you. They are on Craigslist all the time and selling at reasonable prices. Good luck, -Tom
  10. Well it looks like there is progress. This is not the first time someone has had problems going from balanced to unbalanced, although it is curious that that the "junk" coming through is at such a high frequency. I assume the cable is XLR at one end and RCA at the other (IOW, no additional connectors added to an otherwise three wire cable). This probably is not the problem, but have you measured whether the pin 1 and pin 3 on the XLR side side of the cable are electrically tied together ?
  11. Come on guys ... this is just a guessing game at this point. The OP needs to be more articulate by what he means by "whistling". Please be more specific, otherwise we are only guessing and any advice you get will be very suspect.
  12. At this point, one could say "Eureka", but that is such an obvious joke .....
  13. Styrofoam pellets are probably preferred - certainly safer
  14. You said the K-402's have cracks in them. Could you show us photos detailing these cracks?
  15. There are a number of things that don't add up here. 1) Crossovers seldom "just die" unless they were heavily abused. Connectors, come loose etc, but I would first make sure the the problem was the crossover - there are logical ways to do that. You or a friend will need to have an inexpensive volt meter at the very least. 2) there is really no such thing as a substandard crossover (I think you mean some sort of generic crossover. I am guessing). If that is the case, then of course they don't sound very good. 3) First make sure all the drivers are working and the signal is getting through. 4) use the "good crossover" and have a friend order replacement parts from Parts Express or Madison etc (resistors, capacitors, fuses). If there is an auto former on these (and I don't know if there is), I hope you still have that part since they are difficult to replace with the correct one. Any auto former or inductor should probably be okay. These may have one of the Klipsch protection circuits on it (they had a silly name IIRC). Those will not be necessary. 5) before you take anyone's advice on this (including my own). A) let us know specifically how you determined that the problem was the crossover and B) take a picture of the cabinet and several pictures of the crossover. Any advice without these two points of information is likely to misguided. Don't worry it can be fixed, -Tom
  16. Yes, I also got a deal on mine. They simply don't come up on the used market all that often
  17. Well you need to start with your requirements. Are you willing to use a pro amplifier that has DSP internally on the front end? Do you require a digital input for DSP? Are you putting the (analog) attenuation after the DAC from the DSP box (this means the not only the signal but any residual hiss / noise is also being attenuated)? How sensitive are you to a low price? Do you have any desire to use FIR filters and not just IIR filters? This is just a start.
  18. Just on a cautionary note. Do you think the 2050's that Klipsch buys (and perhaps modifies) are same quality as the ones that Parts Express buys? Do you think that Klipsch might require certain modifications on the 2050's when they buy them? Something to consider.
  19. Actually, there are many choices.
  20. Roy, I would hide. They may come and want to grind up your bones.
  21. I would give zero weight to the number posts that someone has. There is one guy on the forum that probably racks up 2000 posts in two weeks. Do the arithmetic, do you think those are thoughtful comments he is making?
  22. Well that is their decision on how they want to advertise these. Please keep in mind that the first batch of the "new" Jubilees may be a special anniversary edition (special wrapping etc on a limited run). What the "regular price" may be (after the "special edition") is still unknown to the public. Keep in mind that I am a cheap son of a gun and price does matter!
  23. In the past, some of the manufacturers(for the pro sound or commercial divisions) like JBL or Klipsch would specify whether the measure was made free-field or half space and also what the -6dB or -10 dB response was so the installer or end user could get a idea about was their freq response was and what might be gained by placement in a corner or near a wall. I do not see that here. Please remember that these kinds of details lean toward advertising rather than technical specifications. All the manufactures do this.
  24. I found this over at one of the other audio forums. Please note that it is stamped "preliminary". As far as I understand things, availability and pricing are not yet set in stone. The rumor is that the price is high, possibly a bit more than 4x the cost of the current production Jubilee, however this includes the cosmetics and the DSP crossover. What is of note: 1) it is expensive, 2) the footprint is larger (no longer comparable to the current Jubilee or Klipschorn), 3) low frequency extends to a lower frequency (although no qualifiers are mentioned i.e., required placement or +/- values), 4) bass bin is a single woofer & is vented & horn loaded 5) Crossover point is lower, 5) new tweeter driver, 6) cosmetics are fairly industrial looking so it is compatible with some decors, but probably not the majority of living rooms. My personal view, it is probably best to withhold judgement until the product is finalized and actually shipping. Interesting times, -Tom
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