Al Klappenberger Posted January 19, 2005 Share Posted January 19, 2005 RATS! I did it again! The plot of the AL I just put up is also from an 8 Ohms source! Anyhow, it looks a lot like the AK-3 from a .1 ohm source but with a little hook at the low frequency. It's basically more of the same though. Al K. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 Thanks for the plots Al, very cool. It looks like the trap works in the modded AA, though I wish that first transitition was a little smoother. Well, I guess it's a budget mod, so you get budget results. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 20, 2005 Share Posted January 20, 2005 Dean, That AA mod really should not be called a "trap". That would be a configuration like the "P-trap". It would be an L and a C connected together and in sereis with the squawker. This is in the form of a lowpass filter. The parts selection gives a boot at one point becasue of an impedance mismatch. I don't know if that was intentional or not. That's why I will leave it up to you if it's a good thing or not! Al K. Quote Link to comment Share on other sites More sharing options...
Parrot Posted January 20, 2005 Share Posted January 20, 2005 Can someone offer some commentary on what these graphs mean, in English? Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 20, 2005 Share Posted January 20, 2005 ---------------- On 1/20/2005 9:20:42 AM paulieparrot wrote: Can someone offer some commentary on what these graphs mean, in English? ---------------- I'll second that. If this was a perfect world what would the gragh look like. To me the type A and AA look the best. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 Paul, I don't think math can be explained in English -- I'm serious. As soon as Al starts explaining something to me in English -- it just turns into math again!! Craig, remember, Al is looking through the squawker. Since the A and AA don't have a cutoff, they stretch out --. Check out the ESN, where Al slams it off hard -- and weeeeeee. Al, of course, not "a trap" -- I knew that, but I've had traps on the brain, and driving on very little sleep these days. So Al, what does the "P-trap" look like from the computer (.1mh coil/3uf cap in parallel, wired in series between the positive terminal of the K-55-V and common)? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 20, 2005 Share Posted January 20, 2005 Dean, Here's the "AA" with the "P Trap" included. It generates a big dip at 9.1 KHz. This is the point where the early K55V driver (with the puch-pin connections) comes back generating a sound that clashes with the tweeter. There is noting in the AA to stop it otherwise. The AA (and all the other netwroks ever used in the Heritage series) has nothing to stop it. They depend on the K55 driver pooping out naturally at 6000 Hz. Note that my "type A" attenuates 9 Khz by about 8 dB. The "P trap" and my ES netwroks nail it! The trap is connected between tap 4 of the transformer and the + terminal of the K55. It's in sereis, not across the k55. Al K. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 20, 2005 Share Posted January 20, 2005 Al, Would it be worth while to add a "P" trap to your "A" networks? If so what would be the values? How about adding 136uF+/- across the woofer? Rick Quote Link to comment Share on other sites More sharing options...
D0N Posted January 20, 2005 Share Posted January 20, 2005 I gotta ask a possibly dumb question... why are there coils of wires in a x-over? What if you skipped the 10' long wire and used a 2" piece? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 20, 2005 Share Posted January 20, 2005 Rick, Yes, if you have the early K55V with the push-pin connections with the "A" netwrok the P-trap may help you. It will depend on if your particular K55 has the 9 KHz glitch or not. I don't think all of them have it. Don, All wire has inductance. If you wind it into the form of a coil the inductance is multiplied. The more wire the more inductance for a given coil. Finer wire also give more inductance, and more DCR too! If you have to ask what "inductance" is you need to go to the library and take out a book on basic electricity. It's hard to explain in a few words, but to oversimplify, it's the effect on the current through a wire casued by changes in the magnetic field casued by changes in the current itself. That effect is exactly opposite to the current that casued it. Thus the term "back EMF". The more inductance the more back EMF and the more the inductor opposes changes in current through it. A good example is the spark coil in and older automibile engine. The current through the coil is shut off abruptly when the points open. The magnetic filed collapses and causes a huge voltage that tries to keep that current flowing. Zap! Al K. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 Will the real "trap" please stand up? From the archives: "I think the P-trap config. you saw was a 0.25mH inductor (after the stepdown trans) in series with the squawker + with a 4 uF cap in parallel to the common." "This crossover has no high cutoff for the mid. it depends on the acoustic response of the Atlas driver. It will die at 6k but most come back at 9k. This causes a harsh sound people think is caused by the horn. A simple trap will cure the problem . Parallel a .1 mh. coil and a 3mf. cap. Connect this combination in series with the + terminal of the mid driver" . "Take one twisted cap/coil combo end, and connect with the + terminal of the squawker. Connect the other twisted end to the wire you first removed from the squawker + terminal." Al's final note on this corresponds to the statement above. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 Now that we have that one sorted out for the most part -- let's work on this one! LOL. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 20, 2005 Share Posted January 20, 2005 Dean, NO! The P trap drawing above is WRONG! That connection would pass 9 KHz only and reject everything else. It is SERIES resonent. You want PARALLEL resonance in sereis to reject 9 KHz and pass everything else!! If you look at squawker filter in John's scematic, it is series resonant. The two parts are connected in sereis with the primary side of the transformer. They will pass the midrange only and reject everything else. Resonance equals 1 /(2 * pi * sqrt(L * C)) 40 uFd and .2 mHy = 1 /(6.28 * sqrt(0.2e-3 * 40e-12)) = 1779 Hz. It should be resonant to geometric center of squawker passband: sqrt(400 * 6000) = 1549 Hz. Close enough! BTW: The ratio of L to C determines the bandwidth. There are an infinite number of L and C combinations that will resonate at 1779 Hz. Al K. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 Thinking one thing, drawing another. I better stay out of the workroom today. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 20, 2005 Share Posted January 20, 2005 Dean, Now you got it! We duplicated efforts. I attached the "schematic" version. Al K. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 John's filter seems to sit squarely between the ALK and the Type A. I'm to that point where I simply have to suck it up, sell something off, and get some LaScalas or Belles in here. Quote Link to comment Share on other sites More sharing options...
Parrot Posted January 20, 2005 Share Posted January 20, 2005 Is this a hint that you're getting ready to sell your VAC amp? Quote Link to comment Share on other sites More sharing options...
Deang Posted January 20, 2005 Author Share Posted January 20, 2005 No. Probably a handgun or two. The VAC is staying for the time being. I'm sure after I try one of those $100 digital amps -- it'll be on Audiogon faster than you can say "zero and one". Quote Link to comment Share on other sites More sharing options...
Parrot Posted January 20, 2005 Share Posted January 20, 2005 LOL! Quote Link to comment Share on other sites More sharing options...
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