djk Posted March 22, 2005 Share Posted March 22, 2005 The 9Khz peak is over 15dB from 3Khz down on most units. http://www.atlas-soundolier.com/techLib/SLSheets/SL2.1551.PDF The peak is caused by the 1.5" diameter of the exit into the phase plug. The newer solder lug version, and the M version, have a two port phase plug that moves it to an even higher frequency. By itself, an inductor will not tame the peak. You must either use a 12dB roll-off as ALK does, or the 'P' trap. PWK used 230µH and 4µF on the later K55V to flatten the midrange in the 3Khz~6Khz region and cut it off steep above there (used with the 18dB tweeter network). Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted March 22, 2005 Share Posted March 22, 2005 My '62 networks are virtually identical to Michael's, mine are stamped C-22 and they are a 1000Hz-5000Hz crossover point based network. I just installed DeanG's Type B w/P's last night all Kimber Kapped, love the detail with them now. I prefer these new incarnations to the Type B's with the hand rolled Jensen PIO's that I had in there previously. I will post a review and some photos soon, now you guys have me worried that by some remote chance my really old K-55V's in them may or may not suffer from the glitch. I replaced the K-55V's in my '77 Khorns and '78 La Scala with the solder terminal versions some time ago. I wanted to leave the vintage Corns all original though. First impressions - man they sound awesome - the hash and grain is gone and they are really smooth! Now they complement the Khorns in the rear really well. All my networks are done now it is time to sit back and enjoy! Quote Link to comment Share on other sites More sharing options...
Dflip Posted March 22, 2005 Share Posted March 22, 2005 I would think that the 1974's would probably be B networks on the Cornwalls. A 2.0 uF, 4.0 uF capacitor and a 2.4 mHy inductor with a T2A autoformer. Many options are available for the simple replacement of the old caps with either Jensen PIO's, Hovland Musicaps, or the second tier of polypropylenes. The inductor can be replaced with a heavier gauge of wire (10 or 12) Solen solid wire which will help the bass end. Others can probably help you more with the P-trap idea if you are going to try it. Rope caulking the squawker is also a common suggestion to help soften up that horn. Quote Link to comment Share on other sites More sharing options...
Deang Posted March 22, 2005 Share Posted March 22, 2005 Michael, the addition of a single inductor makes it a first order filter. It means an electrical imposed cutoff on the squawker as opposed to an acoustical one (letting the squawker roll off naturally on it's own until it "runs out of gas". Al, can I play Angel's Advocate here? The resistor across taps 0 and 5 on the autotransformer -- what is the difference between putting it there, or at the amp's outputs, or the speaker's input terminals (it is after all, input to ground). Power is "wasted" to flatten the impedance -- I mean, that's what swamping resistors do. By adding it into the network, it's probably adding an additional 3 to 6db of insertion loss (as compared to the AA). Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 22, 2005 Share Posted March 22, 2005 Sorry for more questions guys, but I think I'm getting a better grasp on this xover stuff. Frz, so do you mean that my 63's have a 1000 Hz xover between bass and mid? Why have a 600 Hz horn then xover nearly an octave higher, in the vocal range no less. I consider this a waste of good driver and horn (unless it's a driver protection scheme, but couldn't we do that with a sharper slope?) I'm with you in terms of leaving our 'historic' systems alone for the most part, but have you at least replaced the caps? Dean, the 'order' of the xover is the slope, yes? I thought in terms of a hipass filter, that a simple capacitor was 1st order (6 dB) then adding the coil/autotransformer in parallel made it 2nd order (12 dB). Is this incorrect? And re the diff K55's, so the solder terminal units have the two-part phase plug that reduces the 9 kHz bump? Meaning that if you have the spring terminal units, you should make the 'p' trap or other xover mod for the upper squawker end? And what is a Jensen PlO? is it another type of cap? I understand that Hovland and Solan are highly thought of brand names. Is it worth the $$? Michael Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 22, 2005 Share Posted March 22, 2005 Dean, The swamping resistor I use has to go between the squawker filter and the K55 driver. It can be on either side of the transformer if the value is adjusted. It does NOT reduce efficiency becasue it only uses the power that is NOT used by the squawker driver. It is like saying that the right headlight on you car does not reduce the brightness of the left headlight. All the pair of lights do together is draw the "correct" amount of current at 12V to equal the right total load impedance. That of cours doesn't matter toa car battery, but does matter to an amplifier. Remember, R = E/I. In this case we want 8 Ohms so we parallel the transformed 16 Ohms K55 driver and a swamping resistor so that the pair draw the "correct" current to make R = E/I = 8 Ohms. Al K. Quote Link to comment Share on other sites More sharing options...
Dflip Posted March 22, 2005 Share Posted March 22, 2005 Jensen PIO capacitor Hovland MusiCap I would avoid the Solen's, they have not received to many positive reviews, except for the very large value caps, 68 uF where they are used due to their less expensive price. Hovlands would 6, 10 uF, plus and eight at over $40 US per cap. The Hovlands are brighter and provide more detail. The Jensen's provide good soundstage and do dull the squawker a bit, so it is a matter of choice. I have used both and the Jensens are in my B network at the moment. Another cap to look at include Auricap, less expensive than the Hovland or Jensen, but has a very good reputation. Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted March 22, 2005 Share Posted March 22, 2005 Michael, I installed all new networks from the ground up inside them. They are nice! I will be posting some photos of them installed and quick review this evening. Look for it! I put the 100% original networks in my closet and they will remain that way. If I ever sell the speakers I wanted to have the stock network and wiring. I updated all the internal wiring and added the gold plated crimp on spade lugs to make it real pretty to complement DeanO's work. My C-22 network had 1000-5000 on it which means to me the Xover points were 1000 and 5000. Dean's network changes those points if I am not mistaken so the woofer and midrange are not having to go as high anymore which to me means they will have to work less. They were immediately cleaner sounding, Dean do you condition the caps? DFlip don't forget the Kimbers, the Jensen PIO's sounded a little dull to me in my '62's but I love them in my La Scala! My Jensen's are silver. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 22, 2005 Share Posted March 22, 2005 Frz, yeeooch, how much did that set you back? I'll have 5 Cornies and my two Industrial LS to potentially do. Can't afford 7 x couple hundred bucks! I've seen some of these xovers go for several hundred dollars apiece. Don't get me wrong guys, they look like works of art, but is there REALLY that much sonic impact? I mean, you're not reinventing the mid driver, etc, so how much difference can it make? I realize that the electronics are somewhat dated and PWK's theories may have scrimped for the sake of marketability and profitablity but geesh! Price wise, how much are we talking for the different approaches, knowing that BEC's is to repair/replace items on the original boards and the other approaches may be completely new parts? Thanks guys, I really am an interested buyer here- so SELL ME! Michael Quote Link to comment Share on other sites More sharing options...
sfogg Posted March 22, 2005 Share Posted March 22, 2005 "The 9Khz peak is over 15dB from 3Khz down on most units." More like 5dB on the one I tested.... Shawn Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted March 22, 2005 Share Posted March 22, 2005 Yep, I remember that graph Shawn, you posted that awhile back showing the 9Khz glitch. Michael, best to contact Dean or Bob for pricing info each situation is different. I did all my networks over a period of time so it was not as much of a drain on the pocketbook. Trust me it makes a big difference, you wont have to struggle to hear the difference at all! It will be immediately apparent to you. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 22, 2005 Share Posted March 22, 2005 "Bob, so then does my B-1 pictured here need to have it's caps changed out? I take it those are the two cans bolted to the board. Or could these components be tested individually to see if they're still in spec? For some reason, I would like to keep the 63's as stock as possible." Michael, Yes, those caps need changing. I like to keep things stock also, but would not hesitate when the spark plugs in my 1968 T-bird need changing. Bob Crites Quote Link to comment Share on other sites More sharing options...
Deang Posted March 22, 2005 Share Posted March 22, 2005 Dean, the 'order' of the xover is the slope, yes? I thought in terms of a hipass filter, that a simple capacitor was 1st order (6 dB) then adding the coil/autotransformer in parallel made it 2nd order (12 dB). Is this incorrect? A cap in series with a coil forms a first order bandpass. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 22, 2005 Share Posted March 22, 2005 Thanks for the smilie Dean, I thought I was getting more confused than normal. Okay Bob, pm me that shipping address one more time. Do I need to do anything with my single B3 network for now. It DOES NOT have the oil/paper type caps. All solder joints look to be in good shape. Michael Quote Link to comment Share on other sites More sharing options...
BEC Posted March 22, 2005 Share Posted March 22, 2005 Michael, I don't have a lot of experience on how good the original caps in a B3 might be. Still sort of hold to the idea that 20 years for the caps should be considered a full and productive life. After that just say a few words over them (if you like) an toss them. Bob P. S. you have a PM Quote Link to comment Share on other sites More sharing options...
Deang Posted March 22, 2005 Share Posted March 22, 2005 The swamping resistor I use has to go between the squawker filter and the K55 driver. Not the 5.6 ohm value across the squawker -- I was thinking of the 10 ohm resistor that sits between taps 5 and 0. It's basically the same as if it was sitting between input pos and input neg (with the exception of the 40uF cap), Yes? It can be on either side of the transformer if the value is adjusted. It does NOT reduce efficiency because it only uses the power that is NOT used by the squawker driver. It is like saying that the right headlight on you car does not reduce the brightness of the left headlight. All the pair of lights do together is draw the "correct" amount of current at 12V to equal the right total load impedance. That of course doesn't matter to a car battery, but does matter to an amplifier. Remember, R = E/I. In this case we want 8 Ohms so we parallel the transformed 16 Ohms K55 driver and a swamping resistor so that the pair draw the "correct" current to make R = E/I = 8 Ohms. I will have to think about this one. I thought they repealed Ohm's Law while I was still in High School. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 22, 2005 Share Posted March 22, 2005 Dean, Nope! They didn't repeal Ohms law. They just expanded it so that now it works for AC too! Al K. Quote Link to comment Share on other sites More sharing options...
Klewless Posted March 22, 2005 Share Posted March 22, 2005 OH MAN, Not another AC/DC law! Darn that ohm guy. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 22, 2005 Share Posted March 22, 2005 Man, Don't 'ya know all this started with a little AD-DC guy doing his yoga exercisies while chanting "Ohm.. Ohm... Ohm".... (Now who's Klewless?) Al K. Quote Link to comment Share on other sites More sharing options...
jwc Posted March 22, 2005 Share Posted March 22, 2005 Al, Speaking of Ohm. Is it true the ALK networks will work with any combination of drivers whether they are 4,8 or 16 ohm. I wondered how people are integrating the Altec 902 8b with your networks when the K55 is 16 ohm. Will different impedences work with your ALK B networks and the ES networks? For example, say a cornwall with a K77, 902 8b, K33E? Thanks as always jc Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.