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Neal K

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Posts posted by Neal K

  1. 2 hours ago, RTally said:

    Does your Seventeen match this schematic?

    KLH 17.jpg

    It is best to replace the caps with like-for-like values. Redesigning a crossover is not a trivial task. The KLH 17 crossover is not a simple first order filter. It is a 3x cascaded, first order filter that has a switchable FR for the tweeter. 

    Each position of the switch has a different contour for the tweeter FR. The 3 ohm resistors in parallel with the 2 uF caps allow a portion of the signal to bypass the cap and has the effect of lowering the attenuation at higher frequencies. The frequency at which the attenuation changes and the amount of attenuation is a function of the switch position. 

    I haven't opened it up yet. But it's a pair in very good shape and i don't think it's been modified or opened up. It's just a good idea to replace electrolytic capacitors after a half a century, god knows what they measure out at. I think I'll order some polypropylene caps from PE or Madisound. Maybe MDL caps at 12, 10, and 8. And 2 pairs of 2 mfd polys. The nominal crossover frequency is 1500 hz. I should probably not use anything higher than the 8 mfd series, as it is already about an octave lower than most of todays designs. I don't drive them too hard volume wise, I'd rather have the transient response and clean peaks with clean power. It's only a 6db/octave slope. Maybe I'll just order a pair of Clarity 8 mfd. I get a kick out of the "Capacitor freaks" who pay more for caps than they paid for the pair of speakers in the first place. I wonder if Solen and Mundorf pay these people. It is really funny. It's just an unusual circuit design with the 2 and the 8. I'm going to do a lot of listening then hard wire it either with or without resistors. If I do decide to use them I'll get the Mundorf metal oxide ones in an L shape. But there's nothing in life like real clean bass. Listening to classical or a Moog bass, it makes a difference that no 5 inch little box speaker can match. The vibes move the floor and walls and envelopes you in sound, and that is what it's all about, right? That's why were all here. Clean bass.  

     

     

  2. Hello everyone,

      I am looking at a pair of seventeen that look to be in good shape. It's great that the surrounds are cloth.

    They look inverted the way they are on the driver. My question is regarding the wiring to the filter. I've looked at it here and the one for the AR

    model six. They have 3 positions. It looks like in 2 of the positions the signal goes thru the 2 then the 8 mfd cap. I've never understood the thinking behind

    how it's wired. it looks like some of the signal goes thru both, and some goes thru just the 8. It's contouring thee top octave I guess. Can someone enlighten me because I'm going to grab them and replace the caps. No inductor the 10 inch rolls of after 1500. There is an 8 and one of those 2 in one job's. I'm thinking I probably will just listen and put in a single 10 mfd and possibly an L-pad. have to listen first. So what is the deal with the funny wiring? Thank's

  3. OK. duh. Right after I posted my comments, I scrolled down on the home page and holy cow batman. Duh. I really should get my facts straight. I mean where I said there should be more than just AR, KLH, and Advent. Genesis is right there! Duh. And thanks genek and RTally for the info about Villchur.

  4. Hi all, 

    Is everyone making the most of the summer? That is, when it isn't raining! I was thinking recently about getting a new pair of speakers. That thought led to the next thought; there are many acoustic suspension speakers out there and some of them sound pretty good. I can share one example. In 1977 after much listening and comparing I bought a pair of genesis ll's. I am not sure if that is correct sp but you know the one, one inch inverted dome and eight inch mid/woofer with a ten inch passive radiator. I realize that this speaker is closer to a ported design, but the box is sealed. That is a great speaker for the money. it's probably a good speaker at any price. I kept those for over 20 years and two refoaming jobs. The firsst one was due to me agreeing to cat sit my kitty for my brother. Big mistake. Like most of you probably do I listen without the grills on. Yep you guessed it. The bloody cat used the eight inch and passive as claw sharpening  tree. I freaked out when I was it. Long time ago, so long that it was refoamed with foam. and about 20 years later they started to crumble and tear like all foam surrounds do. But the point is, that speaker put put sound from approx 38 hz to 18 k. And with respectable dispersion and transient response. I got a lot of mileage out of them. Maybe it isn't just the designs but the time period most of the classic speakers were built in. You do not see cabinets built out of 3/4 inch or 7/16 MDF today. Not even close. A lot of what I see is quarter inch at best and foam sound control seems to be optional. But I know there are speakers out there the are made from well designed drivers, components and wood or extruded plastic. One that comes to mind is the guy up in NH, Huh Powell. I only know about him because he repairs and sells replacement drivers for Genesis, EPI, and a few others brands. He makes a eight inch two way sealed box with an aluminum inverted dome that is a pretty decent speaker and it's priced very reasonably. One last thought before I sign off. Edgar Villchur should have gotten a Nobel for inventing the acoustic suspension speaker and not patenting it. And all these great speakers were born. Well that's my 2 cent's Be well, enjoy the summer while it's here and listen to some good music.        

     

  5. On 12/22/2007 at 11:06 AM, RoyC said:

    This is one of the most sensible capacitor discussions I have read in a long time (other than the "guru" part...thanks Kent :-)!

    If you guys want to split the difference, you can try low value mylar caps on the tweeters (maybe even the mids) and electrolytics for high values. Many commercial speaker companies have done this.

    Mylars, like electrolytics, but less so, appear to have a bit more esr than polys do, so don't feel compelled to tweak the circuit if you are not in the mood to do so. They are relatively inexpensive, and easily obtained from Madisound (Carli branded and "surplus"..the 3uf surplus caps are very good!). The main advantage of this approach is that film caps are very stable for the long term, and that degradation issues are more likely to be bothersome in the upper frequencies. Madisound also sells Bennic electrolytic caps, which have a good reputation.

    Roy

    Hi guys I am new here. I have been restoring, modifying, or building speakers a few years now. I discovered PE and Madisound, which are both great. In looking for information on driver sand crossover schematics I have come across some of these "Boutique" crossover sites and threads. What substances are these guys on? They talk about the aural qualities of capacitors as though they were drivers! And the crazy prices of some of these "Audiophile" capacitors is kind of nutty. i wanted to post a question: does anybody here realize that these components BLOCK or FILTER frequencies. You are not supposed to hear them! Distortion I can understand. But given that the majority of serious professional speaker and monitor designers and makes use electrolytics, does this not suggest something? Are these threads just fronts for the designers, builders and marketers of these crazy priced components? I figure that has to be it. Or there are more delusional people in the world than I thought?  

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