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mikebse2a3

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Everything posted by mikebse2a3

  1. page two of the article for anyone wanting to read the whole article. especially notice the first and second paragraphs of PWKs steps to reach his crossover designs. mike
  2. Here is a copy(not the best) of the first page of a article by PWK someone posted before. In the experiment he tells some of the benefits/reasons why he prefered the autoformer method over an L-pad method.Maybe both methods have merit(notice the AK-4 doesn't use the autoformer method but by all I've heard sounds very good) which when the total system design is taken into account one might be prefered over the other Eric: take notice of the network in fig. 2 notice the L-2 in the squawker circuit. Its listed as a .5mh so it looks like early on he designed a network with a bandpass section for the squawker. I can see two ways of thinking about being able to adjust the balance of a speaker systems. 1: (the ideal and prefered situation to me)It would be hard for us to balance a speaker better than a manufacture like klipsch who has the equipment,facilities and experience that the average person doesn't. So if we take this well balanced system and put it in a room and it doesn't sound good we are left with treating the room and setup to bring out the full potential of the system. 2: Most real world situations are that we are limited in being able to balance the room to the speakers needs and one reasonable compromise might be is to within reason be able to alter the balance of the speaker to make the best of the compromises we have to live with. mike
  3. Here is the Dope From Hope paper for those that might not have seen it. At least in one instance PWK found a benefit for a rising impedance at least around this time in audio design. mike
  4. Hey Eric First maybe Al will step in and give us a better understanding of exactly how the autoformer functions and its main benefits in this situation. ------------------------ No1: So, then I thought that the autoformer may also be providing the required inductance needed for this type of first order network -- which is why I was asking for the value of inductance between input tap 5 and output tap 4. -------- From my understanding(from reading the design papers of the ALK network)is the Klipsch A & AA networks don't actually roll the upper end of the squawker off they just let it naturally roll off.Where as the ALK and the type A network shown in another post I believe by John Albright is a true bandpass design for the squawker section that also controls the impedence caused by the autoformer as implemented in the klipsch networks designs by the use of the 10 ohm swamping resistor. As you probably know since the 10 ohm resistor is in parallel with the autoformer/driver part of the network it limits the resistance of this part of the squawker circuit to less than the 10 ohm value of the resistor where as the autoformer/driver impedence will increase with frequency without the swamping resistor causing the the driving amplifier to see a more complex impedence load versus say the ALK design. I remember seeing a paper by PWK about the varying impedance as not necessarly being a bad thing.(maybe I can find it and post it) Naturally the varying impedence will cause some amplifier interaction with the speaker/network causing some frequency response changes which a person might or might not like. The reason the klipsch network uses the 13mfd value is because that value is necessary because of the varying impedance of there network but if you compensate the network for the varying impedance(10 ohm swamping resistor) the capacitor value must change for the proper crossover between woofer/squawker. I see no reason why you can't select the coil and capacitor for a bandpass design with a L-pad. So my question to ALK or anyone else that has a good understanding of this is why is the autoformer better than an L-pad? Does it offer better coupling to the amplifier? mike ps: when you lift the ground side of the autoformer then you basically defeat its ability to attenuate the signal to the squawker.It my as well not be there at that point.
  5. Eric hopefully this is a resized picture of the AA to A with L-Pad picture you posted. mike
  6. Dean said: I still wonder about what John Warren said back when I was playing with this. In effect -- that dropping the output of the squawker 3db by going to the #3 tap doubles the reflected impedance the 13uF cap sees by a factor of two. This supposedly reduces the crossover point from 380Hz to 160Hz. John said if you double the impedance the cap sees, you need to "half" the 13uF cap to keep the crossover point the same. Bob, I know you ran a plot on this that brought the math into question, but I did do more digging and it seemed to me that John was right. I don't think you can just arbitrarily move from tap to tap ------------------------------------- Hey Eric This is similar to what I mentioned in another post to you. It seems to me since the 13mfd cap isn't seeing the autoformer/driver impedance which was higher than the 16 ohm L-pad your using your electrical crossover point has shifted upward. The calculated impedance of the 13mfd cap at 400Hz = 30.612 ohm so if my thinking is correct the autoformer/driver impedance at 400Hz is also approx. 30 ohms. thus the approx. 400Hz crossover point. The calculated impedance of the 13mfd cap at 800Hz = 15.306 ohm so again if I'm thinking correctly with the 16 ohm impedance created by the L-pad your electrical crossover point has shifted to approx. 800Hz. One thought I have is if you used the L-pad after the autoformer your crossover point would stay pretty close to the design point but you would be able to reduce the output of the squawker.If you try this I would really be curious how this sounds to you. This might tell us if the sound improvement you've noticed is caused by the reduction in squawker level or as is probably the case also by the crossover shift and would it maybe sound better or worse if the electrical crossover point is maintained in your setup. I realize that where talking about a 6db per octave crossover in Eric's case so the crossover isn't as quick at dropping the output of the squawker as a higher slope filter would be and thus is more forgiving of this crossover shift but I believe it has to be a part of the differance in the sound as well as the level adjustment of the L-pad. Please don't take anything I'm saying as criticism of what your doing.I'm just really curious what all is really changing with this Mod. and I think it benefits everyone when we can understand why something has the effect it does which when it comes to things in audio "thats a real challenge".I realize you really like the changes you've made and thats what matters and I appreciate how you have been willing to share and discuss your ideas and experiances. mike
  7. Eric said: The way I did this was to take the L-pad body apart, drill a hole in the cent of the metal housing, did a little filing of the shaft, screwed the housing right onto the board in place of the autoformer, installed the actual L-pad back into the housing, and made the connections. -------------------- Hey Eric I'm curious now about this crossover configuration your running now. In your orginal post on the L-pad install you mention a AA-to-A network. So exactly how is your network configured and am I understanding correctly that you have actually replaced the autoformer with the L-pad. For some reason I thought you had installed the L-pad after the autoformer which wouldn't affect the crossover point very much if you used a 16ohm L-pad but would allow you to attenuate the squawker. What value capacitor do you have in the squawker circuit? Looks to me like it would take a change in the capacitor value to maintain close to the same crossover point for the squawker with the autoformer not in the circuit and dependent on the L-pad value. Anyway I'm glad you like this change but I'm trying to understand just what all has changed with this modification which if I'm understanding this right looks like the squawker's crossover point has changed as well as you being able to adjust the squawker level. mike
  8. Hey Richard audioXpress magazine has a books page if you want to actually get deeper into understanding of vacuum tubes/amplifiers. http://www.audioxpress.com/bksprods/index.htm look under; Vacuum Tube Audio - REFERENCE they have two that I'm familiar with plus many more. The two I'm familiar with and would recommend are: Principle of Electron Tubes by Herbert J. Reich Radiotron Designer's Handbook by F. Langford-Smith (this is on a CD-ROM) Maybe some others around here can tell us about other good sources for tube info. mike
  9. Richard try this site for some of your questions on tubes. http://www.thetubestore.com/index.html generally if your amp has bias controls for each output tube then matching isn't necessary but it can't hurt anything.If you only have 1 bias control for each channels set of tubes then you would want to replace the tubes with a matched set. If I had used tubes and one went bad I would probably prefer to replace them as a set with tubes of same type and similar amount of use. mike
  10. Bob My understanding from Stephen Phillips was the T4A is -4db. I learned this when changing my AK2 to an AK3 network in my Khorns. mike
  11. Shawn said: Actually the opposite occurs when you steer a center channel out. You reduce the comb filtering (frequency response interaction) between the L/Rs as they no longer reproduce as much of the same central material and it instead goes to a single speaker. Also because the distance between the speakers gets closer (between L/C and C/R) where they do comb gets pushed up to a higher frequency and becomes less audible. Hi Shawn! Good Point! Of course I was thinking of the center channel with the simple box and even though test might show lots of good/bad interaction our ear/brain is helped more with it than without it. I haven't tried a good processor like the Lexicon and am very interested in Erik's and your observations with it. I enjoy thinking about things like this then trying experiments and then trying to put those observations together to explain why I did or didn't hear what I expected. I often find myself with more questions than when I started. This Hobby is going to keep my mind busy well into old age!! mike
  12. Erik said: It's probably true, too, that careful measurement would reveal some oddities or other characteristics that might not 'look' so great on paper. However: I have no means to test our room response or sound quality other than my ears, which are of course ultimately what will decide on what sounds good or not so good. In this case, the 'good' brought about by the inclusion of a center channel is to such a degree that I have no intention of ever going back to two channels alone -- regardless of what theory or testing might disclose. What I have discovered is a sound so complete, lifel-like, palpable, etc. that it's almost uncanny! Last week I did an experiment where I turned the center channel off just after my wife left the listening room for a glass of water. When she came back, she looked at me, looked around the room, and said, "Did you do something?" "This sounds bad!" The sound she was referring to was the Klipschorns running by themselves in stereo-only mode. --------------------------- Yes Erik! Good test using the unsuspecting wife!! I do similar things with my girlfriend. I like trying something and then without telling her what I've done or what changes I've noticed in the sound I'll get her observation. Since she doesn't get into this critical mode of listening(which is something that at some point in the experiment I try to turn off and start listening more relaxed(natural)mode like at a real event) its a real help hearing her observations against my own. I believe just like you do that the ear will be the final judge! Even though their might be things that don't look good in a measurement the center channel is providing needed information that without it the sound isn't perceived as natural as when the center is providing this information. I(like you) am always trying things for the personal experience/knowledge that can be gained. Like I said I'll be very interested in your observations with the Lexicon unit. mike
  13. Hi NatGun I have a PWR transformer from a DH200 which I'm pretty sure is the same one the DH220 uses. The Transf. should be in good shape I had it left over after modifying a DH200 to a dual momo pwr supply. # on TRANSF. 464002 and 8318150 I believe the 464002 is the number to go by. The DH220 was basically a refinement of the DH200 circuitry and the amps where basically the same. You can have it for the cost of shipping if you want it just PM me with some contact info. mike
  14. Hi Erik FWIW: One problem I've ran into with wirewound L-pads is over time the wiper contact can vary due to oxidation between the wiper contact and wire which just working the control from end to end will temporarly clear up.Yours look like really good quality and the ones I used where fairly good quality also but once they are set and not used over time the connection tends to oxidize over time since the cleanig action of using the control doesn't happen once a setting has been chosen.Maybe you will have better luck with them than I've had. I like to replace the L-pad with resistors. Once I've settled on the setting I'm going to leave it at. I just take it loose and measure it for the resistor values I'll need to replicate it with. I'm using the ALK crossover with the variable autoformer.Its really an interesting learning experience how just a small variance in the squawker setting will show up different things in the recordings by not just the tonal balance shifts but there is some masking effects that show up or nearly disappear depending on the settings.I've also noticed the same effects by how I use room treatments. The center channel speaker you been experimenting with also is an eye opener about how we hear. If you think about it, by adding the center speaker you are changing things more than a person might would think.You will be changing the first arrival times due to the different locations/designs of the speakers(The lexicon if it has center channel delay will change this to some extent and I will be really interested to see how this changes your perception of the sound). You will have constructive and destructive interaction between the speakers.The speaker room interaction changes also.What I've noticed so far using a center speaker is something more natural sounding especially on vocals happens even when the spread isn't very wide (the wider the spread the more obvious the benefits of the center speaker are). Thanks for posting all your experiments! mike
  15. cjgeraci I agree with you that the 7C and 8B are great sounding I repaired a 7C preamp for a friend and the build quality was the best I have seen from the 1960s. After repairing it I tried it with my Khorns and the combination was just a wonderful match and I also found the Tone controls really helpfull with some Music. I really hated to let it go but I couldn't afford it at the time he was able to sell it to a guy in Japan for $2200. My friend also has the 8B and its the best sounding EL34 amp I've heard. Very natural sound to me. mike
  16. When I've heard Khorns at their best they had incredable depth and layering from front to back with instruments and singers having a very lifelike scale(you could clearly hear the back wall of the recording enviroment).The room was approx. 16x25 and I've heard them setup on a short wall as well as the long wall(my preferance) at different times, but both times there was an incredable soundstage and clarity. The room I've described above was a Demo room for the Klipsch dealership many years ago and another thing that would happen was sometimes you could walk in there and depending on how things where aranged in the room they could sound very disapponinting which showed that the Khorn (like any speaker) needs the cooperation of the room to deliver all its capable of BUT give it a good enviroment and IMO its capable of the best reproduction of a recording I've ever heard. I've had spreads of 11.5', 13.5', 17'and 20.5'in various rooms and my personal experience so far is that the Khorn likes 16' and wider spreads to really open up and deliver the kind of imaging I've experienced from them. If you want to know what frustration is go from 20.5' to 11.5'!!! mike
  17. Enjoy Tom Good example of why this is a great forum with really great people!! Very Generous give away Gary its nice knowing there are people like you on the forum. mike
  18. Coytee said: As a partial clarifier, I do not know ANYONE that has tubes and I know even fewer that have Klipsch, let alone, K-horns so leaning on a friend unfortunately, isn't an option. -------------------------- Hey Coytee I live in Maryville,Tn Left you a PM with a Phone No. if you want to contact me. mike
  19. For anyone interested in trying this. I've been using the circuit/setup like Dean posted for several years with my Khorns/Belle. One really good feature I believe is that any characteristic of the main amp is taken on by the center channel amp which will give you the best match between channels if the amps being used are different. I've used a 2A3se amp with a 6BQ5 push/pull mono amp for center channel and the sound is so good I have not felt the need to build a 2A3se center channel amp. Another thing I've done lately is feed the signal from the box into a creek OBH-10 passive volume control into the center channel amp. This way I can control the volume of the center channel or mute it for comparison of with/without the center channels contribution to the sound. This is really important to me because different songs and CD's sometimes benefit from a different center volume setting and being able to do this from my listening position is ideal. mike
  20. ---------------- On 11/24/2004 4:18:23 PM Painful Reality wrote: Shouldn't the squawker be wired in reverse polarity compared to the woofer and the tweeter despite the factory schematic showing it wired in phase? ---------------- Actual driver locations in relation to each other and the listener can change which polarity to use on the individual drivers for the best acoustical blending. So in other words the networks ,driver physical locations and listener locations have to be taken into account when selecting the proper polarity for the individual drivers. mike
  21. I heard the orginal forte in the same room with Khorns using the same equipment and I was very impressed with how close the sound was to the Khorns. I've owned chorus spk. and my preferance would be for the more extended bass and tonal balance of the forte. Both systems will play as loud as I would listen to music. The best thing would be for you to seek out the other models(maybe some forum members in your area could help in this or if any of these come up for sell in your area) and listen to the compromises klipsch made for each design and pick the model that best fits your taste and needs. Enjoy the forte speakers they will definitly give you alot of the Khorn sound for very little money. mike
  22. coytee said: Mike: The watermark seemed to just evaporate out and now I dont see it. If and when these DO go into the basement, it will be on a tile floor over concrete. The walls are block walls w/poured concrete inside. (then Ill drywall the actual interior surface). The downstairs room is something like 16 wide by roughly 24 I think. Been while since Ive measured. Nine foot ceilings. --------------- Man that downstairs room sounds like it has some great potential for an audio room! I would love to have a space like that to work with.Ending up in the basement might be a great thing in the end! mike
  23. great looking Khorns coytee did the water spot you posted about come out OK? what did you end up doing for that? If your basement space is a good size and dry it would be nice to have a space to dedicate to the klipschorns so you can set things up for best acoustic purposes with less compromises maybe.I would love to have mine setup on a "solid" concrete floor. mike
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