pkeller

Hi: It's been a while since my last post and this may seem weird, but..... try your Heresy's on their side with tweeters toward the middle (each other). The improvement in soundstage and imaging is substantial. Get out your most familliar, naturally miced, recording and angle the horizontal Heresy's directly facing your listening position. If your audio system and your listening habits have been crafted to maximize imaging, you will not change them back to the verticle position. It will cost you nothing to try and is totally reversible. Let us know what you think after you've given it a try. Paul Keller

Hey Gang: Could somebody please send Al K. a pair of beat, up but functional, first generation Heresy's (E-network)in trade for some of his crossover work. Looks like he needs a pair of Heresy test platforms. There has to be some K-horn, Belle, LaScala, Cornwall owners out there with a set of beat up Heresy's their not using. With the potential increase in sales, Al could probably use a stunningly beautiful assistant as well. Paul K.

Sorry about the multiple posts. I keep getting messages that my posts are not being accepted. Obviously not true. Paul

I had thought the same thing. The problem is that the T/S perameters of the woofer are designed for a sealed enclosure. The balance of bass v/s mid would not have the same ratio of response. At higher volume levels, the sealed design of the Heresy depends on internal compression and rarification of internal atmosphere. It would be risky and non-linear to drive the woofer "unloaded" at such excursion levels. A tuned port might be used to augment the low response if the Thiel/Small measurments were known. This would limit low frequency excursion if the desired tuned frequency is close to the acceptable perameters of the woofer. Still, there would be all kinds of non-linearities in response. Better towork up a new crossover design using Klipsch tweeter and midrange and a more compliant "but efficent" woofer. Good luck: Paul

I had thought the same thing. The problem is that the T/S perameters of the woofer are designed for a sealed enclosure. The balance of bass v/s mid would not have the same ratio of response. At higher volume levels, the sealed design of the Heresy depends on internal compression and rarification of internal atmosphere. It would be risky and non-linear to drive the woofer "unloaded" at such excursion levels. A tuned port might be used to augment the low response if the Thiel/Small measurments were known. This would limit low frequency excursion if the desired tuned frequency is close to the acceptable perameters of the woofer. Still, there would be all kinds of non-linearities in response. Better towork up a new crossover design using Klipsch tweeter and midrange and a more compliant "but efficent" woofer. Good luck: Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Probably needed with the higher level of output in the 101db Cornwall's Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Probably needed with the higher level of output in the 101db Cornwall's Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Actually, a pair of beat up non working but complete Heresy's gets you the tweeters and mid horns for the Cornwall and Belle. Finding a compatible woofer will be the tricky part. If you knew the Q measurments and SPL @1x/1m of the Klipsch woofer version, you could find something close using the LDSG. http://www.snippets.org/ldsg/ You may need to add a new diaphram or two and of course, purchase parts for the crossovers. The rest is securing plans for your desired model. I personnaly would like the early Cornwall version with verticle horns. Does anybody know of a source of plans for these? pkeller@ix.netcom.com

Klipschguy: I'm really at a loss as to why your tweeters are excessively bright. Most of the modifications you site are for the "mid" horn in the Heresy's. My K77's being alnico, and yours ceramic may explain part of the difference, but not to the extent you describe. I was thinking that possibly you have mid drivers that have an extreemly agressive 9khz return resonance. Since the tweeter takes over at 6khz, this would add substantially to the perceived tweeter level. A large 9k spike in response from a non-linear region of the mid driver could introduce a secondary harmonic that feels like your sticking a pencil in your ear. Not every Atlas mid driver resonates at 9khz, so it stands to reason that some may resonate a "great deal" at 9khz. When you reduced the tweeter level, it could have brought the overall 9khz region more into balance. I am not at all confident that this is what happend. It's only a theory. In any case, you may want to try the P-Trap before any further crossover mod. I know that my Heresy's became a lot more civilized when I added the P-Trap. It could be that the return resonance at 9khz is at a fixed volume and becomes less of a factor in the more efficient Klipsch designs using the Atlas mid driver. Dang I hate to be baffled like this. Keep us posted. pkeller

I've been thinking that the bright voicing of the Heresy's might be due to amplification. Heresy's were designed when tube amplifiers were the standard. Tubes have a softer cleaner high frequency presentation ("generaly speaking", no flames needed) and a more pronounced mid response. I am using tube amplification for evaluation and testing. This might explain our difference in tap location needed. Especially if you using solid state equipment more than about 15 years old. SS equipment, including pre-amps were pretty bright back then. What are your driving components? Paul Keller

I doubt the Aerovox caps have changed much over their 26 years of life. I don't know of any source for them presently. Even if you could find NOS Aerovox caps, their age alone will make them close to what you already have. The miniscule current used by the mid and tweeter in 101db speakers is really not a degrading factor. The big reason to use premium modern film caps is to attain superior detail and extension in the high tones. There is no question that the Northcreek Zen 2.0uf caps have greater transparency than the stock caps. This comes at the loss of some smoothness that the mid squawker requires. For this reason, I bypassed both the 2.0's with .1uf Northcreek Crescendo caps. This smoothed things out a great deal without loss of the transparency or extension. The P-Trap also requires some modification. I used Zen 3.0uf but found that it too needed bypassing. I only had a Harmony (again Northcreek) .22uf at hand, so I used it with good results. I'm going to try Crescendo caps for the P-Trap in both base and bypass mode. I hope this adds to the transparency even more, but at this point I'm fishing for even better results. I should say that Northcreek caps behave much differently than most all other caps on the market. Normal metal film caps will become bright and hissy when used in bypass mode. This is not at all what Klipsch networks need. Not so with the three lines of Northcreek caps. There is also concern regarding the addition of capacitance value when bypassing. Making a 2.0 into a 2.1uf is only a 5% change for the mid horn and 10% for the tweeter and not noticable given the gradual 3db design slope of the stock "E" network. As for moving the mid and high frequency taps on the autoformer, I have avoided trying this as it changes the impedance of the system a slight bit, but probably not a significant amount. This network sounds well balanced with the stock locations used. If anything, I would lower the squawker 3db, but that might be a bit too much, so for now it will stay. You do have my curiosity tweeked, though. My Heresy's still sound like Klipsch designed, but with a higher livel of surrounding ambiance and detail. All of the above has been done without tearing into the stock Klipsch networks. I can reinstall the stock boards in a few minutes if I desire. This is only insurance should I decide to sell the Heresy's some day. But I don't see that happening any time soon. Paul Keller

I really depends on the construction of the cap. Electrolytics, for instance, change the most with time due to degredation of the one molecule thick conductive film electroplated to the dielectric. Heresy 1's with the "E" network use sealed paper in oil caps that are very stable and change "very" slowly. They have, however, been surpassed by the sonic character of some more modern caps. Recently, I have been evaluating an "E" crossover network for the Heresy 1's that uses close to stock layout and component values, but has upgraded parts. While not yet perfect, the result has much more high frequency extension, imaging, soundstage, and transparency. This netework depends heavily on the use of bypass caps across the base film caps. It also depends on the "P-Trap" notch filter needed for the K55-V Atlas mid driver used in series 1 Heresy's. I'm still not convinced my mid horn cap combination is optimal, but it's very very close now. Different brands and bypass values have yet to be tried though. It is significantly better than the stock network at this point. I have detailed much of the parts used in the basic rebuild in other posts on this forum. What remains is fine tuning that has yet to be perfected, but presently, it's close. The bass is forever limited by the Heresy woofer design required to blend with the mid horn, sealed cabinet, and high efficiency at upper bass frequencies. I'll eventually use hidden powered subs to fill in frequencies below The Heresy's reach. Paul Keller

I was not sure if the Heresy II's would have the same effect when turned sideways as the Heresy 1's. The flush mounting of the horns and different horn material, as well as crossover changes left some doubt. From your description, it sounds like the effect is pretty much the same for both series. Thanks for posting your findings. I have yet to turn my Heresy's verticle after putting them on their sides five months ago. It's not a tough choice once you try them sideways. I've found that "tweeters toward the center" works best for my environment. Other rooms may have different requirments. pkeller

For those interested, here is a photo of the Heresy 1 crossover rebuild. It is stock in component value and topography, but uses a 14ga Perfect Lay inductor and Zen 2.0 caps. Not shown is the "P-trap" or the Crescendo .1uf bypass caps across the Zen's, that I currently have installed in my Heresy 1's. Paul Keller

Actually, yes it has smoothed out quite a bit. I do have some Northcreek Crescendo .1uf 800v film & foil bypass caps on order to try in parellel with the 2.0 Zen's. I'll post the results when I get them installed. At this point, I don't really think they will be needed, but I'll try them anyway. The best description I can make between the stock crossover -vs- the new version is like the difference between pentode and triode tube amps. The stock network is like the pentode mode. More forward and centralized in presentation. The new version is like triode mode. More detailed and spacious, but less forward. Imaging is far-far better. It really takes advantage of naturally miced recordings. Currently I have been listening using a very fine sounding rebuilt Dynaco ST-70 (I have three). Other amps I've used include Heathkit EA-2's, UA-2's, and Allen Organ #75's. All of them at partial or full restoration. They all do well with the new crossovers. Hope this gives some perspective. Paul

Here is the Heresy schematic that I tried to attach to the last post. Al K. posted it some time ago but it is no longer in the archives. As for the numbers on the autoformer in the photo from the previous post, they are: 3619 0027 or it could be "OC27", I can't quite tell. It was ordered from UTC. Paul

I've tried to attach a photo of one of my rebuilt X-overs and a copy of Al K's Heresy "E" schematic. Neither attachment contains the "P-Trap". I hope this works. By the way, below is a list of parts used for the crossover and P-trap. X-over: 14ga 2.5mH Perfect Lay inductor(Madisound) (2)2uf Northcreek Zen capacitors T2A autoformer (Universal Transformer Co.) P-Trap .1 Heptalitz inductor (Solen) 3.0mh Northcreek Zen capacitor

Here is a photo without the P-trap installed. I hope this attachment works. If it fails, send me an e-mail address and I'll bypass the BB. Paul

The Solen Heptalitz inductors for the "P trap" was purchased from Solen. It was a Canadian address that I cannot find right now. It was in the archives in a post by Al Klappenberger. All caps were Zen and purchased from Northcreek. The autoformer was from Universal Transformer Company (UTC). The large network inductor was Madisound Perfect Lay air core 14ga. As I listen to the Heresy's more closely, I'm finding that there is a mild harshness in the upper mid that does not blend well with all types of music. I am being very picky. There is no question that spaciousness and detail is much better with the new system. You can really "feel" the ridges of Martin Taylor's finger prints as he plucks the strings of his guitar. To go back to the stock network would sound a tad confined and thick by contrast. In reading Northcreek's information about bypass capping, It looks like it may work well to tame the mild harshness while retaining the clarity. The single bypass cap would be added to the 2uf cap beween the + terminal and the autoformer. I mis-wrote in the above post regarding the Harmony bypass caps. I should have said "Crescendo" .1uf 800v cap. I have yet to try it though. All values were stock. Hope this answers what you need to know. Paul

I have several hours on the new crossovers now. Mids have gotten even more in balance with the tweeter and woofer. I was reminded by another BB participant that if the squawker neg. was moved to another tap on the autoformer, it would require a cap value compensation due to the inductance change. There is no need anyway since squawker strength is no longer an issue. The Heresy's have gotten much more depth and clarity to their image presentation. High frequencys are more extended and delicate when called upon for detail. I think the stock oil caps were holding them back from the upper reaches a bit. The bass has an effortlessness that it didn't before. The transient bass response, like when Ray Brown plucks a string, has more vibrancy and immediacy than before. The strength of the bass is about the same, just quicker. This crossover system would probably mate well with SET amplifiers, as it is "very" revealing. 30 year old solid state amplifiers, like a Dynaco ST-120, would be awfull. You would hear all of that bench grinder like character (yes, I have one)(in the closet). The next mod I'll try will probably be a bypass of the Zen caps with Northcreek Harmony .1uf caps. This only represents an insignificant 5% change in cap value and is supposed to allow even more detail. I'm going to wait a while so I can get used to the existing network though. Paul Keller

Reposted from "P-Trap" topic. OK, I finally got around to swapping the stock Heresy type "E" crossovers with the new ones mentioned a couple posts above. My Heresy's are 1978 (alnico) vintage and have had the "P trap" installed for the past several months. I have been changing other things in my audio system recently (amplifier mods), so I had to get familliar with the sound before I could make any meaningfull comparisson of the two crossovers. Now the results: First impression (installed 5 minutes ago) is that the tweeter has more detail and delecacy. There is a bit more transparency and detail across the entire audio range. Bass is more controlled and a tad stronger. Imaging and dynamics are enhanced. Now the down side. The midrange, while cleaner, is slightly too strong. Remember that this system does include the P-trap. This may be corrected by a simple relocation of the squawker "-" wire to the #1 tap on the autoformer, rather than the stock #2 location. This would lower the mid horn -3db and probably be about right. To be fair,the new caps have not had a chance to settle in and the excess mid might take care of itself in time. It's not too far off as it is, but could be better. Over all, the new crossover has much more potential than the stock unit. The much larger inductor and Zen polypropylene film caps are clearly superior to the 23 year old components they replace. As for the UTC autoformer, It's about the same size as the stock unit. Al Klappenberger made some measurments of it a while back and found it better, so I used it. I have a photo of the new crossovers, but I'm having trouble attaching it to this board. Can anyone tell me how? As I type this, the sound comming from the Heresy's seems to be getting better. Even more detail. Either the mids are settling down a bit or the highs are getting stronger and more in balance with the mids and lows. Just for refrence, Im using modified Heathkit EA-2(12 watt 6BQ5/EL-84) amplifiers. Efficiency is about the same as before. I won't be changing back to the old networks. I have about an hour of listening time now (I type slowly) and the mids are getting to be about right. Detail and transparency is increasing as time passes. I'm Jazzed. Hope all this helps. Paul Keller