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tigerwoodKhorns

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Everything posted by tigerwoodKhorns

  1. The electrolytic is parallel to the woofer so not in the signal path. FWIW, Roy had said to use an electrolytic and not go to a film or poly cap as it would not make a difference ( I am assuming the last part). I just went with electrolytic from Parts Express.
  2. I glued two 1/2" strips of wood to the bottom of the cab and put screws in. I also made a jumper from the plate to the X-over. I have done this in other speakers. This took a huge amount of time.
  3. And be prepared to spend a lot of time to get things done nicely. The first time you do a job, it takes a while to learn what needs to be done (layout, parts, etc.) so be ready to spend some time to get a professional looking result. Here was my solution to big caps in the Chorus IIs: Just before I installed the final caps. Or ordered for several speakers and was short a few caps so I was waiting to check capacitance and match pairs.
  4. Even more awesome! Keep it going.
  5. Without reading the last three pages of this thread, if the exact value cannot be obtained, he can just source the next higher value and unwind it a little, can't he? It has been a while, but here is a calculator that I used in the past: https://www.diyaudioandvideo.com/Calculator/AirCoreInductorDesigner/
  6. That and Digikey. If you do not know exactly what you are doing, good luck.
  7. I had a pair of perfect Belles and matching Heresies that looked just like these years ago. Sold them all to a forum member. Just ran out of room to keep them. GLWS.
  8. I'd try some black model paint. Remember Testors paint from when you were a kid? I just bought some at Hobby Lobby to repair a scratch on a piece of gear. $1.99 each. That and a very small artists brush. Maybe start with a coat of copper paint, then go over the details with the black. The 'PWK' is going to be tough.
  9. If hew wants to make $5 an hour for his efforts then yes it is worth it. That was my point.
  10. My point was to either do them right or just sell as is to a person with the skills and desire to restore them. It is not worth the effort to get a few hundred more dollars if you do them correctly. I'd either want a perfect speaker or pair that some one has not touched. Poly is a preference, but my Chorus IIs are as smooth as glass. Much nicer than the original oiled finish and not they do not need maintenance.
  11. I heat up the plastic and remove the metal 'tube' portion of the crimp connector, crimp the connection, then solder it and cover in heat shrink. It takes me a while to complete my projects...
  12. IO just recapped some Fortes and Chorus with Jantzen Standard Z Caps, they sound great. I want to see the cost of meters come down more so an occasional user can test ESR. That would be very helpful. Funny you mention 50 years. I was restoring some L100 Centuries and Dean had mentioned that the caps in those are very high quality sealed caps that will last 50 years. I thought ah heck, I don't need to replace these, until I realized the speakers are 50 years old.
  13. The 'Huge difference' kind of got me too, seems to hurt the credibility of the claim. So what caps would you use in the 250 TIs? In the last ten years I have stuck to Clarity Caps and Jantzen Standard Caps.
  14. I found this on Audioheritage, the caps used in the S5500, it looks like they used a mix of film and electrolytics: 'I really don't think JBL selected the capacitors based on anything other than cost saving. They are budget bennic style film caps and the larger values electrolytics are ALCAPS found in every budget speaker of the time. Nothing high end here. Just working to a budget keeping the bean counters happy. Giskard recreated numerous JBL networks and never mentioned the importance of keeping the original capacitors, from reading his posts he used anything from Solens to Jantzens. As long as you match the values closely I think using a higher quality capacitors isn't going to harm a thing.' I also found GT's posts in my server: Here is his post from 2008 : 12-02-2008, 05:25 PM #3 gtimbers Member Join Date Sep 2005 Location Los Angeles Posts 30 I was asked to make a brief response to this last post, so here it is. The capacitor biasing is something that has existed for many years. Tube equipment does it automatically since there is usually a large DC offset between stages. Some early transistor amps/preamps had two polarized caps in series with the center point going to ground through a large resistor. I personally became aware of this technique for speaker systems through communications with Ed Meitner, currently of EMM Labs. He is a wealth of information regarding these "tricks" to help linearize or improve the sound of passive components. It turns out that the bias trick actually increases measured IM distortion and the higher the bias voltage, the greater the increase. It is not by a great amount, but it is measureable. The sound imporvement (or change) is very rarely perceived as worse and is never linked with a increase in IM distortion. The sonic effect is one of smoothness, increased spaciallity, detail and stuff like that. IM has a muddling or confusing effect so I doubt that this particular steady state measurement is explaining the sound difference either way. Simply put, we are striving to create a class A situation but as was just pointed out, depending on the bias voltage with respect to the voltage across the capacitor, we may only have an "A" condition up to a particular drive level. So if it makes you happier, consider the change to be class AB, but heavily biased to A. You must also keep in mind that the voltage across the input terminals of the crossover network does not tell you what voltage or current is applied to any individual component. Some parts block signal and others shunt signal so the loading on a particular part is not obvious. For the most part, the caps are well taken care of with 9 volts, even at healthy drive levels. The obvious choice for 9 volts is the small cheap battery and holders that are available. No current is involved so a smoke detector battery and holder is a natural choice. We did do one system with 18 v (M9500). Certain of the Japanese reviewers thought it was an improvement. I can't personally tell any difference. I am also told on a regualr basis (again by our Asian customers) that the battery must be changed at least every 90 days and that the sound degrades after that. Once again, I have not been able to "hear" any difference after 90 days and the battery is certainly still good for many years from a voltage standpoint. What playing around I have done with initial application of a battery to a biased circuit (that has not been previously powered up) is that it takes about 3-5 seconds for the soundstage to change. I have tried to measure the voltage level in that time period and it seems that several volts is all that is necessary to accomplish 90% or more of the improvement. Once a circuit has been energized, it is nearly impossible to return it to zero. You have to individually short out each cap and leave them shorted for a while or else they will creep back up somewhat. If you replace the battery with a short and play the system for a while, the caps will start to bias themselves, although not to anywhere near the same degree. You can take this opinion for what it has cost you. I have been very pleased with biasing for many years. I use it in all applications that involve a capacitor and I have rarely been disappointed. Results may vary so if it doesn't do it for you that is okay too. It cost a bloody fortune to implement as it requires 4 times the capacitance and double the capacitor parts count. The network size gets huge as well. In spite of this, I have never heard a capacitor type that didn't improve (or change) including the nearly perfect teflon variety. *** ** Here is his post from 2006 where he had done the mod to his own 250s and really liked it. He is responding regarding a studio 4 way but discusses the 250TI 05-02-2006, 04:56 PM #27 gtimbers Member Join Date Sep 2005 Location Los Angeles Posts 30 You Guys are Amazing I can't belive all the interest in this 30 year old system. It was never very successful during its life time primarily due to its size. Most people would get something smaller. It also had a reputation for less than detailed bass, which I have always thought was due to the enclosure not being quite large enough. I haven't thought about these things in years but since I have received a few requests for comments - here goes. The system was and probably still is a stellar performer if you like the inherent sound of the traditional big JBL 4-ways. There is good news and bad news in the basic design. Good in that they are dynamic as hell and never get confused with intermodulation products of any type. They don't take much power to run and can swallow up a really big amp should you wish to do so. The weak areas of that type of design are several. First, there is a large time off-set between the 10" driver and the HL92 horn. This shows up in both the on-axis response, the directivity pattern and the homogeneity of the driver blending. The second problem is the use of a passive crossover between the top of the woofer and the bottom of the 10". Passive crossovers set to frequencies below about 500 Hz react badly with the motional impedance of the woofer/box combination and give substantial gain around 100 Hz. Gain out of a passive system is generally a bad thing. In the case of the High Pass, we have to work the passive network through a really large motional impedance peak resulting from the 10" fundamental resonance in the sub enclosure. This means that the actual voltage drive that occurs at the terminals of the 10" is less than ideal. There was the added complexity that the Marketing folks of that time required switchable bi-amp capabilities in which the incorrect setting of the switch was not allowed to hurt anything. These little things all add up to additional insertion loss for the woofer and loss of damping control. Now all of this sounds pertty bleak, but as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway. My sonic memory of the big 4 ways, the last of which was the 4344MkII, is that they are effortless, dynamic, pretty low in coloration and really "alive". They are a little vague by today's standards in terms of precise imaging and although they are very low in intermodulation effects, they are not as detailed as really good lesser way designs. There is no simple answer to any of this and no one design statement that is best. Everything is a series of compromises, and the 4345 has a very good set of complimentary compromises. I noticed a comment earlier in this string regarding the 2122H. It is a really good voice transducer. It always has been and always will be. Things just sound really natural through it. Another one that might be slightly better is the 2123. It is a little less smooth but perhaps a little more realistic on voice. Either are really good for that critical range from a few hundred Hz to about 1500 Hz. I imagine you guys have talked about and tried lots of things to get the most out of the system. I will mention a few things that I would do if I had a pair at home for my primary system. Get rid of the bi-amp switch. Hardwire it in which ever mode you want it. The switch is not that great. If you can work out bi-amping do so. The difference in the 2245H and 2122H will be amazing. The crossover will have to be non standard. Neither driver is flat around crossover so the voltage drives will need to be adjusted to get proper acoustic bandpasses. The network components should be updated and this isn't easy. All the capacitors should be polypropylene and you would want to use air core inductors where ever possible. I believe the 4345 used some tapped iron cores. Those are hard to replace with aircores because the surrounding network topology would have to change and all of the values have to be re-engineered. I would suggest leaving them alone unless you are really good at this stuff. If you can swing it, go to a biased network. The difference is unbelievable. The ring radiator hates passive networks. A major improvement in the upper range would be to drive the 2405 from its own little amp. You only need 3 or 4 v rms. The 2405 does 110 dB for 2.83v. It is padded way down in the system. There is little real power at those frequencies anyway. You only need to know the voltage output of the amp, power is irrelevant. The 2405 is about 12 ohms and won't draw much current. I would use some little chip amp with a 2ond or 3rd order low level highpass in front of it. Take off the passive network to the ring and just feed it straight. Make sure the amp doesn't make a DC thump on turn on or turn off. That will fatigue the diaphragm. The amp will also have to have really low noise characteristics as any hiss will be really loud directly into the ring. I used to use an old Marantz 1030 integrated amp to run my rings. I could separate out the power amp section and the tweeters always sounded really good. The L-pads aren't so hot either, particularly after all of these years. Once you have your preferred balance, it is fairly easy to measure each leg of the L-pad and replace it with fixed resistors. I notice from many of the pictures that the system is elevated on blocks. It is very good to get the 2245 up off of the floor to minimize midbass fatness. For resale reasons, you should be very careful about doing as much of this as possible reversibly. Before closing I should comment briefly about the 250 - 4345 comparison. Simply put, I prefer a 250. I like the bass quality of the LE14 woofer. Alway have and always will. The 2245 when used as a dedicated sub is one of the best sounding woofers ever. It has an amazing blend of speed, pitch and punch. So does the 14" but the 18" is better. Unfortunately the 18" dislike for passive networks hurts it more than the 14" is hurt by a passive network. I think the mid and high range on the 250 is smoother and much more open however the 4345 wins by a bunch in terms of effortless dynamic sound. I have made all of the above changes to 250 systems (except for separate amp on UHF) and the improvement is huge. I have not done so on the 4345 but I suspect that that system will benefit from theses changes more than a 250 would. If both systems were tweaked out to about the same level, I suspect it would be very hard to come up with a clear overall winner, but I think I might lean towards the 4345 as having the greater potential. Thank you all for the interest in my work. I must admit I have been blessed with a really nice profession that has treated me well for a very long time. Remember that sound and music enjoyment are very personal things and that what makes you happy may or may not please others. Screw them. If you are happy and no one is geting hurt then go for it. No loudspeaker system even approaches real life so there is plenty of room for interpretation.
  15. I can only say that Greg Timbers was very skeptical at first and then later subscribed to doing this. Likely after testing and listening. I need typo dig up his posts.
  16. I struggle with this. If charge coupling improves a cap's performance, say of a Solen or Dayton, because there is so much more capacitance used, are you better off with just using higher quality caps? The interesting thing is that Timbers seemed to think that it was an improvement after he was at JBL just in comments in a forum.
  17. Greg Timbers was skeptical at first and now advocates for Charged coupled. A member at the Lansing Heritage forum said his Everest were sounding 'grainy' and after a while he realized he needed to check the battery and that cleared them up. Greg said to just make sure to use film caps and Solens are what everyone was using about ten years ago. I have a pair of 250 TIs that I am considering going charged coupled per Greg Timbers comments, but with that network the cost of the caps really add up. He is the designer so I will most likely just trust him and go that route.
  18. Captain already said it, look at the graphs above. There is a seller of Russian PIOs near you. That would be my first choice in EU.
  19. Very good point. Same problem with Pink Floyd. It is annoying. I am listening to 40 licks by the Rolling Stones and it is a really good compilation without the issue. Another really good compilation is Eric Clapton Complete. Great set and really good price. I have it on Vinyl and am temped to get the CDs as they are easier to play in my family room. https://www.amazon.com/Complete-Clapton-Eric/dp/B000UAE8CQ
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