ka7niq Posted December 20, 2009 Share Posted December 20, 2009 I HATE this freaking forum, I HAD a post that took me 1/2 an hour to type, and LOST the post, trying to tag the gad dang thing! I bought these Cornwall 2's locally here in Tampa from a man who bought them from Betty, on this forum. I want to get inside them to check connections, replace caps, etc, etc. Any idea how to get at the crossover, and anyone have a schmatic of this crossover, soo I can order caps from Madisound ? DJK is right, these are good seakers, FAR better IMHO, to the 2 sets of Cornwall 1's I have owned. DJK was right about the original Forte's too, a great speaker, for the money, just too small for my tastes/room. Quote Link to comment Share on other sites More sharing options...
Bill H. Posted December 21, 2009 Share Posted December 21, 2009 Get ahold of member http://www.critesspeakers.com/prices-crossover_repair_kit.html He Has copies of the Scematics.............his repair kit is Only 50.00.............. Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Bob is a great guy. I just need a cornwall II crossover schematic to get the parts values, I just might have the needed caps already ? I wonder what other tweaks Cornwall 2 owners have done ? I think the midrange horn is plastic ? In that case, it shuold not need rope caulk ? Quote Link to comment Share on other sites More sharing options...
Bill H. Posted December 21, 2009 Share Posted December 21, 2009 Rope caulk is a wifes tale..................Not Needed . http://www.alkeng.com/dload_xo.html Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Yeah, especially on plastic horns. More interested in crossover parts upgrades, and to do what I think DJK said to do. I have to check the old thread, but I recall him saying to solder the wires directly to the drivers/crossover that use push on connectors ? Maybe there are some more Cornwall 2 Tweaks/Mods that make good sense ? I have owned 2 pairs of Cornwall 1's. DJK is right about the Cornwall 2, it is a much improved speaker IMHO then the Cornwall 1. I was up till 3 am last night listening to the Cornwall 2's. Can't wait to get inside them, and update the crossovers, if I only had a schematic ..... Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 Cornwall II schematic. Bob Crites Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Cornwall II schematic. Bob Crites Thanks Bob ! The woofer cap, is that 68 mfd, or 6.8 ? Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 It is 68uF. Bob Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 Picture of the early Cornwall II gnarly crossover before they had them built on a circuit board. Burn on the edge by cigarette or soldering iron may have been an added option. Bob Crites Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Picture of the early Cornwall II gnarly crossover before they had them built on a circuit board. Burn on the edge by cigarette or soldering iron may have been an added option. Bob Crites Thanks Bob ! Those look like Mylar Caps ? If they are Mylar, I would not think they would be Bad ? I have never measured a bad Mylar capacitor, unless it was blown up. They seem to age well ? Many Mylar Caps are pretty high in ESR, if I recall ? The reason I am asking this Bob is because the tweeters in my Cornwall 2's seem a little slow, or sluggish sounding. Perhaps the diapragms are aging, and replacing them will be a better course of action then replacing Mylar Caps that are most likely still good. What is your experience with refurbishing Cornwall 2's Bob ? What do you see your Cornwalls II customers doing ? Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 Most of my customers completely replace that crossover. Some rebuild it on the same board using lots better caps than those on the board. And most of those cheap little blue caps test pretty bad by now for ESR at least. Most also opt for the titanium tweeter diaphragms to liven up the tweeters. They are smoother and extend higher. Bob Crites Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Most of my customers completely replace that crossover. Some rebuild it on the same board using lots better caps than those on the board. And most of those cheap little blue caps test pretty bad by now for ESR at least. Most also opt for the titanium tweeter diaphragms to liven up the tweeters. They are smoother and extend higher. Bob Crites Ok, that was allI was waiting to hear Bob ! I see on the Cornwall II Tweeter K 79 Titanium Diapraghms on Ebay from you. But before I buy them, what about the K 52 midrange diapraghms Bob. Do you think they are OK, or are there upgrades there too Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Most of my customers completely replace that crossover. Some rebuild it on the same board using lots better caps than those on the board. And most of those cheap little blue caps test pretty bad by now for ESR at least. Most also opt for the titanium tweeter diaphragms to liven up the tweeters. They are smoother and extend higher. Bob Crites Forgot to ask you WHY you dont use the felt damping pad under the new titanium diapraghms for the Cornwall 2 K 79 driver Bob ? Just wondered ? Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Most of my customers completely replace that crossover. Some rebuild it on the same board using lots better caps than those on the board. And most of those cheap little blue caps test pretty bad by now for ESR at least. Most also opt for the titanium tweeter diaphragms to liven up the tweeters. They are smoother and extend higher. Bob Crites Bob, WHY would one replace the whole crossovers ? I mean inductors dont go bad, right ? Why NOT replace just the Caps, am I missing something ? Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 No upgrade to the midrange yet. I have so far had two different prototype titanium diaphragms made for that midrange and have rejected both of those samples. Bob Crites Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 The pad is just not needed with the titanium. Tests better without it. Bob Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 Most of my customers completely replace that crossover. Some rebuild it on the same board using lots better caps than those on the board. And most of those cheap little blue caps test pretty bad by now for ESR at least. Most also opt for the titanium tweeter diaphragms to liven up the tweeters. They are smoother and extend higher. Bob Crites Bob, WHY would one replace the whole crossovers ? I mean inductors dont go bad, right ? Why NOT replace just the Caps, am I missing something ? No, they don't generally go bad. Some additional gain in performance might be achieved by having all new and higher quality parts all the way through but most of the improvement would be from the better caps. Bob Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 No upgrade to the midrange yet. I have so far had two different prototype titanium diaphragms made for that midrange and have rejected both of those samples. Bob Crites Well, if no upgrade diapraghm are for sale, how do you know if your diapraghms are good, or not. The midrange on my cornwall 2's sounds ok, it is the tweeter "air" or sparkle I find missing. What is life expectancy of the K 52 midrange drivers diapraghm, in normal use ? I guess what I am asking is if the diapraghms are like a transistor, or a Tube ? The transitor either works, or it dont, but the tube can work, but still be weak. Quote Link to comment Share on other sites More sharing options...
BEC Posted December 21, 2009 Share Posted December 21, 2009 No upgrade to the midrange yet. I have so far had two different prototype titanium diaphragms made for that midrange and have rejected both of those samples. Bob Crites Well, if no upgrade diapraghm are for sale, how do you know if your diapraghms are good, or not. The midrange on my cornwall 2's sounds ok, it is the tweeter "air" or sparkle I find missing. What is life expectancy of the K 52 midrange drivers diapraghm, in normal use ? I guess what I am asking is if the diapraghms are like a transistor, or a Tube ? The transitor either works, or it dont, but the tube can work, but still be weak. They are usually good if they are working and you don't hear anything "funny" out of them. To know more than that would take a spectrum analyzer and calibrated mic. Bob Quote Link to comment Share on other sites More sharing options...
ka7niq Posted December 21, 2009 Author Share Posted December 21, 2009 Most of my customers completely replace that crossover. Some rebuild it on the same board using lots better caps than those on the board. And most of those cheap little blue caps test pretty bad by now for ESR at least. Most also opt for the titanium tweeter diaphragms to liven up the tweeters. They are smoother and extend higher. Bob Crites Bob, WHY would one replace the whole crossovers ? I mean inductors dont go bad, right ? Why NOT replace just the Caps, am I missing something ? No, they don't generally go bad. Some additional gain in performance might be achieved by having all new and higher quality parts all the way through but most of the improvement would be from the better caps. Bob OK Bob, I will order the titanium diapraghms for the K 79 tweeters from you. For the sake of this thread, I ordered all the caps to re do my Cornwall II crossovers from ERSE. I met Jim Thiel in Seattle years ago. He used the ERSE coils and Caps. I have had good luck with their coils and capacitors, over the years. Thiel uses Erse Poly Caps in the Thiel 3.7 !!! I have used these ERSE Poly caps on Speaker Factory Corner Horns, and on several pairs of Advents I have re capped, with excellent results. ERSE had every exact value for the Cornwall 2's, all from one company. Even had the 68 mfd bottom crossover cap too! Total price to redo BOTH Cornwall II Crossover Capacitors completely was 48.99 shipped, leaving "room in the budget" for some new titanium diapraghms from you! When you see a pay pal order come through from Chris Tucker Bob, that would be me. If ya can ship them soon, maybe I can get everything singing between xmas and new years ? Thanks for everything Bob, and when and IF you get better diapraghms for the Cornwall 2 midrange driver, put me down for a pair! Dear chris tucker,Thank you for shopping at ERSE Audio.Your order no. 225-58731 has been received.Order Summary: Item Qty Description Options Rate Amount 1.5µF 250Vdc PulseX Cap 4 1.50μF 250v PulseX - Metallized Polypropylene Film Capacitor $1.19 $4.76 3µF 250Vdc PulseX Cap 2 3.00μF 250v PulseX - Metallized Polypropylene Film Capacitor $1.79 $3.58 68µF 250Vdc PulseX Cap 2 68.0μF 250v PulseX - Metallized Polypropylene Film Capacitor $15.06 $30.12 Subtotal $38.46 Shipping $6.97 Tax 0.00 Total $45.43 Erse PulseX CapacitorsERSE’s Pulse X caps are an audiophile grade capacitor designed for quick transient response and ultimate musical performance. Every attention to detail was put into the PulseX capacitor line to insure excellent performance. A premium grade of “defect free” aluminum metallized polypropylene film was chosen from an industry leading film supplier. Specially designed German winding machines with tension feedback control allow for precision repeatability during manufacturing. This industry first technique allows us to virtually eliminate mircrophonics and obtain a tight ±3% tolerance, with virtually no scrap. PulseX quality continues; all leads are lead free (RHOS Compliant), oxygen free 99.99% pure copper. Each lead is attached to the body of the capacitor with ultrasonic welding. To further reduce equivalent series resistance and improve long term reliability , the leads are then soldered with lead free silver solder. PulseX caps are then wrapped in flame proof polyester tape and the ends are epoxy filled. Before final packing, each PulseX cap is tested with certified premium quality Wayne Kerr capacitance bridges to insure a ±3% tolerance centered on the nominal value. Total harmonic and IMD distortion and phase distortion are virtually immeasurable, while all losses are near zero in every aspect. Features: Short body – quick transient design Welded and hand soldered leads Very Low Dielectric absorption factor Very Low dissipation factor Very Low ESR Very Low Inductance Very High Insulation Resistance Excellent Reliability Excellent handling of high current audio pulses RoHS Compliant Construction: Dielectric: High purity polypropylene film Construction: Short body quick transient design Coating: Polyester tape wrapped with high dielectric epoxy fill Electrodes: High purity aluminum vacuum deposited Winding: Bifilar metallized film Leads: Lead free tin plated oxygen free pure copper RHOS compliant Specifications: Tolerance: +/- 3% centered on nominal value Dissipation Factor: .001 to .0001 (see details) ESR: Very Low Dielectric Absorption Factor: <= 100,000 MÙ Temperature Range: -25C to 85C Rated Voltage:MPT25 = 250Vdc/150VacMPT40 = 400Vdc/250VacMPT63 = 630Vdc/400Vac Dielectric Thickness: MPT25 = 4µm MPT40 = 5µmMPT63 = 6µm Metal Layer Thickness:MPT25 = .03µmMPT40 = .04µmMPT63 = .02µm Are the performance differences of these caps measureable? There are a lot of ways that caps are measured beyond capacitance, and many of these are easily and routinely measured. Some common measurements are dielectric constant, ESR, DF, self inductance and temperature ratings. Less tested but other known differences might include the thickness of the dielectric, the thickness of the conductive film, composition of the material used as the dielectric and the film, termination methods and materials used.It the standard measured areas, the Erse PulseX caps very quite well, but this is not where the main audible differences lie.Two caps might measure very much the same in many ways, but one might use Tin foil while the other uses Aluminum foil as the conductive material, and they might have a considerable different character to their sound. Why use a 'by-pass cap'? Think of a capacitor as an energy storage device. Capacitors will store and release energy and are often used for that very reason. In the loudspeaker application though we are wanting to use them for the capacitive effects and not their energy storage capabilities. The larger the cap the more energy it can store. Also larger caps take longer to charge and to discharge this stored energy. Different types of caps store and release energy at different rates too. For instance electrolytic caps are more known as being fairly slow to charge and discharge compared to other types of caps. However they are much less expensive and are often used in loudspeakers especially if large values are needed. Polypropylene caps like those used in many speakers are a faster cap. Not all poly caps are the same though. The really good ones (Erse, Sonicap) are considerably more expensive than the more commonly used types. When an audio signal is sent through a cap there is a small amount of lag time from change to discharge. Often with larger caps, even after they are discharged there is still a small charge that is left as it did not completely discharge. The smaller values typically used in speakers like AV123's x-ls are not too bad. But there is still always some signature to the caps in the signal path. The audible effect is a smearing of the music. Notes will have a little trailing edge to them that blend into the next note. Again the larger the cap value the greater this effect. By-passing the caps on the board with a fast discharging cap like 0.1uF (really small value) Sonicap Gen II will effectively short the larger cap out. The capacitance is hardly changed but shorting the larger cap with the small one will discharge it very quickly. What is does to the sound is reduce smearing. Music is cleaner with more dead space between notes. Many audiophiles refer to this as Blacker Blacks. Upper level detail and resolution is notably better as well. 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