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r_laski

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  1. I am going to try to answer both of these posts with my recommendations. Thank you for the compliment thezone999. Sorry for not answering sooner. Hope you are still on the forum. 1. Did I replace the coils? No I used the originals. These are very good quality air core inductors. Replacing all of them was outside of my budget. However, as much as possible, I oriented the inductors in different planes from each other to reduce cross-talk between them. That is why they are not all mounted flat on the boards. Parts I replaced: all capacitors, 6 Ohm resister, all wires from crossover to drivers, binding posts, and the front speaker cloth (side woofer speaker cloths were still perfect). I mounted each crossover on four separate pieces of pegboard. One pegboard for each driver. 2. How long did it take you? Short answer, it took about 5 months. Longer answer: About 4 months to read through this forum; research capacitor combinations from various capacitors retailers; build spreadsheet of cost of various combinations from the retailers; and purchase all the parts. One month to layout the boards and assemble the first one to test against a “stock” AR9, assemble second crossover, and install. 3. Replacing, just the capacitors on the existing boards and leaving everything else intact. My recommendation to do this would be to remove all the existing capacitors and replace them with MDL nonpolar electrolytic (NPE) capacitors. You can get these from Parts Connexion, Madisound, and Parts Express. Parts Express NPE capacitors are supplied by MDL without the brand name printed on them. This is the least costly option for recapping. As Stimpy stated, I list three sources because you will probably have to purchase some capacitors from all three to get all single capacitors or combinations of capacitors (that you parallel together) for all the capacitor values needed. For example, Madisound is the only one I know of that sells 1000mF MDL capacitors. I parallel 2 of these with a 500mF capacitor to replace the 2500mF woofer capacitor. You can parallel a 220mF and 250mF capacitor for the 470mF woofer capacitor. This is the combination I will be using on the woofer crossovers for my second pair of AR9s. 4. How much did it cost? Some of the small hardware parts I used I had left over from AR-LST, AR11 and AR90 crossover rebuilds I did many years ago. So I can’t give a total cost. Also, whatever I bought from Parts Connexion, was during one of their 25% off on almost everything sales. I’m not sure if or when they will have another sale like that. Prices have gone up since I purchased in 2019. I can give a ballpark total cost of between $400 and $425 for everything I purchased for both crossovers, including shipping and sales tax. For me to build crossover boards, you would need to remove and send me the crossover boards intact or send me your speakers with just the crossovers installed. If you can solder, and are only going to replace the capacitors, it is a doable DIY project without removing the boards. Many YouTube videos that can teach you how to solder. NJtechguy, the capacitors in AR90 and AR9 crossovers are very similar. Stimpy’s reply to your post has excellent information and recommendations. AR Surround also has excellent recommendations on capacitor combinations. Since you posted on my thread, I will give my recommendation, based on my recent AR9 recap project. To keep cost reasonable, use MDL NPE capacitors for the 350mF woofer capacitor. I would use ClarityCap poly film caps for all the other capacitors. I use different series of ClarityCap capacitors for series (inline) and parallel (shunt) capacitors. 4mF (series) ClarityCap CSA (2) 2.0mF 630VDC connected in parallel. 6mf (series) ClarityCap CSA (2) 3.0mF 250VDC connected in parallel 8mF (parallel) ClarityCap PX 4.7mF and 3.3mF 250VDC connected in parallel 24mF (series) ClarityCap CSA (2) 12.0mF 250VDC connected in parallel 30mF (parallel) ClarityCap PX 30mF 250VDC 40mF (parallel) ClarityCap PX 40mF 250VDC 80mF (series) ClarityCap (2) PX 40mF 250 VDC connected in parallel I use ClarityCap PX for the 80mf series cap to keep total cost within budget. If cost was no object, I would parallel ClarityCap CSA 47mF and 33mF 250 VDC caps. All of these are available from Parts Connection. You can reduce cost by using single “close” cap values 3.9mF, 5.6mF, 8.2mF, and 22mF depending on how particular you are to matching designed cap values precisely. I add small value film bypass caps to the AR9 woofer caps. If you decide to add bypass caps these are a matter of personal preference as to what you use.
  2. I've posted this AR9 crossover diagram here and in my post/threads of my AR9 recap/upgrade. I've added the second 1.37mH inductor coil to the UMR section. See https://community.classicspeakerpages.net/topic/11407-my-ar-9-capacitor-recapupgrade-project/ my 12/3/2020 post for picture and details. It looks like the AR90 UMR section drawings in earlier posts on this topic have the same second inductor coil wired the same way.
  3. I'm posting this AR9 crossover schematic and picture to show there is a second 1.37mH (6) coil in the Upper MidRange (UMR). It is the one to the right in the picture. One (outside) wire is connected to the 24uF cap and 0.2mH coil. The other (inside) wire is connected to the upper black (-) binding post. The other 1.37mH (6) coil is on the lower left corner. One wire (outside) is connected to the 0.2mH coil, orange wire to UMR (+), and 8uF cap. The other wire (inside) is connected to the 6 Ohm resistor, as shown in the schematic (resistor not in the picture).
  4. This is an AR9 woofer and Lower Mid Range (LMR) crossover section picture and AR engineering drawing of same. in the picture, the 80uF capacitor (gray) is on the lower right corner. As you can see, the purple wire comes from the attenuation board to one pole on the 80uF cap. The 2.63mH (13) coil is attached to the other 80uF cap pole. The other end of the 2.63mH coil, one pole of the 30uF capacitor, and white wire are attached at a single point. White wire connects to the (+) terminal on the 8" LMR. The green and brown wires are connected to the other end of the 30uF capacitor. The green wire goes to the (-) terminal on the 8" LMR. The brown wire goes to the upper black (-) binding post. The AR9 crossover schematic is correctly drawn in how the AR9 LMR crossover is wired. It is NOT wired the same as the your AR90 LMR crossover picture or drawing. Hope this helps clear up the difference between the AR9 and AR90 LMR wiring.
  5. I purchased all the Clarity Caps (and the “defective” Ecaps) from Parts Connexion. For my other pair of AR-9s I am leaning toward purchasing matched pairs of single caps where possible vs DIY assembling matching pairs of 2 caps paralleled together. Just have to get over exactly matching original crossover cap values. I purchased matched pairs of 470uF ECaps from Sonic Craft. I received exactly matching caps within 1% of rated value. Yes we are. For both exactly matching original capacitor values and tolerances between speaker crossovers. I think we solved the same problem differently with equally acceptable results. I replaced Dayton caps with Solens. You kept the Daytons and replaced the Solens with Ecaps. I suspect Daytons and Solens don’t mix well together. Like I said, I believe different brands of capacitors do not always mix well together. That would be a daunting task to do all at the same time. The research time, purchasing parts, prototyping the first crossover, initial testing vs stock AR-9, and building and installing crossover in second AR-9 took about 3 months. I still have a pair of AR-9s to do. If you are happy with what you have already done to your AR speakers there is no need to redo them. Yes, exactly!
  6. Thanks to all of you on your compliments. >>I particularly had problems using poly caps in the 24uF series spot on the UMR and eventually went with Mundorf ECaps bypassed with 0.01uF F&F caps.<< >> Yes, as many of you recall, those Solens ? beat me into submission!! << I read your AR-9 posts while preparing for my project. I actually purchased Mundorf 22uF and 1uF ECaps (couldn't find a 2uF) for the 24uF UMR and was going to experiment with them. However, when I measured new 22uF ECaps they measured 23.8/23.9. That’s almost 9% over rated value. It should be no more than +/- 5%. I never used them. I purchased two pairs of 470uF ECaps for woofer crossovers from a different source. I paid extra to have these precision matched. I received exactly matched pairs. The second pair is for when I rebuild the crossovers of my remaining pair of stock AR-9s. I had a similar experience of capacitor disaster with a pair of AR-90s. I reread a thread on a pair of AR-90s I worked on 16 years ago. I tried a combination of Dayton, Solen, and North Creek (no longer available) poly caps. It was very unpleasant, unlistenable. I replaced the Daytons with Solens and all was well. My point is different brands of capacitors do not always mix well together. So far same brand Clarity Cap CSAs and PX series work perfectly together in these AR-9s. The MDL and Ecaps combination in the woofer crossover also work extremely well together. My take on bypassing – I’ve read many views about bypassing. I bypassed the electrolytics in the woofer crossover with Clarity CSA poly caps. I chose this based on a similar practice by a company that rebuilds crossovers, mostly for classic Polk Audio speakers. They do not bypass Clarity Caps, so I also did not. There is one thing I wish someone would research about bypassing. Is there a formula for an optimum ratio of bypass capacitor value to “primary” crossover capacitor value? I’ve seen the recommendations for .01uF up to a certain capacitor value and 0.1uF above that. I’m not sure how much affect a 0.1uF capacitor has on a 2500uF or 470uf capacitor. Not going to remove them, just something to ponder. >> I too will be curious as to what you think of your "new" AR9's after you've listened to them for a while. << I've got more than 30 hours of listening to these "new" AR-9s. So far I am VERY PLEASED. I'm running them with all switches at 0dB. I haven't heard any need to "fiddle" with them. I will post any changes to my listening impressions as I spend more time listening. At most, I expect them to “warm up” only slightly more over time. There is one “improvement” in how these AR-9s sound that is worth mentioning. It’s related to speaker placement, listening position, and listening room acoustic characteristics. My listening room is a multipurpose room – separate audio and TV (no home theater). My stereo system is along one of the long (wide) walls, TV along a short (narrow) wall. I’ve placed the AR-9s as close to recommended in the owner’s manual as possible. My normal listening position is centered between the speakers seated against the opposite wall. The “sound stage” is very good in this position. However, if I move about 2 feet forward the sound stage really opens up. It appears to move a little forward toward me, but, more so it extends beyond the walls behind the speakers. Side to side it extends past the speakers to the corners and side walls of the room. Imaging, by that I mean separation and placement of individual vocalists and instruments, is much improved. This appears to be an acoustic sweet spot in the room. >> I like the CSA Clarity caps, too. I didn't think 'break-in' took all that long. However, I played pink noise thru them for about 8 hours. Also, I use a 3.9uF and not 2 x 2uF. << I considered both options. A single 3.9uF cap is probably just as accurate to replace a 4uF cap and a lot less costly. 2x2uF is just my personal preference. I may go with single caps within 5% of desired value, where possible, in my second pair of AR-9s.
  7. It’s been a long time since I posted on this forum. After several years without an audio system my better half urged me to replace whatever needed replacing and get back to enjoying my music collection again. I have two pairs of AR-9 speakers. I am using one pair of these in my “new” audio system. I knew part of my system rebuild would be recapping a pair of AR-9s. I spent a several days on this forum reading every thread I could find on what you all have done with your AR-9s. Thank you all for the wealth of information. I found it helped me develop a plan for recapping my AR-9s. Years ago I downloaded and saved all the AR-9 engineering drawings that were posted at the time. Glad I did as I couldn’t find them again on this web site. I also spent considerable time researching various types (electrolytic/film), brands, and sources of capacitors. I also found some valuable information on a few crossover component sellers’ websites / links. Below is a rundown of my project. Scope/Considerations: Some things I considered for the AR-9s: 1. Internal or External crossover. I decided to keep the crossover internal. There is only a minor change to how it is configured. Each Crossover section remains as originally laid out but is built on a separate pegboard. 2. What crossover parts to replace / retain. I decided to reuse all inductors and left the switch board as is. I replaced all capacitors, 6 Ohm resistor in the upper mid-range (UMR) crossover, binding posts, and all internal wiring. 3. Capacitor selection. Due to size and cost, woofer crossover capacitors are electrolytic with film bypass capacitor. All other capacitors are film capacitors (details below). I replaced the original wires with color coded 16 gauge tinned copper wire. 4. Cabinet changes. The cabinets are in such great shape I left them as is. The only “modification” was removal of plastic Velcro dots on tweeters and upper mid-range drivers and cabinet. I did not remove the original crossover backboard. 5. Drivers. Years ago I re-foamed all the 12” and 8”drivers in both pairs of AR-9s. The foam surrounds are still in new condition. Thanks to the speakers being boxed up or covered up while stored during a long period of non-use . I attached adhesive backed gasket tape to all drivers prior to reinstalling them in the cabinets during final reassembly. Crossover tear down: I removed nuts securing woofer/Lower mid-range (LMR) crossover boards removed them intact. This one had the small axial 470uF capacitor. The other AR9 had the large 470uF radial can capacitor. Before removal of any component from a board I took many pictures and labeled what each wire inductor lead and capacitor lead was connected to. I removed everything on the UMR/High Range crossover board without removing the board from the cabinet. Then the worst task of the entire project – removing hot glue from all inductors. Original capacitors measurements: I used the same basic capacitance meter I used when I recapped my AR-11s years ago. It tests at a single frequency, but for me that is enough to indicate whether a capacitor is in or out of specs. Below is a chart of capacitor measurements from both AR-9s in this project. Capacitor AR9K013212 Dif % AR9K013494 Dif % 2500 2250 -250 -10 2330 -170 -6.8 470 576 +106 22.6 510 +40 8.5 80 106.4 +26.4 33 151 +71 88.75 40 48.1 +8.1 20.25 40.7 +.7 1.75 30 50.5 +20.5 68.3 65.4 +35.4 118.0 24 33.0* +9.0 37.5 27.1 +3.1 12.9 8 9.31 +1.31 16.375 8.79 +.79 9.875 6 5.94 -.6 10 5.57 -.43 7.17 4 4.07 +.07 1.75 9.25 +5.25 131.25 * Capacitor reading was unstable, continuous changing. No doubt in my mind new capacitors would improve these AR-9s. Only one capacitor in each speaker measured within my threshold of within +/- 5% or rated capacitance. I spend a considerable amount of time deciding what capacitors to use for this rebuild. I considered capacitors I used for AR-LST, AR-11 and AR-90 recaps in the past, what others in this forum used, and what capacitors are being used and recommended by professional crossover builders/re-builders. I made several cost comparison spreadsheets of capacitor brands from various sources. I benefited from a 25% off seasonal sale on all the film capacitors I chose. It took purchases from 4 different sources to get all these capacitors. I decided on the following combination of capacitors: 2500uF - M.D.L. (Jantzen) (2) 1000uF and (1) 500uF electrolytic bypassed with 0.1 uF Clarity Cap CSA 630VDC film. 470uF - Mundorf E-Cap AC Raw electrolytic (matched pair) bypassed with 0.1 uF Clarity Cap CSA 630VDC film. 80uF - (2) 40uF Clarity Cap PX 250VDC. 40uF - 40uF Clarity Cap PX 250VDC 30uF - 30uF Clarity Cap PX 250VDC 24uF - (2) 12uF Clarity Cap CSA 250VDC 8uF - 4.7uF + 3.3uF Clarity Cap PX 250VDC 6uF - (2) 3.0uF Clarity Cap CSA 250 VDC 4uF - (2) 2.0uF Clarity Cap CSA 250VDC Note: Woofer capacitors are electrolytic bypassed with 0.1uF film. All other parallel capacitors are Clarity Cap PX film to save cost. All other series capacitors are Clarity Cap CSA except for 80uF LMR series capacitor. PX was selected to save cost. At the sale prices, the Clarity Cap film caps ended up costing about the same as a regularly priced set of Solen film capacitors would have. Prototype: As I stated above, I built each driver’s crossover on a separate pegboard. Preliminary layout Final layout - Holes in 4 corners of woofer pegboard match up perfectly with mounting studs in bottom of cabinet. Homemade bus bar of 14 AWG tinned copper. On the second AR-9 crossover I stacked the 500uF cap on top of the two 1000uF caps to reduce space and moved the bus bar over. This enabled me to move the entire layout down one row of holes and still have the corner holes open for the mounting stud in the cabinet. This also gave me more space between this board and the LMR board mounted behind it on the back of the cabinet. Crossover from second AR-9 (big can 470uF) and new woofer crossover - I tried to orient inductors in different planes as much as possible on each board and across boards. Original AR-9 LMR section (lower left quadrant) and new LMR crossover. The new board is mounted to the back of the cabinet below the UMR (original backboard). Woofer and LMR boards mounted in cabinet. Best effort to orient inductors in different planes between the two boards. UMR and High Range (tweeter) capacitor pegboards. UMR is built around original binding post holes. One side of pegboard holes had to be enlarged for all binding post holes to line up. UMR and tweeter boards in cabinet. Close-up of tweeter and top of UMR pegboards. One blue wire on tweeter board goes to tweeter. Second blue wire goes to black (-) binding post. Originally inductor and blue wire were connected directly to black (-) binding post. Wires: With few exceptions I kept all new internal wires the same length as the original wire lengths. However I changed some of the wire colors for convenience/ standardization. All woofer section wires were red (+) / black (-). I changed the wire from the upper red binding post to the switch board from white to gray. I kept the purple wire color from the switch board to the 80uF cap on LMR crossover. All other LMR wires were white (+) green (-). All UMR wires Orange (+) brown (-) All tweeter wires yellow (+) blue (-). Final assemble and testing - While I was working on the project AR-9s, I hooked up my other pair of AR-9s to my new audio system to “break-in” the new components and establish a subjective baseline of what an original pair of AR-9s sound like. I have to say, not knowing the actual condition of the capacitors in this pair the sound was very good. However, “s”, “t”, “st” harshness was very evident. I also had to switch the UMRs to -3db to tame its overpowering the other drivers. After reassembly I replace the left original AR-9 with recap project AR-9. All switches on the recapped AR-9 set to 0db. No burn-in. Just put some music on and subjectively listen. Immediately there was a noticeable difference between the left and right speakers. The left was a little louder, MUCH cleaner. The original AR-9s sounded pretty good by themselves. Compared to the recapped AR-9 however, my impression was the original AR-9 was now somewhat “fuzzy”. They sound between the two speakers was unbalanced. Putting the UMR switch on the original AR-9 to 0db balanced the output somewhat. But, it did not improve the difference in clarity (no pun intended). I rebuilt the second AR-9 crossovers making minor changes in the layout. One significant change I made was to glue machine screws to the spacer boards. I put spacers under the crossover pegboards to provide space under the pegboards for the cable ties that secured the capacitors and inductors. Now all crossover boards are secured with screws, washers, and nuts and can be removed. Only the spacers are glued to the cabinet in this AR-9. Listening with both recapped AR-9s hooked up: I’m not a GESR (golden-eared stereo reviewer). All I can say is I’ve never owned an audio system that sounded this amazing! I remember when we were recapping AR-11s, AR-90s and LSTs. We would describe the improvement as being as if a veil had been removed from in front of the speakers. This is more like a heavy curtain has been removed. Female and male singers sound like they are standing in front of me in the room. Background vocals are distinct from the lead singer. There is air and space between instruments and around each instrument. As familiar as I thought I was of my music collection, and I can’t believe I’m saying this, I heard things I never heard before in the music.
  8. >>Rich, did you notice if any of the woofers with aluminum voice coils were black anodized on the inside?<< I've refoamed five (5) AR-11 "B" and twelve (12) AR-9 200003 woofers over the past few years. All with the silver flange. I'm a "shimmer" when I refoam so I saw the inside of the voice coil on all of them when I removed the dust cap. The Aluminum VC formers on all the woofers were all silver, none were black anodized like the one in your pictures. The same can be said for all the 10" woofers (pair of AR-90's) and 8" lower midranges (AR-90's and AR-9's)I've refoamed -- all silver Aluminum VC formers. Rich
  9. >>It appears that the late-70s designation of the 200003/1210003 woofer (AR-9/AR-11B) you show is consistent the advent of the aluminum voice-coil former.<< Tom, I believe you are right about when AR changed from Nomex to Aluminum voice coil formers. When AR changed the ADD line from what we on the forum have referred to as "A" model ADD speakers -- Brass logos, White/yellow fabric on tweeter, black screen on midrange... The 200003 woofer was the same as that used in the AR-3a and AR-LST -- Black flange, wide masonite ring, hex screws... I have my Dad's AR-11 "A's" here with me. I just pryed up a small portion of one woofer dust cap (a replacement porous dustcap installed by a shop he had refoam the woofer for him, it isn't glued down very well) -- Nomex VC former, just like the AR-LST woofers I refoamed a few years back. All the AR-11 "B", and AR-9 200003 woofers I've refoamed are the silver flange version -- all have Aluminum VC formers. Pretty good indication this is when the change from Nomex to Aluminum was made. >>One way to help in removing the glue on the woofer flange is to use denatured alcohol to soften the glue, and then carefully scrape away.<< Just to add my techniques -- I've used "Goof Off" and Isopropyl alcohol to loosen the glue. The alcohol works better than the Goof Off. I use Q-Tips saturated with alcohol to "scrape" the foam remnants away before going after the glue. The best tools for scraping the glue from the masonite ring and the outer edge of the cone are razor type knifes -- X-acto, Stanley retractable blade knife, Box cutter/Wallpaper razor knife with break-off blades. Whatever type knife you use, use the BACK OF THE BLADE (not the sharp edge) to scrape. You will not cut the cone or damage the masonite when you use the back of the blade. >> It's slow, laborious work, but a clean surface is mandatory for good results.<< Absolutely. Rich
  10. >>Enquiring minds can't wait to find-out.<< Bret, I transported the AR-90s from Atlanta to Omaha two weekends ago. I also delivered the pair of AR-LSTs that my brother bought over a year and a half ago and had never seen or heard. The LSTs were unwrapped and hooked up first. Unfortunately, my time in Omaha was cut short, so we did not have a chance to hook up the AR-90s while I was there. Peter will post his listening impressions as soon as he can. >> Would you clarify what was finally done? I think I understand that the inductors and resistors in the 90s were NOT replaced. Did I get that right?<< Yes. The crossovers were rebuilt using the original inductors and the two resistors not in the equalization (attenuation) network. This network was removed and the switch holes filled with black plastic plugs. All wires were replaced – 14 AWG to lower mid, upper mid and tweeter; 10AWG to woofers. All capacitors were replaced with either Solen or North Creek metallized polypropylene caps. Rich
  11. >>Some say capacitors don't wear in or break in, and I have to admit that I was in that camp myself not that long ago. All I can say is that the sound has altered just a bit as the new parts settle into their new home.<< Richard, So, instead of reforming your AR-90s, you have corrupted them, turning them to a life of crime to go out and commit speaker break-in. ;-) When I rebuild crossovers I try to play them as much as possible every day for a week to let the new capacitors “set their bias” (North Creek’s terminology) and settle in. This is part of my listening test routine for “prototypes” and after final installation of rebuilt crossovers. The Zen caps are non-polar, but directional. They have a preferred orientation with different color leads to designate “input” and “output.” Haven’t seen or read this about Solens. I hope you are finding, as I have, the speaker’s change in sound over time is one of improvement. It gets richer, even more detailed, and deeper (more ambiance). I played the AR-90s yesterday and it was like there was a whole new dimension to the speakers. Time for these AR-90s to go back to their owner for final evaluation. Rich
  12. >>I meant to say in my previous post that I bypassed Solens with Audio Caps for the upper and mids. Actually it is more like paralleling them, using a 3.9 Solen and a 0.1 Audio Cap to make a 4uF. I did similar for the rest, trying to match the factory values as closely as possible. The distinction between bypassing and paralleling still evades me. << In one of my posts above, I referenced a web site that describes bypassing. Basically, bypassing is done by paralleling capacitors. But, all paralleling of capacitors is not bypassing. Paralleling a 3.9uF Solen and a 0.1 AudioCap is bypassing. In bypassing, you are paralleling a large (3.9uF) metallized polypropylene cap with a much smaller (0.1uF) film and foil capacitor. Additionally, your bypass capacitor will have a higher voltage rating than the larger capacitor. Rich
  13. >>I have to politely disagree on replacing the caps in the woofer section. I used a 100uf and 150uf Solen cap to get the correct value, and the improvement in the bass response is almost beyond description. I'm not used to feeling the pressure of the pedal drum at low wattage hit me in the chest like it does now. (Sorry, I just couldn’t resist, LOL) *I had my daughter participate in a “blind” listening test when I was testing the first prototype crossover with the Zen caps in woofer section, Dayton caps in lower mid, and Dayton caps with Solen 24uF in upper mid and with 6uF Zen in tweeter circuit. Against the stock AR-90, she picked the stock AR-90 as better – except for the audibly better bass response in the prototype. She more or less confirmed what I heard. For me, sometimes the stock speaker was better, sometimes the prototype, except the prototype always had better bass. The Solen / Zen crossover was clearly superior sounding to the stock speaker in all areas. Since Robert stated he is “upgrading” his AR-9 crossovers, the points I was trying to make: 1) Although there is a significant improvement in bass response by replacing the woofer caps, it comes at a significant cost (over 50% of the total) relative to replacing all the other caps in the crossover. It will probably be a much higher percentage of the total in the AR-9 because of the much larger cap values involved. As an example: you buy two 200uF and 270uF Solens from Percy Audio to parallel in pairs to get 470uF caps. The cost is over $220 with shipping. I haven’t even determined a price for the 2500uF caps, but you can see the cost is already substantial. 2) I do not advocate upgrading (tweaking) by replacing perfectly good OEM caps. However, I do believe what I have read about capacitors, in particular electrolytic capacitors. While they may not “fail,” they do degrade over time and eventually need to be replaced. I also believe you and I have confirmed there is some validity to this by testing the capacitors in several speakers. 4) The only way to objectively know if your caps are degraded to the point where they are out of tolerance or significantly mismatched and are affecting the performance of your speakers is to test them. You cannot use age alone, a subjective measurement in this situation, to determine the “health” of your capacitors. Rich
  14. Robert, I have not rebuilt an AR-9 crossover - yet. The AR-90 crossover does not have 2500uF or 470uF caps. I can tell you that “rrcrain” and I had to parallel two or more caps to get the 350uF value of the woofer capacitor for our AR-90s. I had one bad 350uF cap and the other one was marginally within tolerance. I replaced them both to restore the woofer crossover back to the original spec - 350uF. If you have to replace the 470uF cap you will almost certainly have to parallel some caps to get the correct value. Have you tested the caps and are they degraded / out of tolerance / leaking? If they test OK, I would leave them in the crossover. These caps are not easy to find and are going to be relatively expensive to replace. IMO - You spend the most and gain the least improvement by “upgrading” caps in the woofer section. However, if your woofer caps have degraded to the point they are out of tolerance, you will probably want to replace them. >> I decided to go with Solens crossed with Audiocaps for the upper and mids. << Can you explain what you mean by “Solens crossed with Audiocaps for the upper and mids?” Are you bypassing Solens with Audiocaps or just using some Solen and some Audiocaps? Rich
  15. >>I am interested to hear about the results from the AR90s you are currently testing … And indicate what recordings you are using as the listening test.<< After a couple of late nights, I finally finished the crossover rebuild on my brother’s AR-90s. The only way I can describe how they sounded before we started this project is “inconsistent.” Sometimes they sounded OK and sometimes they sounded awful. These were an eBay purchase, so we don’t know the history of this particular pair. Originally, our intent was to keep the cost to a minimum. I reused the coils and resistors. I used a combination of mostly Dayton, with a few Solen, and North Creek Zen caps. I replaced the hook-up wire with the same type I used in my AR-11 project. The attenuation boards were removed. The 40uF Zen cap takes up most of the space where these boards were. When I tested the first prototype against the “stock” AR-90, I was somewhat disappointed with the results. After I had already put the crossover together, Sean posted a message about not using inexpensive (Dayton) caps. Having used some Dayton caps and “hearing” them, I have to say that I agree. I discussed the results with my brother and we decided on a Zen / Solen combination. The Dayton caps were removed and the prototype rebuilt. After a short listening test I was convinced we had the right caps. With both crossovers rebuilt and installed, right away I can tell the sound was significantly improved. There is so much more detail and clarity. A larger sound stage in that the music seems to extend further back behind the speakers, what I call ambiance. The improved detail and clarity, dare I say accuracy, has been described as if a curtain has been removed from in front of the speakers. I believe that description fits here. For listening tests I believe it really doesn’t matter so much what you listen to as it does listening to what you like and are familiar with. I start with Cowboy Junkies’ “Trinity Sessions.” Mining for Gold - no instruments, only Margo Timmins singing. Listen for ambiance, timbre, and clarity. In 1 minute 34 seconds you can tell a lot about your speakers. “Misguided Angel” – right from the beginning of this track if you don’t feel the bass from the kick drum hitting you in the chest your speakers are not performing. Linda Ronstadt’s “Greatest Hits Vol II.” The DCC Gold CD (remastered from original studio master tapes). You get Linda’s full range in “Blue Bayou.” I recently added Nora Jones’ “Come Away with Me” CD to my listening tests. I’ve also added Allison Moorer’s, “Miss Fortune.” For a change of pace, Pink Floyd, “Dark Side of the Moon.” For a quick test, I listen to select portions: Heart beat at beginning, alarm clocks in “Time,” cash registers in “Money.” Fleetwood Mac, “Fleetwood Mac” album, “World Turning.” In the mid to late ‘70s this was THE track almost everyone used to test bass. The dealers just had to pull the grills off the and have you watch the woofer excursion with every beat of the kick drum. Henry Mancini, “Symphonic Soul.” Some orchestral pop music. Listen to bass guitar solo at beginning of “Peter Gunn.” Must be able to hear both the bass guitar and the drum behind it. Mannheim Steamroller, “Christmas Extraordinaire” Want a very quick test track? The first 30 seconds of this CD. This is a representative list of what I used for my initial listening test. Additionally, some Sax/Jazz – Grover Washington Jr. “Winelight” and Male vocal - Marc Cohn, “Walking in Memphis”. Rich
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