DavidR Posted November 12, 2019 Report Share Posted November 12, 2019 I finally got around to recapping my 90's. Originally I was going to do them with film but with talk of some members having sonic issues with film and my acquiring some AR9's that will get the film caps I decided to do them like I did my AR10Pi. . I had some Solen 400V film that I purchased long ago for the 350uF but they were too big to properly install so I ordered some Bennic NPE. I also replaced the 6 ohm resistor on the UMR and the 1 ohm on the woofer zobel circuit with Mills. Quote Link to comment Share on other sites More sharing options...
Stimpy Posted November 12, 2019 Report Share Posted November 12, 2019 All NPE's, with bypass caps on the series capacitors. A cost-effective recap. Any thoughts on sound, now that the job is done? Similar to your 9's or 610's? Quote Link to comment Share on other sites More sharing options...
lARrybody Posted November 12, 2019 Report Share Posted November 12, 2019 Mills resisters are very good. 1% tolerance and excellent leads. They are getting pricy though. Parts Express now has them at $6.79. Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 12, 2019 Author Report Share Posted November 12, 2019 1 hour ago, Stimpy said: Any thoughts on sound, now that the job is done? Similar to your 9's or 610's? They were sounding very dull. When I hooked one recapped 90 up to my son's system with a TSW610 on the other channel. I felt the 610's tweeter was better. The mids/UMR/LMR of the 90's has the most improvement. I moved both to my system last night and the tweeters seemed to open up some. However, I'm wondering if my tweeters have some drying ferro-fluid. I'm contemplating getting another pair of the Midwest tweeters. It's only a matter of time before the ferro-fluid is hard. I ordered some 150 and 200uF Bennic NPE this morning. The far lead of the 6uF is bitch to solder. Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 12, 2019 Author Report Share Posted November 12, 2019 56 minutes ago, lARrybody said: Mills resisters are very good. 1% tolerance and excellent leads. They are getting pricy though. Parts Express now has them at $6.79. Yes, very good. You did a great job on your 91s. Parts Connxtion has them for under $5 at the moment. Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 12, 2019 Author Report Share Posted November 12, 2019 I ran pink noise signal thru them last night for a couple hours. Today they sound GREAT. The dark veil has been removed. They've really opened up. The twinkle is back in the tweeters. Some pictures to follow soon. Quote Link to comment Share on other sites More sharing options...
AR surround Posted November 13, 2019 Report Share Posted November 13, 2019 6 hours ago, DavidR said: I ran pink noise signal thru them last night for a couple hours. Today they sound GREAT. The dark veil has been removed. They've really opened up. The twinkle is back in the tweeters. Some pictures to follow soon. Nice! Glad that you like the sound. What kind of sources have you been using? Any manipulation of the attenuation switches, or are you listening to them "flat"? And you know that I've been waiting since January 2017 for you to do this recap. LOL Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 13, 2019 Author Report Share Posted November 13, 2019 Sources: CD thru balanced connectors, CD thru tube buffer w/ RCA connectors, vinyl. Still need to do the tuner and my vacuum tube CD player and cassette. I tend to never use the attenuation switches; especially with the amp I'm using now. Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 13, 2019 Author Report Share Posted November 13, 2019 Got some pics: I had to deal with this mess in the first speaker before doing anything else. Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 14, 2019 Author Report Share Posted November 14, 2019 Anyone with AR90's think the woofer magnets are rather dinky like I do ? Quote Link to comment Share on other sites More sharing options...
AR surround Posted November 14, 2019 Report Share Posted November 14, 2019 1 hour ago, DavidR said: Anyone with AR90's think the woofer magnets are rather dinky like I do ? Yes, they are dinky compared to those on the 12" woofers in the AR9. But they do seem to get the job done anyway. Quote Link to comment Share on other sites More sharing options...
lARrybody Posted November 14, 2019 Report Share Posted November 14, 2019 When I got my AR12's they had generic replacement woofers. Talk about dinky magnets, but they sounded decent. They were replaced with the correct 200004-2 woofers. Here they are next to each other. Generic weighed 2 lbs 2 oz and the AR weighed 4 lbs 1 oz, almost twice as much. Quote Link to comment Share on other sites More sharing options...
DavidR Posted November 14, 2019 Author Report Share Posted November 14, 2019 27 minutes ago, lARrybody said: Generic weighed 2 lbs 2 oz and the AR weighed 4 lbs 1 oz, almost twice as much. YIKES ! Quote Link to comment Share on other sites More sharing options...
lance G Posted November 24, 2019 Report Share Posted November 24, 2019 (edited) (Following further posted, as should have been originally, in "AR 9.Basic re-capping advice"). Thanks for all the help and suggestions from everyone. All done (both speakers) with Mundorf E-Cap plain (other than the 2500uF and 470uF on the woofer circuit). Unfortunately I am not sure I like what I am now hearing. I have tested all the original sub 20uF Elcap cap's which were removed, of note the 80uF were of PYE (AR9EK, UK assembled speakers?) manufacture, (my multimeter cap testing facility only goes up to 20uF) and they all seem to be within tolerance. I think I preferred the original sound before I changed out (nearly) all the cap's. The choice of Mundorf was to try to keep to as close to the original specification as possible. The change was thought potentially wise due to the age of the original cap's. The speakers were, when they came to me, apparently in somewhat remarkable condition for their age, I think week 34 1980 is marked on at least one woofer, and the crossovers were original with no physical signs of leaky cap's. Observations please most expert chaps ! Edited November 24, 2019 by lance G Posted somewhat in error. Quote Link to comment Share on other sites More sharing options...
AR surround Posted November 24, 2019 Report Share Posted November 24, 2019 1 hour ago, lance G said: (Following further posted, as should have been originally, in "AR 9.Basic re-capping advice"). Thanks for all the help and suggestions from everyone. All done (both speakers) with Mundorf E-Cap plain (other than the 2500uF and 470uF on the woofer circuit). Unfortunately I am not sure I like what I am now hearing. I have tested all the original sub 20uF Elcap cap's which were removed, of note the 80uF were of PYE (AR9EK, UK assembled speakers?) manufacture, (my multimeter cap testing facility only goes up to 20uF) and they all seem to be within tolerance. I think I preferred the original sound before I changed out (nearly) all the cap's. The choice of Mundorf was to try to keep to as close to the original specification as possible. The change was thought potentially wise due to the age of the original cap's. The speakers were, when they came to me, apparently in somewhat remarkable condition for their age, I think week 34 1980 is marked on at least one woofer, and the crossovers were original with no physical signs of leaky cap's. Observations please most expert chaps ! Try adding 0.01uF or 0.10uF Film and Foil bypass capacitors across the Mundorf E-Caps. These are cheap...on the order of a buck apiece. The shipping will cost more than the caps, so I suggest you by a few of each to see which ones you like. These will get that last ounce of grit out of the midrange. https://www.parts-express.com/dayton-audio-dffc-001-001uf-400v-by-pass-capacitor--027-450 https://www.parts-express.com/dayton-audio-dffc-010-010uf-400v-by-pass-capacitor--027-452 Also, try adjusting the attenuation switches to -3dB on the tweeter and -6dB on the UMR. Keep the LMR switch at 0dB. Let us know how it goes. Quote Link to comment Share on other sites More sharing options...
blanddawg625 Posted July 13, 2023 Report Share Posted July 13, 2023 On 11/12/2019 at 1:16 PM, DavidR said: They were sounding very dull. When I hooked one recapped 90 up to my son's system with a TSW610 on the other channel. I felt the 610's tweeter was better. The mids/UMR/LMR of the 90's has the most improvement. I moved both to my system last night and the tweeters seemed to open up some. However, I'm wondering if my tweeters have some drying ferro-fluid. I'm contemplating getting another pair of the Midwest tweeters. It's only a matter of time before the ferro-fluid is hard. I ordered some 150 and 200uF Bennic NPE this morning. The far lead of the 6uF is bitch to solder. No it is not if you just move the switch board out of the way. This is done by cutting the front lead on the 4uf and removing the nuts from the 3 switches in back. Then it can be lifted slightly and moved, making it easy to reach both connections of the 6uf. Quote Link to comment Share on other sites More sharing options...
DavidR Posted July 15, 2023 Author Report Share Posted July 15, 2023 ..... assuming I had a 'switch board' in my 90s ..... Quote Link to comment Share on other sites More sharing options...
blanddawg625 Posted July 23, 2023 Report Share Posted July 23, 2023 On 7/15/2023 at 1:09 PM, DavidR said: ..... assuming I had a 'switch board' in my 90s ..... So they changed the way the switches are mounted at some point, because the pair I have has them on a board. The switches are on one side and the resistors are on the other. Quote Link to comment Share on other sites More sharing options...
johnfalc Posted July 23, 2023 Report Share Posted July 23, 2023 I wonder when the change was made? My 90s (Serial #s 001752 and 001753) have no seperate switch board. Quote Link to comment Share on other sites More sharing options...
Stimpy Posted July 24, 2023 Report Share Posted July 24, 2023 My 90's (bought direct from the factory, around '81) have the adjustment resistors mounted on a separate board. But, a pair of back up 90 crossovers I have, that I sourced from eBay, have the resistors soldered directly to the switches. Quote Link to comment Share on other sites More sharing options...
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