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DavidR

RE-cappi my AR90's

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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.

image.thumb.png.e223fea2b6886eae263ba342a3025340.png

 

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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?

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Mills resisters are very good. 1% tolerance and excellent leads. They are getting pricy though. Parts Express now has them at $6.79.  

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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.

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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.

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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.

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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

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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.

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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.

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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.

RdM7X11.jpg

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27 minutes ago, lARrybody said:

Generic weighed 2 lbs 2 oz and the AR weighed 4 lbs 1 oz, almost twice as much.

YIKES !

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(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 by lance G
Posted somewhat in error.

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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.

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