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How Have You Cleaned Your AR Pots? Chemical Methods? Polishing Methods?


Martin

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In the past, I have always used the chemical method described in the other audio website that suggests using a vinegar & salt solution to clean the copper pads inside the ceramic pots. It has always worked very well for me and produces nice, shiny, conductive, copper surfaces.  I don't think I have ever had to use a physical method, like polishing with a Dremel, after using that particular chemical treatment. It is very easy & effective.  It is, however, somewhat caustic, and is very rough on, for example, wipers that are past their prime, so it probably shouldn't be used on wipers.  

I've read about using Brasso (which is both chemical & then physical when you wipe it off), a polishing wheel on a Dremel, & fine abrasive paper. 

What cleaning methods are your favorites? 

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21 minutes ago, Martin said:

What cleaning methods are your? 

I prefer LPads over original pots;  No cleaning.  I was a pot holdout until forced to change and finally folded completely after the first set worked so well.  When I had pots I used a dremel buffer wheel and deoxit.

 

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Agree with Aadams.  Difficult to stop natural chemical reaction between metals over time.  Encourage you to replace with new, whether they are pots or L-pads.  And I have refurbished 3 early AR series pots, all worked perfectly for a year or two.  I now just replace.

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I have used a Dremel tool with a small round brass brush. Over time I also came to the conclusion that I was wasting my time. There is not much you can do about pitted out disk and wipers. The L-pad or replacement pots are the way to go. Years ago I saw some solid state pots using small resisters and a rotary switch. Does anyone have information about these?

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I'm about to restore my AR-3as and would love to keep things original, except for caps, of course.   I get the vibe that the vinegar & salt bath is not viewed too favorably.  I've used that method on 2aX, 4X, 5, etc. & always had good results except when the solution consumed an already degraded wiper.   Any chemists out there?

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1 minute ago, Martin said:

I'm about to restore my AR-3as and would love to keep things original, except for caps, of course.

If your 3as have Compulytics you can leave them in place and replace the pots with new pots or LPADS. The "vibe" is old pots are not viewed favorably but you will not be admonished whatever you do.  The only original pots that still have a good rep were on early model ARs and they had all brass internals as I recall reading. The RoyC LPAD mod or the recent model pots that are offered by a couple of sellers are the favorites.

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Some original pots I cleaned up five years ago for some AR2ax's. After three plus years they started getting drop-outs. Subsequently  they have been replaced with L-pads.

EAblXLR.jpg

L-pad installed in a AR4x crossover. This is not my picture or work. You can get these from suppliers like Parts Express and Madisound. 

5gWkacL.jpg

On the left is a Ohmite RHS15 R and some ceramic  potentiometers currently available on ebay and from others. They are electrically identical to the original aetna-pollack pots but far superior in construction and function.

lep7V5d.jpg

The AR3a restoration guide covers this subject in great detail.

http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/

 

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