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AR 3 WIRING POTS

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When cleaning the pots should I just wire nut where I have cut? I really don't want to solder inside of a box? How about a butt splice? I'm assuming since the rest of the speakers are in very good shape that the pots are good enough to reuse? If not I have the ones from my 3a's that I replaced with l-pads. So no one answered my capacitor question? After doing a little searching on here I can see why, Because no one agrees lol  I'm going to stick with the polys . Thanks For all your help guys! 

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26 minutes ago, arken said:

So no one answered my capacitor question? After doing a little searching on here I can see why, Because no one agrees lol  I'm going to stick with the polys . Thanks For all your help guys! 

I was wondering if anyone would touch your question.

Your are correct. Nobody agrees.   I think the latest solid advice is replace like for like ---------- If you have NPEs replace with NPEs. 

Pots are not controversial. Wire nuts are ok, especially since you may pull the pots again after you clean and reinstall. You might want to solder a same color pigtail wire to the pot to ease the re-installation.

Adams

 

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My personal belief and practice?

In electronics there is NO connection better than NO connection - period

Maybe for home electrical wiring and the like but not for passing audio signals

I ALWAYS solder electrical connections when doing service and restoration work except where faston types were used by the manufacturer as are commonly found on tweeters

I also do not solder the obvious such as woofer connections equipped with spring terminals, phono cartridges etc where by doing so damage could be incurred, or in instances when no practical provision to do so is allowed for (i.e. some of these terminals involving threaded fasteners and such which I also try to avoid when I have a choice such as upgrading binding posts) Molex connectors et al.

But when a solder lug is provided I use it, or, when I have a choice and never attempt to circumvent those times for the sake of convenience

Too many stories to share as for why I feel this way other than my opening statement which I will always stand by until can't do anything with this hobby any longer

NO connection is better than NO connection - meaning purely mechanical

I realize and understand that wire nuts were, and still are, popular and were a favorite of a lot of makers (and to this day for a great many hobbyists as well) - to my mind that still doesn't make them legitimate in any respect other than it saved them money and time to do so 

Everything in a speaker enclosure should be hardwired in my opinion with the few exceptions noted above 

But no, I do not hard wire my speaker cables to my amps and components : - )  I do have to make a few concessions

Craig

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Well there goes another safe topic.  Who would have thought wire nuts could be heard? (Rhetorical)

Adams

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1 hour ago, Aadams said:

Well there goes another safe topic.  Who would have thought wire nuts could be heard? (Rhetorical)

Adams

I don't think anyone said or implied that you could unless I missed something

For me, it's a matter of maintaining decades of maximum circuit integrity in as many spots as is practical (and less things to clean service and drench with deoxit)

I've had plenty of KLHs (and others, notably University who also loved them some wire nuts) with dead tweeters and the culprit was green oxidation in, you guessed it, the wire nut connection(s)

Soldered connections, properly dressed after they're done will last a lifetime or two

No excuse not to do the job the best it can be done except laziness or rationalization

Craig

 

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Point well received, My problem in this is that I'm not familiar with soldering aluminum. From what I understand it's not something a person with limited experience soldering such as myself should be doing. Guess I could consider paying someone. Last thing I want to do is mess up a nice pair of 3's .

Thanks to all for the input. Much appreciated.   Ken

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What is it that's aluminum you are soldering?

I assume your original pots are the infamous Aetna-Pollak types?

If so, no aluminum there

Regardless, it's welding aluminum that requires a higher level of skill than ferrous metals

Basic electronics soldering is just that - soldering - heat the joint until it's hot enough to melt the solder and have at it

Keep in mind too that solder, when connecting circuits involving WIRE(s), in and of itself is NOT the connection (we're not taking surface mount here) but rather the insurance that the mechanical connection holds and sustains good contact and conductivity

Always use a good iron,  a eutectic alloy and always use flux (even if the solder wire you use states "rosin core") and you will have few problems if any 

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The only aluminum wires on the 3's are the mids and tweeters where they solder to the terminal block on the baffles.

Everything else is traditional soldering.

When I pull the pots for cleaning, i put them both in a vice and do the soldering where they connect to each other first. Then replace in the cabs, and resolder to the various connections. Make sure you slip on some heat shrink tubing, an inch or so long, onto the wires to be reconnected before making the solder connections so after, you can slide it over the connection, heat the tubing and you're done.

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Thanks For clearing that up. To be honest I was under the impression all the wire was aluminum. I am going to do just that with soldering where they go together first. Thanks For all the help in here! Ken

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21 minutes ago, arken said:

I was under the impression all the wire was aluminum.

The original wire is tinned copper. Good quality and less likely to corrode. The tinning is what makes it look like aluminum.

Kent

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When you have the pots out for cleaning, soak them in a clear distilled vinegar & salt solution for an hour or two. Then rinse off with soap and water.

Now you can clearly inspect the condition of the disks surfaces. If they are in good shape, use the Dremel and a fine grit sanding disk to clean them. Temporarily put them back in and test. If they work properly, or at least you're getting a good signal through the full range, then tale back out, open them up and use some dielectric grease on the disk surface and coils to help prevent future corrosion. Reassemble, solder together reinstall and you're done.

If they are badly corroded, then you'll need to find replacements on fleabay, or replace with 8ohm 15w l-pads from Parts Express. If you go this route, the tabs on the L-pads are in a different sequence than the original pots. There's pics here showing the correct wiring.

Unfortunately I'm out of space to post pics so I cant post the diagram.

Glenn

 

 

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When polishing contacts go to any and all lengths to AVOID harsh abrasives (like sand papers or grinding bits)  Using those will only create micro scratches where new corrosion can more easily return - they also remove more material than is needed to get the contacts clean and shiny (and more importantly- conductive again)

IF you have to use an abrasive (mechanical) then keep it at 1500 wet/dry paper at most dampened with either deoxit or isopropyl alcohol - insert between the wiper and the coil and work the pot to clean the wiper then flip the paper and just drag it over the coils using only the pressure provided by the tension of the wiper

Use Flitz or Maas applied judiciously with a cotton swab ("Q" tip), work the pot and clean up with 99% alcohol or even deoxit or a product like the CRC stuff for electronics

Clean the brass contacts at either end of the coils with the "Q" tip and the polish as well

Do not wash pots with water or immerse them in anything (liquid) as there is no real need for it

After all the conducting elements are clean then treat them with whatever contact enhancer/preserver you like - I personally use a THIN film of dielectric grease but deoxit is fine here too as well as any number of products designed for the task

The greatest advantage I have found of using dielectric grease is that it will outlast all the others before reapplication is required (if at all) as well as, and more importantly so, reduce contact wear on the wiper.  Makes the pot "feel" better too

Lubricate the shafts with a good heavy grease like one of the Nye lubricant products or similar (a thin film of the 300,000 cSt silicone so popular for fixing turntable cue lifts works well too) to give your controls that nice smooth tactile feel as well as sealing them from the elements - whatever you have on hand or is practical for you, just don't reassemble the pots "dry" through the bushing

The trick to getting 100% results to restoring these things is to go EASY on them when cleaning

Craig

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As for soldering aluminum?  If Kester SP-44 (now discontinued and hard to find - luckily I bought a whole pound off the auction site a while back from an electronics store closeout) won't do the trick, you'll have to use one of the highly activated/aggressive types like F61A or similar - plenty of choices available on-line and in small quantity

I've never had any issues with the little bit of aluminum work I've encountered BUT you have to really clean he aluminum to get it to stick no matter what flux you use - as in lightly sand the joint and clean it - don't fool around and do the work right away

The rest is the same as soldering any wire - just buy yourself a small bottle of aluminum flux and keep it on hand for the rare occasions you might need it

ALWAYS use flux for ANY soldering job and ALWAYS use a eutectic blend and you shouldn't have any problems

Craig

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On 6/8/2018 at 12:43 PM, arken said:

There is a Kester 44 rosin core solder 60/40 .031 .05 oz.  on eBay for 4.25 Sound like it? Thanks Ken

"44" is Kester's product line

60/40 is perfectly fine but it is NOT a eutectic alloy 

Eutectic solder melts at a slightly lower temperature and solidifies (goes from liquid to solid) almost instantly so less chance of grey, grainy or cold joints - also gives you better wetting

This characteristic is also of great help when you are dealing with delicate or hard to hold/get to joints

If you are preparing to purchase some solder get Kester 63/37 - Parts Express or any of the big vendors will have it 

It will cost you 2 or 3 dollars more than the 60/40 but it is well worth the nominal increase

The Kester # is  24-6337-0027

And yes, I think the .031" wire is the most versatile size wire

The number I gave you is for a pound - I quite buying the small tubes a long time ago - the costs for those will eat you alive over time, especially if you do even a moderate amount of work

The 1/2 ounce tubes should cost around 3 bucks, so no, that's not such a great deal UNLESS that price includes shipping

If that's all you want or need, buy it from Parts Express when you order your caps so the shipping won't eat you alive - they have 63/37 in the small 1/2 ounce tubes as well (I gave my opinion on what caps I would use in your other thread)  If you elect to go with my advice then you'll be able get all of your parts and supplies from the same vendor - i.e. one order - one shipping cost

https://www.parts-express.com/kester-pocket-pak-solder-63-37-0031-050-oz-tube--370-053

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8 hours ago, Analogman said:

Do not wash pots with water or immerse them in anything (liquid) as there is no real need for it

I figured this out a couple of years ago after cleaning up a dozen or so of those Aetna-Pollak pots. I use a fiberglass polishing pen to clean the up now days. 

http://www.cooltools.us/Scratch-Brush-Pen-Style-Fiberglass-p/brn-207.htm

The secret to a successful restoration is having examples that are not totally corroded.  I wish AR would have used higher quality potentometers, but it is what it is. That is why they eventually went to switches and resisters.   

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9 hours ago, Analogman said:

Do not wash pots with water or immerse them in anything (liquid) as there is no real need for it

As we are seeing from many experienced hands in this thread, there is more than one way to skin a cat. One just needs to know what they are trying to accomplish - - - several different roads can lead to the same destination. 

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2 hours ago, larrybody said:

I figured this out a couple of years ago after cleaning up a dozen or so of those Aetna-Pollak pots. I use a fiberglass polishing pen to clean the up now days. 

http://www.cooltools.us/Scratch-Brush-Pen-Style-Fiberglass-p/brn-207.htm

The secret to a successful restoration is having examples that are not totally corroded.  I wish AR would have used higher quality potentometers, but it is what it is. That is why they eventually went to switches and resisters.   

I think the Aetna-Pollak pots are of very high quality, especially for a vented wire wound type - they're just one of those parts that's never, if ever, serviced by typical consumer type end users

Out of sight out of mind and for 99.9% of the typical AR owners back in the day and were given little thought if any until they misbehaved, generally decades after the speakers were new

It's amazing how long so many of them have lasted with zero service - same as with JBL and a few other who used similar types

Those same pots in a studio or pro environment would be on a list of things receiving regular and routine maintenance

It's not the pots' fault

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On 6/8/2018 at 7:20 PM, ra.ra said:

As we are seeing from many experienced hands in this thread, there is more than one way to skin a cat. One just needs to know what they are trying to accomplish - - - several different roads can lead to the same destination. 

I would think the whole what's trying to be accomplished thing is pretty much the same for all of us - to restore the pots to "as new" working order or as close to it as is possible

Many ways will work that's for sure but no need for a sledge hammer when a scalpel will do - and do less damage/shorten the life of the pot in the meantime as well

I personally see no merit or upside to washing anything (with water) I'm going to take apart anyway - especially anything electronics related

If there is so much corrosion on the wiper (the green rot) that I need to give it an acid bath first to determine the condition of what I'm working with (if it's still serviceable) then I can pretty much make the call right then and there I need another candidate

That's the road I like to take

Craig

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All right I ordered my Kester 44 63/37 eutectic solder and aluminum flux along with my capacitors! I'll use the polys on another job or send back. I really want the 3's to sound like they were intended to sound. I'm a little nervous but I'll be ok. This will be my 3rd time, set of 11a's and a set of 3a's. When I started with Acoustic Research a while back I just knew I liked the sound and the look, I had no idea that I would enjoy the whole process of working on them. The 3's I purchased were from a fellow in Canada. Unbelievable physical condition but none of the tweeters or midranges worked and one of the woofers makes a popping sound. So I tested them (mids+tweeters) with an old low power receiver and they all work! I am sending the woofer to Larry at Vintage-AR who did a terrific job with the woofers in the 11's. I very much appreciate all the great advise I get from you guys. I am not really a mechanically gifted person but I can follow instructions. Thanks a bunch Ken :D

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15 hours ago, arken said:

All right I ordered my Kester 44 63/37 eutectic solder and aluminum flux along with my capacitors! I'll use the polys on another job or send back. I really want the 3's to sound like they were intended to sound. I'm a little nervous but I'll be ok. This will be my 3rd time, set of 11a's and a set of 3a's. When I started with Acoustic Research a while back I just knew I liked the sound and the look, I had no idea that I would enjoy the whole process of working on them. The 3's I purchased were from a fellow in Canada. Unbelievable physical condition but none of the tweeters or midranges worked and one of the woofers makes a popping sound. So I tested them (mids+tweeters) with an old low power receiver and they all work! I am sending the woofer to Larry at Vintage-AR who did a terrific job with the woofers in the 11's. I very much appreciate all the great advise I get from you guys. I am not really a mechanically gifted person but I can follow instructions. Thanks a bunch Ken :D

Great!  Sounds good, you'll be fine

As for the flux, you don't need flux for aluminum work unless you are soldering aluminum

Like I posted earlier up this thread, SP-44 or similar is fine for everything else

Not a big deal no matter though

Craig

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On 6/9/2018 at 8:45 AM, arken said:

All right I ordered my Kester 44 63/37 eutectic solder and aluminum flux along with my capacitors! I'll use the polys on another job or send back. I really want the 3's to sound like they were intended to sound. I'm a little nervous but I'll be ok. This will be my 3rd time, set of 11a's and a set of 3a's. When I started with Acoustic Research a while back I just knew I liked the sound and the look, I had no idea that I would enjoy the whole process of working on them. The 3's I purchased were from a fellow in Canada. Unbelievable physical condition but none of the tweeters or midranges worked and one of the woofers makes a popping sound. So I tested them (mids+tweeters) with an old low power receiver and they all work! I am sending the woofer to Larry at Vintage-AR who did a terrific job with the woofers in the 11's. I very much appreciate all the great advise I get from you guys. I am not really a mechanically gifted person but I can follow instructions. Thanks a bunch Ken :D

Ken,

I do most of the driver repairs for Larry/Vintage AR. Glad to hear the AR-11 woofers are working out satisfactorily. Depending on a number of typical issues, your AR-3 woofer will likely be a more difficult repair.

Some additional thoughts regarding the repairs and recommendations discussed above:

-Given the design of the AR-3 (variable level controls) and the typical variances in ancient drivers. I see no reason to return your poly caps. Early speakers will respond well to any type of capacitor. In fact, the earliest AR-3's had oil-filled type electrolytic capacitors (which seldom need to be replaced), and don't behave exactly like the later AR caps. Imo, this is the least of your concerns during your restoration adventure.

-Only AR-3 mid and tweeter voice coil leads soldered to the front terminals on the cabinet are aluminum. When working on AR-3 mids and tweeters I change these leads to tinned copper using a dedicated solder and flux. Though Kester is the best for anything else, it will not work well for this purpose.

-Your AR-3 mids may need attention. They often suffer from stiffened suspensions these days, resulting in less than optimal output. (Btw, this typical issue will greatly supersede any capacitor type concerns.)

-The crossover wire inside the cabinet is tinned copper. If you are not crazy about soldering lots of connections in the cabinet, wire nuts will work just fine when you are using the original type tinned crossover wire. Like Craig, I'm not a fan of using the nuts on bare copper where oxidation and corrosion is more likely to become an issue over time. I have seldom seen a corrosion issue, however, with tinned ("marine") copper crossover wire...and you will never hear the difference.

-Aetna-Pollak pots are mechanically well built, but they are often cursed with caked, green corrosion. There is often no way to gently clean the disk and wipers. They need to be disassembled, sanded and/or dremel-ed with a wire brush...and when you get through the corrosion you will often find pits under it, and/or tiny holes in the wiper tips. When this is the case, I toss them and find better originals, or, more likely, install L-pads. Due to the construction and placement of these pots, no exterior routine maintenance is possible to deal with corrosion, and the speakers have to be opened to service them. Be aware, however, that the coil of resistance wire in the pot will not be corroded and should be treated gently. Rough treatment can change its value and/or make it lose contact with the end terminals. Btw,  I agree with not soaking the controls in anything.

I have been repairing speakers for a long time, and AP pots found in early Cerwin Vega and Infinity speakers all suffer from the same type of corrosion issues. Later iterations of AP controls have different metal on the contact surfaces (nickel?), and usually exhibit an easy-to-remove tarnish. AP pots are fairly unique regarding the aggressive corrosion so often found in them. The first time I saw it was in an 11 year old pair of AR-2ax's in 1980!

Roy

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Roy,

I will be sending the woofer this week. I spoke with Larry and he said there is a chance that the cloth won't have to be removed. My plan is to go piece by piece and address each piece as I go. Is there a way I can test the midranges to see if they suffer the stiffened suspension you talked about or would I just need to send to you guys for inspection? I'm in no rush and really want to take the time to do these right. I have the 4 pots leftover from the 3a's (switched to l-pads)and 4 from the 3's I'm hoping to get 4 usable pots from the 8 I have. What do you usually secure the capacitors with ? I used an adhesive with the 3a's but would like to use something else to secure them with for a cleaner look? Look forward to working with you guys again on these.   

Thanks Ken

                                                                                                                   

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5 hours ago, arken said:

Roy,

I will be sending the woofer this week. I spoke with Larry and he said there is a chance that the cloth won't have to be removed. My plan is to go piece by piece and address each piece as I go. Is there a way I can test the midranges to see if they suffer the stiffened suspension you talked about or would I just need to send to you guys for inspection? I'm in no rush and really want to take the time to do these right. I have the 4 pots leftover from the 3a's (switched to l-pads)and 4 from the 3's I'm hoping to get 4 usable pots from the 8 I have. What do you usually secure the capacitors with ? I used an adhesive with the 3a's but would like to use something else to secure them with for a cleaner look? Look forward to working with you guys again on these.   

Thanks Ken                                                                                                               

When you get the speakers up and running you will be able to decide if the mids are functioning satisfactorily. If the mid issue is present it is usually pretty obvious, especially when you compare your completed 3's to your other speakers.

The "Restoring The 3a" document in the CSP Library contains good general AR information regarding level controls and cap installation (page 16, for the caps).

Roy

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