AR2a Repair Recommendations

[dbrown]

I bought a pair of AR2a’s on CL – got them home to find out that the tweeters and mid-ranges do not currently make any sound. From what I have gathered, it is probably an issue with the pots.


I am thinking to do the work on these myself as hiring someone is quite expensive. I also have an interest in doing the work – although also a bit scared to screw something up. FIRST TIMER. These are the posts that I have found thus far.
http://audiokarma.org/forums/index.php?threads/ar2a-help.714333/#post-9608213
http://audiokarma.org/forums/index.php?threads/ar-2a-restoration-pics.696430/

Both of these were super helpful!! @GD70 you are awesome!

Questions:

1. Is there any way that I can clean the pots without going through the trouble of getting the grills off?

2. Opinions on bypassing the pots vs. replacing? I have heard good things about bypassing them, but as a rule I am hesitant to do that sort of modification.

3. Would love to gather a list of tools and parts required before starting. I live in a very small space, and I need to start and finish this project over the course of 1-2 days.

Really appreciate the help! I have learned SO much from this group – thank you in advance!

 

[GD70]

Hey dbrown!
You have a very nice set of speakers!
1. You need to pull the grills, VERY CAREFULLY, they are glued in 6 places, top & bottom corners, and about mid way on the sides, be very careful in the middle as they can bend and break easily, woofers, and the nasty fiberglass filling to access the pots. They will need to be unsoldered and removed, opened up and soaked in a clear distilled vinegar & salt solution for an hour or so, washed and rinsed with soap and water, before you can inspect them for the pot wiper and contact disk condition. A Dremel with a sanding disk is good to have if the disk is pitted as this can smooth it out. While they are open is a good time to replace the caps as well.
2. Plenty of people bypass the pots, but you loose the adjustability feature. Using L-Pads like I did in the restoration keeps this feature.
3. Tools- You will need a soldering iron & solder, flux, screw driver, pliers, wire cutters, work gloves to protect your hands from the fiberglass, a mask, large garbage bags to store the fiberglass in. A putty knife to protect the cabinet edges while gently prying the grills loose. A paint can opener is good for this.

This will not be a 1-2 day project until you have everything at the ready.
Don't be daunted by all this. Be methodical, take your time and take lots of pics for when putting them back together. You'll be well rewarded with great sounding speakers when you're done.

Glenn

 

[Old Guy8]

I've bought Red Devil plastic putty knives, $.59. I use them for grill removal, and scraping, etc. They are gentler on, but can break when prying.

 

[dbrown]

Thanks for the quick responses! I will pick up the putty knives.

I am thinking to get the l-pads in advance. Just in case I cannot clean up the original equipment. Recommend anything for the l pads and the caps? You wrote, "replaced the pots with 15 watt 8ohm L-Pads, and new caps from PE". Is PE a store? Is there a brand you recommmend?

Thanks again.

 

[Old Guy8]

Thanks for the quick responses! I will pick up the putty knives.

I am thinking to get the l-pads in advance. Just in case I cannot clean up the original equipment. Recommend anything for the l pads and the caps? You wrote, "replaced the pots with 15 watt 8ohm L-Pads, and new caps from PE". Is PE a store? Is there a brand you recommmend?

Thanks again.

I can only answer one of your questions. Parts Express is an online store that sells speaker and electronic components and related. Some of thier products use Parts Express as a brand name, also.
Glenn can answer rest.

 

[Drugolf]

Hey Dbrown.
When you order, go ahead and also get some of their driver acoustic sealant tape. AR's require a good seal at all drivers to insure acoustic suspension is working as it should. There is info on the lpads in the AR3a restoration guide over at Classicspeakerpages.net which should help you thru the process as it is mostly similar other than cap values/crossover design etc.

 

[GD70]

Thanks for the quick responses! I will pick up the putty knives.

I am thinking to get the l-pads in advance. Just in case I cannot clean up the original equipment. Recommend anything for the l pads and the caps? You wrote, "replaced the pots with 15 watt 8ohm L-Pads, and new caps from PE". Is PE a store? Is there a brand you recommmend?

Thanks again.

I've been using DAYTON poly caps with good results. PE also carries the L-pads.
Good advice from David.

 

[onplane]

I bought a pair of AR2a’s on CL – got them home to find out that the tweeters and mid-ranges do not currently make any sound. From what I have gathered, it is probably an issue with the pots.


Questions:

1. Is there any way that I can clean the pots without going through the trouble of getting the grills off?

2. Opinions on bypassing the pots vs. replacing? I have heard good things about bypassing them, but as a rule I am hesitant to do that sort of modification.

I am in the minority who believe in the total pot by-pass. AR speakers are simply excellent sound reproduces, but they were designed in a different time with different problems. Thus the major complaint is they sound "laid back", "muffled", "bass heavy", etc.

By-passing the pots will NOT cure all of these ills, but it's going in the right direction. To complete the transition and return voice control to you (once the pots are by-passed), consider bi-amping. That is, one amp to power the woofers and a separate amp for the high frequency drivers. With this scheme you move voice control from corroding pots inside the speakers to volume controls on the amps.

Further, with the right amps you can do this with the factory supplied 3 terminals.

Regards,
Jerry

 

[dbrown]

I am in the minority who believe in the total pot by-pass. AR speakers are simply excellent sound reproduces, but they were designed in a different time with different problems. Thus the major complaint is they sound "laid back", "muffled", "bass heavy", etc.

By-passing the pots will NOT cure all of these ills, but it's going in the right direction. To complete the transition and return voice control to you (once the pots are by-passed), consider bi-amping. That is, one amp to power the woofers and a separate amp for the high frequency drivers. With this scheme you move voice control from corroding pots inside the speakers to volume controls on the amps.

Further, with the right amps you can do this with the factory supplied 3 terminals.

Regards,
Jerry

I definitely did not think of that as an option! Pretty interesting solve. I know very very little about this stuff, but in my mind, it seems like it is a better solution to eliminate resistance where possible - removing the pots should help with that. I also won't have to worry about ever going back in to clean them. At the same time, moving from "original" sort of worries me. And...I am not sure how to go about by-passing them.

 

[onplane]

I definitely did not think of that as an option! Pretty interesting solve. I know very very little about this stuff, but in my mind, it seems like it is a better solution to eliminate resistance where possible - removing the pots should help with that. I also won't have to worry about ever going back in to clean them. At the same time, moving from "original" sort of worries me. And...I am not sure how to go about by-passing them.

To by-pass you'll need a solder iron/gun and follow the attached drawing. I'll attempt to explain each part here.

First off on the mid pot (and this one is the easier), you simply cut the green wire from the mids at the pot. Then re-attach this wire to terminal 1 on the pot where the cap lead is. This takes the pot entirely out of the circuit. (Now leave the pot physically in place otherwise you will have to deal with cabinet leaks.)

Now for the tweeter pot, you once again cut the black wire from the tweeter at the pot AND you cut the cap lead at the pot as well. Now, you twist together the black wire and the cap lead and solder. As long as neither are attached to the pot, it is removed electronically from the circuit.

This completes the process of electronically removing the pots. Naturally they are still in place physically and the grandchildren can play with them to their heart's content, but it will do nothing.

To gain voice control back, however, requires bi-amping. To do with with the factory provided 3 terminals is possible, but tricky. If you need an amp recommendation, let me know, because there is a special unit that's economical and will do everything with a single box.

Regards,
Jerry

 

[dbrown]

THANK YOU for that. Extremely helpful.

 

[dbrown]

Update! I was able to get the grills off without damage. Here was the process I used - hope it is helpful to anyone looking to take this on:

Removed emblems: "a" is just a pin (missing the second one); AR was attached to a screw.

Pulled out the staples quite quickly using the pointed "ice pick like" mini screwdriver that came in my mini screw driver kit and a hammer. I picked a spot between the grill cloth lath, hammered it under the staple, and pried it up a touch. Then I used a nail set to compress the surrounding cloth area. Finally I used a needle-nose pliers to pull them out.

The grill cloth is not only stapled and glued, but reset into the wood - you would think AR's worse nightmare was a loose grill. To break the glue, I used a dental tool (scaler- the one used for putting in fillings- it has a perfect angle and is super strong). This had the right angle for getting between grill fibers and under the particle board. One grill came off a bit harder than the other, but they were both pretty easy actually. Had to use a putty knife on half of the one as the glue was so strong that separated the glill backing vs. releasing at the glue joint.

I also picked up the Dayton caps per @GD70; not sure when they will arrive. I also read about this post: http://likemagicappears.com/projects/av-projects/ar-2ax-speakers/
Good additional source of info, but specific to the ax vs. the a.

 

[Ross6860]

Good job getting the grills off. I broke both of mine but was able to repair them.

I used the L-pads from VintageAR at that auction site. He sells all kinds of AR restoration stuff. He's the only one I've found selling "dope" for the surrounds. It works great BTW and he's a good source.

You woofers should have cloth surrounds that probably will never need replacing.

I could have saved the pots. They can be taken apart and cleaned with deoxit and a brass brush (gently). Actually I gave them to someone on Barter Town that was doing a full restoration and didn't want new parts.

I think you will like them when finished. I have a thread out there showing mine after restoration. They sound great with vintage gear and have plenty of bass IMHO.

 

[camdolla]

Dbrown

I am faced with the very same challenge if I choose to purchase a pair of AR2a’s that have the need for identical repairs.

How did everything turn out?

 

[Justgotohm]

The pots are serviceable, you can remove them taking care to mark what wires you removed from where. They have wire spring clips that pull to the side then the pot will come apart. I removed the internals cleaned them up removing the corrosion, some deoxit, etc. if the plates the contact slides on is pitted you can apply small bits of solder then sand or file down. They have worked very well since. When I recapped I stuck the new caps in the original boxes for the hell of it. I had some pics on here of the pots taken apart but can’t find them. Be sure to mark or align the pots to the plate they mount to so the dials line up on the back of the speaker. Make sure you clean the solder points the spring is attached to inside the pots and the springs as well.

 

[tyella]

The pots are serviceable, you can remove them taking care to mark what wires you removed from where. They have wire spring clips that pull to the side then the pot will come apart. I removed the internals cleaned them up removing the corrosion, some deoxit, etc. if the plates the contact slides on is pitted you can apply small bits of solder then sand or file down. They have worked very well since. When I recapped I stuck the new caps in the original boxes for the hell of it. I had some pics on here of the pots taken apart but can’t find them. Be sure to mark or align the pots to the plate they mount to so the dials line up on the back of the speaker. Make sure you clean the solder points the spring is attached to inside the pots and the springs as well.
View attachment 1248380

Keeping the original boxes is a cool idea!
The salt and vinegar trick really works to clean up those pots. You need to really saturate the vinegar with salt. It takes a LOT. Soak them for a while. After soaking, I used a Dremel tool with a brass brush to remove the caked on crap. Once you get the original pots cleaned up, some white lithium grease will help keep them corrosion-free. Or you can just buy new L-pads.

 

[RxDx]

The center discs can be flipped or replaced for better continuity. I used brass
screws from Lowe's. New discs are sold by bead supply stores.

 

[tyella]

The center discs can be flipped or replaced for better continuity. I used brass
screws from Lowe's. New discs are sold by bead supply stores.

Oh my gawd!!! Why didn't I think of that?! Brilliant!

 

[RxDx]

Thank yew

 

[Ross6860]

Dbrown

I am faced with the very same challenge if I choose to purchase a pair of AR2a’s that have the need for identical repairs.

How did everything turn out?

Unless you really want to try them, or they are really inexpensive, I might recommend a different speaker to mess around with.

Depends on your tastes and what you expect from a speaker. I prefer not quite so "warm" or vintage sounding. This is an old design and the paper mid-range speakers can have issues. The cloth-surround woofers are pretty decent, though.

The AR2ax was the next generation and a bit more modern.

Just my 2 cents.