AR3a repair

[dxho]

I just got a pair (4 digit serials, cloth surrounds) knowing one of the tweeters was non-original. But it got complicated; I dropped one, and it shifted the magnet in the woofer. That bound the voice coil, rendering it inoperable (the coil shows about 2.4 ohms of 'resistance'). However, these things can be completely disassembled w/o damage, which is what I've done. I think I've got the voice coil slug centered. I'm just wondering the best glue to use- both the spider and surround rings pulled off with no effort.

[dxho]

Woofer repaired: pots cleaned; seals tightened. Even with the original caps, these things sound very nice. I'll be a/b/c-ing them with 2AXs and KLH Model Fours shortly. Serial numbers 3A-04815 and 3A-04822. Cabinets are so-so. The sides are starting to separate slightly at their meeting edges. If these ever left the garage, I might consider new veneer.

[dxho]

Fabulous. Quite pleased with the sound, inconsistent as it is. The pots keep dropping out, so I'm going to replace them. Unless there's some sort of chemical... There's not much corrosion, and it's cost little material.

And I'm in the market for an original tweeter. New caps and new stuffing soon. That should do it.

Even in unrestored condition, these really are noticeable in their ability to hit the very bottom notes, from about 35 or 40 hz on down. They do this better than the KLH Model Four, the closest equivalent 'classic' speaker I've found mentioned on CSP. The Four is a little brighter (perhaps a little 'bright'), as also mentioned, but this is easily adjustable with an EQ. Comparing these two at a flat tonal setting, the 3a doesn't lose anything in presence or detail.

[dualref]

If you have the original ceramic pots in your 3a's then you can clean them. There is a clip that pops off and you can then get into the inside of them. A Dremel tool used very carefully will clean them up nicely.

You can glue the veneer down where it is trying to separate.

The -3a's are my favorite speaker system. I am currently working on mine right now. I'm going to recap the crossovers just to get the speakers back in the original spec. I haven't yet measured the drift on the old capacitors yet, but I am going to see how far they have drifted before replacing them.

My speakers are low serial numbers as well. Built in April or May of 68'.

[dxho]

I used the little wire wheel with the Dremel (because I'm dangerous with anything more abrasive on a power tool), and that wasn't cutting the corrosion. So I scraped it off and then used, oh I don't know, 1000 grit sandpaper to even the surface up a bit (the center disc on the ceramic side for the inside arm of the wiper). I also hit the wiper arms with a little abrasion and scraping. I didn't do anything to the coils, as they looked clean. Maybe that's the problem? They're all solid otherwise (except for one wiper arm that's getting a little weak).

I wasn't clear; the separation is from the particle board starting to swell. These were in a damp place a little too long. But I'm thinking if I was serious that the veneer could be stripped, the wood could be planed back to size, and then the whole thing re-veneered. That's down the road. I just want to restore them electrically at the moment.

Don't know why I waited so long to get a 3-series pair. I've loved the 2s for 20 years.

[dualref]

Ooohhh, moisture is not good for speaker systems. The particle board you are speaking of is this the one the pots and cross overs are mounted on? If so, that could be replaced pretty easily. What I would do is take to woofers out and place the speakers in a dry area and let them dehumidify for about a week. If you have a dehumidifier for the room, I would use that too. And maybe even point a fan at low speed inside the speaker housings. I would definitely lay them on their backs while doing this.

Look on the speakers for any rust. If there is any I would lightly sand it off.

And be careful with the veneer. I have never heard of anyone planing it, just sanding it is usually all that's needed and then restain with some Watco Walnut stain. It comes in a few varieties of color so you have a choice. I don't think the veneer would take kindly to planing.

[dxho]

The swelling is in the cabinet wood itself. It's not a lot, but can be seen. The tops have a gap in the veneer where they meet the side panels. Damage seems confined to the outside. Drivers looked okay inside.

I was talking about taking the veneer off completely, planing the underlying wood back to square (or some approximation), then applying new veneer. Another project 'on the list' :-)

[dualref]

Oh, I see what you are saying now.

What I would do is dry them out the best you can as I described and see what the veneer does. Sometimes when wet wood dries, it can return to it's original shape if you are lucky.

You are going to want to have these speakers are dry as possible when you fill them with fiberglass at the end of the restoration. When fiberglass gets wet it really stinks! Literally!

[dxho]

I think they're pretty much dry and that this is the state of the cabs. This is old damage, not recent, and pretty much confined to the outside. I don't think they ever got wet or damp inside.