Beginning an AR 4 resto.

[pmsummer]

Picked up some AR 4 (not x or xa) speakers in decent to good condition. Cabs pretty good (some water damage I can sand down), badges intact, Initial inspection after getting them home reveals the tweeters aren't tweeting. The pots are very stiff, and that may be the problem, but I'm not getting any response from working them back and forth).

I haven't removed the grills yet to do a thorough investigation (they are glued on VERY well, and I don't want to break 'em). Maybe this weekend.

But assuming worse-case scenario and the tweets have flown the coop... I've got some Dayton 1 1/8th silk dome tweets I can use. Any ideas on XO mods?

Thanks in advance!

[dynaco_dan]

Picked up some AR 4 (not x or xa) speakers in decent to good condition. Cabs pretty good (some water damage I can sand down), badges intact, Initial inspection after getting them home reveals the tweeters aren't tweeting. The pots are very stiff, and that may be the problem, but I'm not getting any response from working them back and forth).

I haven't removed the grills yet to do a thorough investigation (they are glued on VERY well, and I don't want to break 'em). Maybe this weekend.

But assuming worse-case scenario and the tweets have flown the coop... I've got some Dayton 1 1/8th silk dome tweets I can use. Any ideas on XO mods?

Thanks in advance!

Hi there;

The pots require removing and given a complete tune-up.

Replacement tweeters can be bought for about $10.00 each off ebay but with the pot cleaning you probably will have the tweeters working again.

AR-2AX mids, AR-1X's first tweeter, and AR-2X's first tweeter are the same drivers.

[pmsummer]

AR-2AX mids, AR-1X's first tweeter, and AR-2X's first tweeter are the same drivers.

Thanks, Dan. That helps, should it indeed be worse-case!

[dynaco_dan]

Thanks, Dan. That helps, should it indeed be worse-case!

Hi again;

Removing the grille cloths is a small challenge in itself.

To minimize cabinet damage and salvage the frames and cloth's, read postings that may touch upon several techniques used.

Accessing the pots is a prickly business, care and patience pay's off big time.

Do not intermix the pot parts, I remember you have at least two different pot shafts.

There has been lot's of opened up pot's photos posted to give you a bird's eye view.

Cleaning up the pots with due care, will mean not having to dig back into those enclosures for many, many years.

There is at least one new pot manufactured of similar but different construction still available that is physically interchangeable with the existing Aetna-Pollock pot version.

It is Chinese made and built like a proverbial tank, with the rear coil/rotor open instead the the OEM closed back version.

If you should decide to go this route, a bridge of a plastic 1 1/2" or 2" - 2 hole pipe clamp, the actual size has not been determined yet, epoxied over the rear of the pot, will keep insulation and wire clear and it still can be removed in a pinch.

After spending a lot of effort to come up with something suitable as a heat shield, I finally decided this was the cheapest, non-conductive electrically, readily available, and within the means of any hobbiest to apply or remove, providing it is not touching the actual pot's rear.

I have a huge surplus of assorted Chinese tea cups, which I experimented with, for sale. LOL LOL

[pmsummer]

Thanks for the insight. Yeah, I've rebuilt 3a and 2ax ARs, so the pots and I are old friends.

I was able to get all 20 staples out without damaging the grills. The cloth is discolored, but not too badly considering their age. When I opened them up, I saw fiberglass and not rockwool (which is usually the case when the grills aren't horribly discolored... in my experience). I didn't dig into them today because I can't find my box of surgical gloves and masks.

Hi again;

Removing the grille cloths is a small challenge in itself.

To minimize cabinet damage and salvage the frames and cloth's, read postings that may touch upon several techniques used.

Accessing the pots is a prickly business, care and patience pay's off big time.

Do not intermix the pot parts, I remember you have at least two different pot shafts.

There has been lot's of opened up pot's photos posted to give you a bird's eye view.

Cleaning up the pots with due care, will mean not having to dig back into those enclosures for many, many years.

There is at least one new pot manufactured of similar but different construction still available that is physically interchangeable with the existing Aetna-Pollock pot version.

It is Chinese made and built like a proverbial tank, with the rear coil/rotor open instead the the OEM closed back version.

If you should decide to go this route, a bridge of a plastic 1 1/2" or 2" - 2 hole pipe clamp, the actual size has not been determined yet, epoxied over the rear of the pot, will keep insulation and wire clear and it still can be removed in a pinch.

After spending a lot of effort to come up with something suitable as a heat shield, I finally decided this was the cheapest, non-conductive electrically, readily available, and within the means of any hobbiest to apply or remove, providing it is not touching the actual pot's rear.

I have a huge surplus of assorted Chinese tea cups, which I experimented with, for sale. LOL LOL

[Analogman]

Do not intermix the pot parts, I remember you have at least two different pot shafts.

Oops! I never knew that was the case. On the most recent set I restored I mixed it all up!

I've never seen a pair of "AR" with two different pots in one cab. Is this difference obvious?

Beyond the red plastic "arrowed" version and the one with the adjustable (set screw) knob?

Please advise.

Regards,

Craig

[JKent]

Just my 2 cents: I do not think there would be 2 different pots in 1 cab, and the 4 only had 1 per cab anyway. But there were different pots--red plastic shaft, black plastic shaft and aluminum shaft. There could be different pots in the 2 spkrs. Btw--on my 1st 2ax restoration I did use 2 different pots per cabinet. Thought is was cool. Maybe not.

Anyway--you can certainly clean and restore the pots, and that is the authentic way to go, but some AR restoration experts with far more experience than I advocate the use of L-pads. They are inexpensive, readily available, durable, and sound fine in the AR 4 (some debate about their use in the 3a).

You can get L-pads with very good directions for replacing the pots at Vintage AR. Or if you know what you are doing, order a pair from Madisound or Parts Express.

Be SURE to read the EXCELLENT AR3a restoration booklet pinned to the top of this section. It was put together by some of the best AR experts and much of the info in there is relevant to restorations in general, and to your AR4s.

Finally, despite how good your 40-year-old grille cloth may look, the Irish Linen referenced in the AR3a booklet will make your speakers look beautiful!

Good luck

Kent