Heathkit AS-2B

[Rhubarb]

Hello all.

I just thought I'd share these pictures with you all...I picked these up yesterday for $45. I've read that they are just AR-2's in kit form.

[JKent]

Nice! Yes, they are AR 2s. Scary grille cloth!

Those are the cool cast aluminum frame AR woofers.

The manual is a nice plus!

Happy listening.

Kent

[Steve F]

Interesting that Heathkit spec's the crossover at '1000 cps' when AR spec'd it as 2000.

Looking at the x-o schematic, just the woof section, a first-order on the woofer with a 1.1mH choke does work out to around 1000 Hz, but the HP on the tweets is much higher than that, so AR just said "2000 Hz," which is close enough.

People not closely involved with x-o design--the normal, casual enthusiast-- think that x-o's are absolute and that drivers hit "on-off brick walls" in the crossover.

A friend of mine sent me a link to a Klipsch floorstander that he was considering buying at a great deal. The Klipsch website spec'd the crossover as "2633Hz." Very amusing.

Steve F.

[JKent]

Interesting that Heathkit spec's the crossover at '1000 cps' when AR spec'd it as 2000.

Looking at the x-o schematic, just the woof section, a first-order on the woofer with a 1.1mH choke does work out to around 1000 Hz, but the HP on the tweets is much higher than that, so AR just said "2000 Hz," which is close enough.

People not closely involved with x-o design--the normal, casual enthusiast-- think that x-o's are absolute and that drivers hit "on-off brick walls" in the crossover.

A friend of mine sent me a link to a Klipsch floorstander that he was considering buying at a great deal. The Klipsch website spec'd the crossover as "2633Hz." Very amusing.

Steve F.

At one time I had an empty pair of AS2 cabinets, with xo. The XO was apparently a Heathkit product--not the one found in the AR2. I don't have a schematic for the AR2 xo so I don't know if the values of the components were the same..

Kent

[Zilch]

In most AR crossovers I've studied, the filters primarily do "response shaping," with the natural rolloff of the drivers providing the basic crossover.

AR2 is an exception; the dual crossfired mids functioning as tweeters have WAY wider native bandwidth....

[Rhubarb]

I plan on replacing the caps. I'll take some innards photos when I get there.

Is there anything else I should consider while I'm in there. Changing values, cleaning and/or replacing the l-pads, etc?

[JKent]

I plan on replacing the caps. I'll take some innards photos when I get there.

Is there anything else I should consider while I'm in there. Changing values, cleaning and/or replacing the l-pads, etc?

I "think" those may be L-Pads and not pots (like AR used). If so, they may be fine. You could check them with an ohmmeter or just buy replacements from PE or Mad. Here is a photo of the original. If PeteB is following this he may be able to tell you more about it.

BTW--looks like you have the "marine grade plywood" cabinet--nice! Is it the Mahogany veneer? If so, I would recommend Howard's Restor-a-Finish in Mahogany to bring them back to life without sanding. Vern may want to contribute to this discussion--I think he has a number of photos of Heathkits.

Do a search here on "Heathkit" for more discussion of these speakers.

When you pull the woofer, try to save the Kempac (flimsy porous paper) behind it, but it will probably just crumble. If that is the case you will have to find a replacement (search forum on Kempac). Basically you just need a piece of acoustically transparent cloth that will keep the fiberglass fibers out of the woofer. You will also have to reseal the woofer when you put it back in. PE sells a suitable soft gasket material (36" Speaker Sealing Caulk) or you can use Mortite window putty, or "duct sealant" sold in the electrical dept of hardware stores (and Lowes Depot).

Choice of caps is up to you. Daytons from PE are fine. The 6.2uF value is close enough to 6uF (+/- 10% is fine).

Kent

[RoyC]

I plan on replacing the caps. I'll take some innards photos when I get there.

Is there anything else I should consider while I'm in there. Changing values, cleaning and/or replacing the l-pads, etc?

AR never used "l-pads" as level controls in those old speakers. Sometimes a pot, of which only the series resistance leg was utilized, provided simple variable series resistance to the high range drivers. Whatever, it is most likely a 15 ohm pot.

It should be tested and cleaned, and is easily replaced, if necessary.

Roy

[genek]

I "think" those may be L-Pads and not pots (like AR used).

The schematic diagram in the manual indicates it is a rheostat/pot, not an L-pad, though the one in your photos certainly does not appear to be the same A-P unit as the AR-branded models.

[JKent]

The schematic diagram in the manual indicates it is a rheostat/pot, not an L-pad

OOps!

And I see they are AS-2B, indicating "blond" and not mahogany. So go with the Howard's in Neutral and you should be fine

Kent

[Pete B]

Hi Kent, and all, I'd say yes those are simple pots and not L-pads.

[Rhubarb]

Well Shucks!

I suppose I am an irresponsible speaker owner, but I was testing these AS-2 speakers on my Sherwood S-8900A underneath my KLH 5s. They sounded great stacked with the fives. The highs of the fives combined with the bass of the AS-2s seemed to be making that synergy that I've heard so much about.

Anyway, I was using them without the grills on, and my cat had the need to investigate the woofer. Investigate, she did, with abandon....

It's been a couple weeks, and now I don't feel quite so disgusted with myself, I am looking to R&R these puppies.

I see that Vintage AR has a replacement woofer. $100 seems a bit steep to me, is there anywhere else to source this driver?

Here are few shots of the driver.

I got the PE Dayton caps that Kent Suggested.

Here are a few shots of the original x-over.

Here is the Kempac It's in great condition. Kinda looks and feels like crepe paper. The damping material seems denser and more crumbly than normal fiberglass "insulation".

Finally, I have to do something about the veneer on one of the speakers...it's bubbling and splitting. I would love to save it, but it looks pretty shabby as is. I have been pricing veneer, but a complete re-veneer seems a bit out of my realm.

Hopefully this post isn't TOO image laden. To anyone with dial-up, I apologize in advance.

[JKent]

So now you have a couple of issues. Regarding the woofer--that is an original aluminum frame job that was used in the 2, 2a and EARLY 2ax. You may be able to find one on ebay. OR send it to Bill LeGall at Millersound for repair (reconing). You might also try patching it with Alene's Tacky glue and some thin paper. The stuff sold as lens wipes might work--it is light, thin and very tough.

Lowes and Home Depot sell iron-on real oak veneer. It's not that difficult to apply. The first step would be to get the old bubbled stuff off or at least cut out the bubbles, fill and sand to get a perfectly smooth surface. Those cabs look like the marine plywood and may be worth salvaging.

OTOH, maybe just cut your losses. You can probably sell the good woofer for a good price and the damaged one for something to at least recoup the $45. The original paperwork is worth something, and you "may" even be able to sell the empty cabinets on Craigslist (no shipping). I doubt the tweets would fetch much but you never know.

Then start all over. You can find some more nice vintage speakers at a bargain price, and this time keep kitty away from the woofers

Good luck

Kent