When does it stop being classic?

[bobby_sunshine]

I bought my AR 2ax in 1973 and have just finished rennovating them with the help of all the fabulous resources here. A collective thank you.

They were in rough shape, even though always used or stored in a heated climate contorlled area. The cabinets were great but one of the woofers was bad (more than refoaming, mangled voice coil and broken spider (replace with ones from AB Tech) and both tweeters were dead (replaced with HiVi Q1R). I could find some good spots on the pots after cleaning, but they still aren't great. And, of course, they needed recapping.

So what's left is the box, the midrange drivers, the crossover inductor, some hookup wire and the terminals. Even though I've been sucked in with fixing one problem after the next, I am happy with the result. I like them a lot better than most of the things I've listened to lately, at least the things that are affordable.

1. What are good replacements for the 2ax midrange drivers?

2. I see a lot about people using L-pads to replace the pots. Is there a reason I see almost nothing about using AB Techs potentiometers? They are not ceramic but seem reasonably priced (around $13) and I think are closed backed and within an ohm or two of the originals.

3. At this point what I have isn't much of the original, though it sounds reasonably close. Do people build 2ax or 3a from scratch? The biggest hurdle seems to be the cabinet. It's mostly MDF with, in my case, a walnut veneer. I have reasonable woodworking skills and the equipment, and some spalted sycamore from a tree that blew down in my yard. So for about $400 for the 2ax or $550 for a pair of 3a knockoff plus a Saturday in the woodshop and I would have those rear speakers for my surround sound.

A lot of the speaker building venture seems allocated to electronic/acoustic arts with matching components, designing crossovers, cabinet volumes and baffles. But since I know the sound I like (or at leas A sound I like) it is simply a matter of making it so: credit card, table saw, screwdriver and glue. While the resources here are aimed at repairing AR speakers, they seem just as well suited to recreating them.

4. Am I missing something? Is this something people do?

Thanks for any comments and thanks again for giving me back my 2ax.

Bob

[Carlspeak]

I worked on some AR2ax's awhile back that had a phenolic ring tweeter driver in place of the angled pair of mids used in early 2a's and that was a kit sold by an AR authorized repair shop back in the day. Here's a link to that thread http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6705&hl=ar2ax

As far as recreating a pair of 3a's, you could come close by building a similar sized and shaped cabinet with the same bracing. The key to your success would be getting a pair of 3a woofers, not knock-off's like those sold by ABtechservices, but a genuine pair that were canabilized. They could either be the later ceramic magnet/foam surround type or, the more rare alnico magnet, cloth surround types. As far as the mid and tweeter are concerned, you'd might find vintage ones of those as well on the bay or elsewhere and take a chance on getting poor performing tweeters. Or, my Super-mod kit does the originals one better with modern, high-quality Seas drivers and a custom crossover.

[RoyC]

2. I see a lot about people using L-pads to replace the pots. Is there a reason I see almost nothing about using AB Techs potentiometers? They are not ceramic but seem reasonably priced (around $13) and I think are closed backed and within an ohm or two of the originals.

Thanks for any comments and thanks again for giving me back my 2ax.

Bob

Hi Bob,

The AB Tech "potentiometer" is simply a modern 8 ohm L-pad. The website is misleading. ABT has not sold replacements with the same electrical characteristics as the original pots for a VERY long time. The same (15 watt, 8 ohm) L-pad can be purchased from Madisound, Parts Express, Erse, and Meniscus for $4 to $6.

The AB Tech 10 inch woofer and HiVi tweeter you are using are not bad replacements when used individually, but they, like most modern drivers, are not the same as the originals. Even if the woodworking can be accompiished, recreating the old AR models from scratch is not an easy task due to the scarcity of appropriate drivers and the skills required to do so. A person with a speaker building background, and lots of experience, will more likely try to design a new system "based" on an original (as Carl has done above). Even then, though the results may be very good, the system will most likely not sound like the original.

Roy

[JKent]

Bob,

Regarding the replacement tweeter (mid) Carl wrote about, he had this to say: "I believe the PE 8 ohm phenolic ring tweeter should work out fine and not require an adapter plate.
A 13 uF cap and parallel 0.3 mH coil should tame that 1100 hz hump."

But why replace the originals? Are they shot? If they are good by all means use them! Your original question is valid. If after all the repairs the only thing original is the cabinet, they're not really classic speakers. Of course, they may still be very good speakers.

Reminds me of the guy who'd had the same hammer for 50 years. The handle had been replaced 4 times and the head twice

Kent

[Carlspeak]

Bob,

Regarding the replacement tweeter (mid) Carl wrote about, he had this to say: "I believe the PE 8 ohm phenolic ring tweeter should work out fine and not require an adapter plate.

A 13 uF cap and parallel 0.3 mH coil should tame that 1100 hz hump."

But why replace the originals? Are they shot? If they are good by all means use them! Your original question is valid. If after all the repairs the only thing original is the cabinet, they're not really classic speakers. Of course, they may still be very good speakers.

Reminds me of the guy who'd had the same hammer for 50 years. The handle had been replaced 4 times and the head twice

Kent

That quote of mine you referenced was in regards to the PRT used as a tweeter. The link I provided was for the same driver used as a mid which is what, I believe, the OP is looking for. What I can't recall at the moment is what the xo was like for that PRT/mid application.

[JKent]

Carl

Maybe I'm confused. My understanding is that the 2ax doesn't really have a mid and tweeter but rather a tweeter and a super-tweeter. As I understood your post, the PRT tweeter could be used to replace the 2ax mid/tweet. Let's call it the mid to avoid confusion, since it is the middle of the three drivers. So just to clarify: Are you saying that when using the PRT as a "mid" you do NOT add the 13uF cap and 0.3mH coil? Just use it as is?

And as I wrote before: Use the originals if they are not blown.

Kent