AR2a woes, seeking advice

[fiddlefye]

I am new to this forum having been directed here by my friends over at AK. Seems like a great place you have here! Given I have a few sets of "classic" speakers I should have landed here long ago.

Last Summer I picked up a seemingly mint pair or AR2a's (with the stands no less) at a church rummage sale for the princely sum of $5. When I got them home I noticed that the tweeters weren't working, pretty typical stuff apparently. They finally got dismantled this week and it turns out there is another issue beside the bad pot wipers. The cones of the mid drivers have become brittle and basically are disintegrating. What to do?

I had read that at one time there was a kit from AR to upgrade the mids in the 2a to 2ax standard. Obviously such is no longer available, but is there any way in this age to go about doing the same thing? Would this be the best way to go about things or does anyone have a good alternative suggestion that would maintain the essential character of the speakers?

I'd love to get them in good shape and put them to use soon. Advice (of the concrete sort especially) would be deeply appreciated.

[Carlspeak]

Here's an option for you to consider.

At one point in time as AR was transitioning the AR2a's from the two angled radio speaker midrange configuration to the single cone midrange, they offered a kit that consisted of a MDF board and phenolic ring tweeter (PRT). The link below shows a picture I took of an AR2a I worked on that has this install. The MDF board was pre-drilled and sized to fit into the cavity left by the plastic cavity used by the old radio midrange drivers.

Strangly enough, the PRT served as a midrange for this 'upgrade'. No crossover change was needed. Parts express still sells those PRT's (8 ohms) for a reasonable price. All you need do is fabricate the MDF board and you should be able to match what AR did.

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6705&hl=ar2ax

[fiddlefye]

Here's an option for you to consider.

At one point in time as AR was transitioning the AR2a's from the two angled radio speaker midrange configuration to the single cone midrange, they offered a kit that consisted of a MDF board and phenolic ring tweeter (PRT). The link below shows a picture I took of an AR2a I worked on that has this install. The MDF board was pre-drilled and sized to fit into the cavity left by the plastic cavity used by the old radio midrange drivers.

Strangly enough, the PRT served as a midrange for this 'upgrade'. No crossover change was needed. Parts express still sells those PRT's (8 ohms) for a reasonable price. All you need do is fabricate the MDF board and you should be able to match what AR did.

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6705&hl=ar2ax

That is a really interesting idea. I'd love to hear how it turned out, but suspect I'd just have to take it on faith. I will have to get the tweeters tested to see if they are still working and if so it looks like a good project. The woofers are both perfect and the cabs are just about mint so it would be a worthwhile project. Has anyone heard such a conversion?

[Carlspeak]

I heard the conversion and measured it as you can see at the link I provided. 'nuff said. It sounded good. My only concern now would be whether or not the current PE PRT 1200 hz hump would be a problem.

[fiddlefye]

I heard the conversion and measured it as you can see at the link I provided. 'nuff said. It sounded good. My only concern now would be whether or not the current PE PRT 1200 hz hump would be a problem.

This is looking more and more like a good path to follow. I'll have to see what the costs are for the PE parts, but considering what I have in the speakers so far I suspect it would even be economically feasible to go this route. Thanks for the advice!

[ra.ra]

Just another thought here. Carl seems to have been able to achieve excellent performance from his client's speakers with the PRT tweeter, but I think it was determined that that particular tweeter was never an original AR component. The first pic attached shows the 3-1/2" mid-range (with damping and mesh) in the wood panel which was used to convert an AR-2 to an AR-2x, or an AR-2a to an AR-2ax, I believe. I am not entirely sure if/what crossover modifications may have been required to accommodate the driver change. These mid-range drivers are not that difficult to come by, and if you wish to restore your speakers to fully original, the two angled mid drivers are also available not infrequently (see attachment 2).

[soundminded]

I've had a pair of AR2as in my basement for many years waiting for me to do something with them. All four original Jensen? midrange drivers have warped cones. I saw a pair at Millersound 4 years ago when I had my AR9s refoamed. Those midrange drivers were in the same condition. Bill was "manufacturing" new cones for them because the owner wanted an authentic restoration. I don't think his opinion of those drivers was any better than mine is. They seemed like ordinary table radio speakers to me. I restored a pair of AR2axs which needed one new midrange driver. I bought 3 on e-bay. They were cheap. I've been thinking of converting the AR2a to an early version AR2ax with them. I've also considered some other drivers instead. The CTS tweeter was not one of them. I'm surprised they work as well as they do. I might give it a try if my other ideas don't work out. Thanks Carl.

Vern, I took the grill and fiberglass (looked and felt more like lamb's wool to me) to see what was behind them. Nothing special, just a paper cone. I'm surprised it works as well as it does but it does do an excellent job. Is the AR5 dome midrange, the only difference I can tell better in every way? I wonder.

I still think the old style cast basket, alnico magnet cloth surroundwoofers sound better than the newer version. Somehow it seems to go deeper, even lower distortion, more musical. In my large basement a pair driven with a Pioneer SX950 receiver could put out an astonishing amount of deep bass.

[dynaco_dan]

Hi there

My first suggestion would be to use an adapter plate with the used 3 1/2" driver already attached, bought on ebuy.

I've bought several at reasonable prices, some included the T-nuts and bolts.

The drivers are commonly available with and without the plates and can be made with mdf or plywood or bought off ebuy as well.

Another untested option, in my opinion, might be to use an adapter plate with used AR-4X 2 1/2" drivers.

I would await others advice on my later suggestion.

[fiddlefye]

Hi there

My first suggestion would be to use an adapter plate with the used 3 1/2" driver already attached, bought on ebuy.

I've bought several at reasonable prices, some included the T-nuts and bolts.

The drivers are commonly available with and without the plates and can be made with mdf or plywood or bought off ebuy as well.

Another untested option, in my opinion, might be to use an adapter plate with used AR-4X 2 1/2" drivers.

I would await others advice on my later suggestion.

It looks like there are a few different ways to go about making nicely functional speakers out of these. I'm tempted to try the PRT path first as the drivers are cheap and plentiful and likely to be extremely reliable. I'm more interested in ending up with great-sounding and trouble-free speakers than with the collection quality aspect, most especially as nothing I would be doing would involve irreversible alterations.

The least likely scenario for me would be to replace with the original AR2a mids unless I could find an identical new replacement for them. Originals seem to me to be likely to be on their last legs and I gather the conversion by most accounts sounds better anyway?

Any advice on how to deal with the sad state of the pot wipers? What is the best way to deal with them? I've read in various threads about people who have cleaned them (though I gather this can be somewhat temporary even when successful) and those who have replaced them with L-pads. Has anyone used a modern day pot successfully instead? It strikes me as given that I will be replacing the original mid driver complement some sort of adjustability might be very useful, especially for those of us who are a bit sensitive to tonal balance and don't always have tone controls to work with.

What about crossovers? The originals will be long past their prime at the best and need replacing. What to do there?

I have a feeling these could end up being really pleasing speakers, well suited to my listening tastes.

[Carlspeak]

Download the AR3a restoration document which can be found in the library. There's a great write up in it about restoring or replacing the pots.

Replace the caps with Dayton filme types or similar caps (6.0 and 4.0 uF) You could also use 6.2 and 3.9 uF. You should order the caps the same time as the PRT's if that's the way you intend to go.

[dynaco_dan]

Hi again

I'm likely the last person here to substitute AR drivers with other types and brands.

After my saying that, because of the extremely fragile nature of the dual driver installation and the odds of finding an undamaged and physically undistorted cones, this would be a poorer choice.

Possible, but not necessarily the least costly and work.

Should anyone here choose to package up a pair of dual tweeters, all due caution to not touching any of the cone material.

Bolting them face to face requires a spacer.

Just the two touching face to face momentarily can remove some of or both cones.

[fiddlefye]

Hi again

I'm likely the last person here to substitute AR drivers with other types and brands.

After my saying that, because of the extremely fragile nature of the dual driver installation and the odds of finding an undamaged and physically undistorted cones, this would be a poorer choice.

Possible, but not necessarily the least costly and work.

Should anyone here choose to package up a pair of dual tweeters, all due caution to not touching any of the cone material.

Bolting them face to face requires a spacer.

Just the two touching face to face momentarily can remove some of or both cones.

I see you're a fellow Canuck. I agree. From what I saw of the mid drivers in my 2a's I'd say that the materials they were made from are beyond their real life expectancy at this point in time. Even if I did find a perfect set I'd probably be afraid to push them at all (not that I listen to my music that loudly, but there are moments ). If there were some contemporary match I'd be willing to try, but are the odds of that?

[fiddlefye]

Download the AR3a restoration document which can be found in the library. There's a great write up in it about restoring or replacing the pots.

Replace the caps with Dayton filme types or similar caps (6.0 and 4.0 uF) You could also use 6.2 and 3.9 uF. You should order the caps the same time as the PRT's if that's the way you intend to go.

That is quite the detailed document. If I can't figure things out from that I guess I'm pretty hopeless!