AR-2 Assessment

[Brad]

Hey everyone,

I just built my first pair of speakers from the ground up for the lady's sewing space and that inspired me to look into getting the most out of the AR-2s I bought on craigslist over a year ago. As I've been poking around this forum I've come to think that the previous caretaker did a pretty good job and that I perhaps came away with a steal and unwittingly benefitted from his labor of love.  But I am truly a novice with this stuff and wondered if you all might have some tips about what to look for and assess the state of AR-2s... They are definitely lacking in the high range, but I understand that's to be expected. I haven't worked up the courage to peak inside the cabinets yet, though I know that should probably happen if I'm really interested in a full assessment. 

 

Im attaching a couple photos for your appraisal. 

[Brad]

[genek]

How high off the floor are the speakers? The crossfired tweeters will give you pretty decent horizontal dispersion, but they need to be more or less at ear level.

[Brad]

They're at about 5ft. That was a deliberate choice, though maybe a mistake, as we do more music listening when we're standing. The room the speakers are in is open to the kitchen and dining room, probably 30ftx30ft or so. 

[stupidhead]

Hi Brad,

Nice set and congrats. There is reason to think someone has done something to these prior to your ownership, specifically the grille cloth. If I am not mistaken this is an example of oem cloth, a saran variation.

Yours has been reworked with what appears to be material (thin) found at Joann's fabric stores and is sort of close to the linen on later models.

As for highs being lacking, potentially the pot has been compromised over time, or someone has been inside and modified. the only way to know is to open it up. Be extremely careful with those tweeter assemblies as they are fragile. Entry by extracting woofer is the approach. Your pics do not show the terminal connections on the back, is the pot in place? Do you get any change in sound if you spin it?

[ra.ra]

Hi Brad, and welcome to the forum. I like the way you've got your AR-2's set up - - on sturdy shelves, in a horizontal position, at (standing) ear level, centered on the wall between the window mouldings with a vintage map displayed in between. It appears that the shelf boards might be loose laid inside those steel brackets, so I might suggest including some sort of thin cushion between shelf and bracket and/or shelf and speaker cabinet in order to discourage the possibility of rattling or rumbling that might result from LF output.

The comment about the grille cloth is a good one - - your speakers will look a whole lot better if you can get this installed tight and flat to eliminate the waviness that shows in your photo. This dual tweeter is fine, but it is generally not regarded as one of AR's finest driver selections, so you do want to try to get the maximum out of these for HF enjoyment. Your room appears to have mostly hard surfaces so perhaps that helps some.

You will need to get inside thru the woofer hole to explore this further. The single level control will need to be examined and assessed, and the capacitors should be checked and measured. The AR-2 was already popular before 1960, and some of the metal-encased oil-filled capacitors used in those early years often still measure and perform well and do not require replacement. Not sure how old yours might be - - your serial numbers appear to fall between 10 and 20,000, but you can often find date stamps on the drivers themselves. A few pics attached here - - I think these are all original AR-2 crossovers, so you can see the variety of component types used. A schematic diagram is also provided.

Just for consideration, this might be a perfect situation for adding some external super tweeters like shown in catalog page here.     

(Edit: I think the second x-o shown with paper-wrapped coil might be from the Heathkit doppleganger, the AS-2 speaker.) 

[Brad]

On 9/20/2017 at 9:26 AM, stupidhead said:

 

As for highs being lacking, potentially the pot has been compromised over time, or someone has been inside and modified. the only way to know is to open it up. Be extremely careful with those tweeter assemblies as they are fragile. Entry by extracting woofer is the approach. Your pics do not show the terminal connections on the back, is the pot in place? Do you get any change in sound if you spin it?

As a demonstration of my naïveté I'll ask, "You mean the little knob with the arrow on it?" 

Both are there, but I don't notice a change when I spin it. 

[Brad]

On 9/20/2017 at 10:13 AM, ra.ra said:

Hi Brad, and welcome to the forum. I like the way you've got your AR-2's set up - - on sturdy shelves, in a horizontal position, at (standing) ear level, centered on the wall between the window mouldings with a vintage map displayed in between. It appears that the shelf boards might be loose laid inside those steel brackets, so I might suggest including some sort of thin cushion between shelf and bracket and/or shelf and speaker cabinet in order to discourage the possibility of rattling or rumbling that might result from LF output.

 

Thanks for the tip, I do have some thin foam between the speakers and the shelves, but some between brackets and shelves would probably be a good idea too. 

When i build up the nerve to look inside i'll let you know how what I see compares to the pics you've shared. 

I'm very interested in the super tweeter idea, have people on the board experimented with building new ones to pair with the ar2?

[ar_pro]

You should notice a corresponding change in the higher frequency output as the level control is increased (clockwise) or decreased (counter-clockwise); also, there should be a "stop" in both directions - the knob should not merely spin.

If the knob does spin freely, consider tightening the knob more securely onto the level control shaft; it's also possible that the control shaft is broken, which would account for no change in HF output level.

If you're still not hearing a difference, the level control may be defective, and require repair or replacement.

This is assuming that no one's already been inside the box, and made a "repair".

 

There used to be a bit of a market for add-on tweeters - from the '50s on, there were deluxe Model 130 electrostatics from JansZen and much less expensive electrostatic models from Radio Shack - as seen in ra.ra's catalog image - and Lafayette Radio. In the '70s, MicroAcoustics brought out their very popular multi-driver "Microstatic" tweeter, and in the '80s, Radio Shack offered their Linaeum-sourced ribbon dipole tweeter as an add-on. These devices sold at widely-varied price points, and were generally seen to achieve slightly different ends. In addition to offering a slightly increased upper frequency range, they also had the ability to produce a wider spread of high frequencies.

Try searching the archives, and you'll find multiple posts on all of these tweeters, as some are still very much in use in member's systems. They turn up on eBay all the time.

Here's a photo of the JansZen, surrounded by four of the much smaller Microstatic units. The second image shows the Linaeum tweeter atop an Acoustic Research AR-91.