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AR tweeter swapping, will this work?

HepcatWilly

HepcatWilly

Just trying to be Hepful
I've posted an ad for an AR replacement tweeter that fits AR 2x, 2ax or 5.

Mine looks like this:
AR-Mine.png


The replacement offered by a fellow AKer looks like this:
AR-Red.jpg


Aside from the binding posts, is this possible to make this work in an LST/2?
Here's what I'm looking at:
AR-LST2.jpg


The binding posts on mine go from the front to the back of the tweeter, where they then clip on using the standard shovel-type wire clips. This looks like they might use something like a brass pinch post. Any ideas?

Thanks for your help!
 
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The lower dome tweeter in your post is from an AR-3. It is a larger dome and doesn't have the HF extension of the AR-3a (et al.) tweeter. I don't know how the impedance, efficiency, or Fs compare between the two. I can tell you that the AR-3 tweeter's magent is immense.
 
Don't mess with perfection...replace with exact (vintage) replacements...even if it takes you some time to find the right driver...you'll be happier and if you ever try to sell them in the future the new buyer will find it easier to meet your price knowing the drivers are correct. It's like matching serial numbers in vintage muscle cars.
 
I believe the AR5 and the LST tweeter are the same. The midrange fits the LST AR-3a and the AR-11. I wouldn't replace it with anything but the original driver. AR did alot of R&D on those speakers and all there speakers for that matter. The crossover networks are very elaborate and custom tailored to the individual drivers. The combo of the enclosure drivers and croosovers are what make the speakers sound the way they do. I am a big AR fan. Just my 2 cents though.
 
Sam Cogley said:
I'm not sure that fraud-filled can of worms is the best example...
Click to expand...
Agreed...but if you do your homework...it does pay off. I do the research to please me and not the next owner...that is why I end up keeping everything...:sigh:
 
I have never turned a pair of AR speaker loose and I don't think I ever will. I have too many AR speakers according to my girlfriend.
 
javelin79 said:
I believe the AR5 and the LST tweeter are the same. The midrange fits the LST AR-3a and the AR-11.
Click to expand...

Lots of confusion on this issue. To make matters worse, each individual driver went through a variety of changes over the course of its lifetime. Let me see if I can set this straight. Generally speaking:

The big phenolic dome tweeter is from either the AR-3 or an early AR-2a or AR-2ax. Despite the fact that the AR-3 is a 4 ohm system and the 2-series were 8 ohm, there is only one 4 ohm version of this driver.

The later 4 ohm paper dome tweeter was used in the AR-3a and AR-LST. Adding confusion, it was also used on the very last of the AR-3 to leave the production line and was used as a service replacement for the AR-3 tweeter.

The 8 ohm paper dome tweeter was used in the AR-5, AR-LST2, and later AR-2ax and AR-2a. THIS IS THE ONE THE OP IS LOOKING FOR FOR HIS LST2.

There were two different 4 ohm cloth dome tweeters (the later version used ferrofluid) used in the AR-11 and AR-10pi. Just to confuse the issue further, this style of tweeter (if not, in later years, the same model number) was the service replacement for the AR-3a and AR-LST from 1976 until the early 90s. Some of the last of the AR-3a may have been equipped with this tweeter from the factory and many wound up being used in AR-3a and AR-LST as service replacements. The most recent version of this tweeter was used in the AR-3a Limited in 1991.

All clear?

Since somebody brought up midranges:

There's the 4 ohm one from the AR-3. Because the 4 ohm paper dome tweeter was used at the end of the AR-3 run, the cloth surround woofer was used in the early AR-3a (just as the foam surround woofer was used in later AR-3) and at some point the AR-3 migrated to the later cabinet style, this midrange is the only reliable distinguishing feature of the AR-3.

There's the different 4 ohm midrange in the AR-3a and AR-LST.

There's the 8 ohm one (visually identical to the 3a midrange) in the AR-5 and AR-LST2.

There's a different 4 ohm one yet in the AR-11 and AR-10pi. Like the AR-11 tweeter, it may have been used in the 3a at the end of its run, and was used as a service replacement for the 3a and LST.
 
AR's 4 and 8 ohm paper dome tweeters cause a lot of strife these days.

People will tell you different things:

- They sucked from the beginning
- They suck now because they're old and the materials are failing
- More and more, they're measuring unpredictably because of age
- They're all doomed to die from materials failure

All or none of the above may be valid points (I'm still a fan of how the ones in my AR-2ax from 1970 sound), but AR enthusiasts are desperate for a solution. The current 4 ohm service replacement from AB Tech is derided as mediocre and overpriced, but it just happens to fit the hole. It can be made listenable in an AR-3a or AR-LST by adding a .07mH inductor in parallel. The AB Tech tweeter hasn't been in stock in months, however, and it isn't suitable for the 2a, 2ax, 5 or LST2.

Over at Classic Speaker Pages, RoyC has been championing the use of the 6 ohm HiVi Q1R tweeter to replace the AR paper dome tweeters. It fits in the existing cabinet hole with no modification. Feedback and experimentation continue, but right now, he's recommending it (with a .1mH parallel inductor) as a replacement for both the 4 ohm and 8 ohm versions of the AR paper dome tweeter. I think it's likely that this fix will be enshrined in the next revision of CSP's "Restoring the AR-3a" document.
 
HepcatWilly said:
Whew. That was like a verbal shell game.
Thanks for pointing out that the ABTech tweet won't work, that was an option. What are your thoughts on the Vifa 3/4" soft dome tweeter at Parts Express?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-500

Hope I'm not leading this too far astray.
Click to expand...

Not at all.

You'd need to fabricate a faceplate for the Vifa. There's no reason why you can't give it a go, especially if you're willing to play with changing the capacitor value and/or adding an inductor.

Vintage AR speakers are both a means of sound reproduction and a collectible with a rabid following. Aficionados (yours truly included) are gaining a reputation for getting their panties in a twist over non-originality. If you're only looking to please yourself, you might well be able to hit upon something you like better than the original tweeter, but you'd probably hurt the monetary value of your very desirable pair of LST2. If resale is a possibility, any deviation from bone stock usually drives down the sale price. If the restoration or modification is something that isn't "community approved", more so.
 
On those speakers i would just make sure any upgrades are reversible to original for resale value.
 
My plan exactly kfa888!

I have several pairs of Allisons and Acoustic Research. I wholeheartedly agree with the above statements.
 
I think you will be happy with your tweeter Willy, it is identical to the ones on the lst-2 photo.
 
Hate to rain on your parade, but "looking identical" isn't good enough. It must be identical!

As Winters explained (and nice job Winters!), the 3/4 inch dome came in two flavors 8 ohm and 4 ohm (yet they look identical). Now, the 4 ohm version was used in AR-3's, AR-3a's and LST's. This flavor will NOT work in your LST/2's.

You can tell by measuring the dc resistance.

Here's the problem ... the LST/2 has three surfaces and three tweeters. Each tweeter should put out exactly the same amount of sound.

Now, those three tweeters are wired in parallel!!! If you use a 4 ohm version, it will suck all of the current and dominate the other two. Further, it will drop your impedance in the tweeter range to 2 ohms!

Sorry ...

Regards,
Jerry
 
It is a 8 ohm tweeter, with the identical back wiring. It is a late Teledyne era AR-2ax tweeter.
 
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