Bungled AR 2ax repair

[RoyC]

4 hours ago, JKent said:

Hi Roy

Maybe I misunderstood. I was under the impression that the Hi-Vi was a good replacement for the 3a tweeter but not 2, 3, 2ax, 5.... Am I mistaken about these? If the Hi-Vi can be used in those, fine.  Your rebuilds look interesting.

-Kent

Sure, it is being used in all of them using the same .05mh parallel coil. Larry has sold hundreds with the coil on the back as a "drop-in" replacement, but I advise reducing the capacitor value a bit if the owner is inclined to do that kind of work. 

The rebuilt tweeters in my photos seem to work well with just the added coil, and no cap change... and are available as 4 or 8 ohm versions. These rebuilds have a similar dispersion advantage as the original tweeters, with a non-recessed 3/4" dome. I've been experimenting with damping material under the dome.

Roy

[rjr513]

Like Roy I've been experimenting with the same rebuilds in my Ar2ax, I used the same .05mh coil, also... I used the 8ohm version with a dcr of 6.2 ohms with my Fluke meter I then went ahead and added a series 6uf carli mylar to the 3.9uf  to give me around 2.64uf In the tweeter capacitance...  

[Lucky Pierre]

You guys are the best.

[JeffPro]

Every morning (and some evenings) this past week I grab a cup of coffee and with cat in tow proceed to exercise the AR's with a wide range of vinyl. The Scott 355r (a SS Korean issue rated at 45 watt rms) receiver the AR's are mated to is really not doing those speakers justice. The receiver had not been used in a while, mainly because when used at the shop at higher volumes the receiver would cut out, and then come back on at a lower volume. I did the non tech superficial clean of the receiver and used Deoxit on the controls, but that did not help what ever else is going on.  I plan on finding a replacement, but deciding and finding the right one is not going to be easy. Still need to do a separate post on this to get some opinions.

What I found is if I keep the volume between 1/4 and 1/2 (closer to half they start sounding better) and boost the tone controls on the receiver,  the music sounds fuller and more balanced to my ears. Not exactly what I think is proper or healthy for the system, but at the lower volume level which I would be listening to them most often, they still sound a little flat. My theory is that a reconditioned tube or better quality reconditioned SS amp will help with this.

I also need to put more sound absorbing materials in my little listening room. Angling the speakers toward me seem to help a bit.

I am excited to hear about the work Chris1this1 is doing and anxiously await to hear more feedback.

[Robthomp]

On 3/15/2017 at 2:03 PM, RoyC said:

The rebuilt tweeter will have more output, Rob. Replacement or repair of these tweeters should be done in pairs for best results.

Roy

I sent the other tweeter to Chris to have it rebuilt.  Now they are balanced.

[lakecat]

On ‎3‎/‎16‎/‎2017 at 2:24 PM, RoyC said:

Hi Kent,

I guess it depends on your definition of "suitable". The HiVi Q1R is a modern tweeter, as was the AB Tech replacement, and, imo, both have been made (with a crossover mod) to be suitable. Many modern tweeters have been tested and considered, and other than AR-11 onward AR tweeters (which also require a similar crossover modification), there is nothing more "suitable" in the "modern" category. As discussed before, the original AR dome tweeter has very unique construction materials and properties. There will never be a "modern" drop-in equivalent unless some manufacturer decides to specifically develop and manufacture a tweeter with identical mechanical and electrical characteristics...which is extremely unlikely at this point. The rebuilt tweeter Chris is providing, based on the construction materials alone, is likely to be as close as anyone will ever get to providing a modern version of the original tweeter.

When Vintage AR/Larry returns from vacation, we will be installing Chris-rebuilds in LST's and 3a's, and will get our first opportunity to hear how they actually integrate with these speakers. On the bench his rebuild shows much greater overall output and somewhat greater extension into the upper midrange frequencies than all the functional original tweeters we had on hand, though not to the same degree as the modern tweeters mentioned above. It will be interesting to hear how it handles the all important overlap with the midrange driver.

Attached are a couple of photos of original tweeters I've rebuilt using a "modern" 3/4 inch dome/voice coil assembly (shown in a couple of AR-5's awaiting cabinet restoration, and later tested in a pair of 3a's.). It actually works quite well, and I would consider it a "suitable" replacement, but it still requires a parallel coil to tame extension into upper midrange frequencies...and like any rebuild, requires an original tweeter carcass.

Roy

 

Roy......when you get your testing done, could you post on here your findings? I am going to refinish the LST's soon when it gets warmer here and just may invest in getting those tweeters done as these bad boys are staying here....:) Still looking for an amp for them. Thanks!

[lakecat]

And to Jeff....thanks to your thread, I learned the AX also had that AR3 tweeter in it. I only had one pair that I redid and it had a different tweeter. I thought the 2a was the only other speaker to have that tweeter....:)

[JKent]

10 hours ago, lakecat said:

the AX also had that AR3 tweeter in it.

Yes, but only the very early 2ax. I had those in my 1st pair but one was bad so I replaced both with Roy's help, with a pair of the later 2ax tweets.

-Kent