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AR-3 tweeter and midrange modification


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Hello

I have an AR-3 speaker with the tweeter and midrange both dead. 0.0 DCR when I disconnected the yellow centre wire of the terminal strip and measured both drivers. I don't know how this happened, bad luck, stupidity or a combination of both.

I have read in these forums that the HI-VI QR-1 tweeter is a plausible replacement for the AR-3a tweeter. Is this also true for the AR-3?

Is there a suitable substitute for the midrange?

I am asking this because replacing both the tweeter and midrange with original drivers plus shipping to Canada is going to cost upwards to near $200, which is more than I am willing to spend on one speaker for 50 year old drivers. I understand that I will have to modify both speakers, but if the numbers are right, and the sound is somewhat close to the original, (I am not too concerned about the dispersion) then I think it is worth a go.

Am I a monster?

Stan

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Hello

I have an AR-3 speaker with the tweeter and midrange both dead. 0.0 DCR when I disconnected the yellow centre wire of the terminal strip and measured both drivers. I don't know how this happened, bad luck, stupidity or a combination of both.

I have read in these forums that the HI-VI QR-1 tweeter is a plausible replacement for the AR-3a tweeter. Is this also true for the AR-3?

Is there a suitable substitute for the midrange?

Stan

Hi Stan,

The later AR-3 used the same midrange as the 3a. If necessary, the Library has info on a slight crossover change that can be used with this later midrange driver. I have some extra midrange drivers pulled from Cello Amati speakers you may be able to use. These were manufactured by AR, and are physically and electrically the same as the 3a midrange, but with no metal grille. Some forum members have used these in AR-3s and found them to be satisfactory.

The HiVi Q1R tweeter dome is about the same size as the AR-3 tweeter dome, and should work as well or better in the 3 as it does in the 3a, 2ax, and 5. Try it with an 18ga, .05mh parallel inductor.

(It can be glued to the back of the tweeter with a small spacer.) The Q1R magnet is shielded and won't affect the inductor.

PM me if I can be of assistance.

Roy

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Hi Stan,

The later AR-3 used the same midrange as the 3a. If necessary, the Library has info on a slight crossover change that can be used with this later midrange driver. I have some extra midrange drivers pulled from Cello Amati speakers you may be able to use. These were manufactured by AR, and are physically and electrically the same as the 3a midrange, but with no metal grille. Some forum members have used these in AR-3s and found them to be satisfactory.

The HiVi Q1R tweeter dome is about the same size as the AR-3 tweeter dome, and should work as well or better in the 3 as it does in the 3a, 2ax, and 5. Try it with an 18ga, .05mh parallel inductor.

(It can be glued to the back of the tweeter with a small spacer.) The Q1R magnet is shielded and won't affect the inductor.

PM me if I can be of assistance.

Roy

Hi Roy

Thanks for your reply. I certain was going to buy the HiVi tweeter and perhaps take you up on your offer for the midranges, but I made a decision to spring for original AR drivers one last time. Next time, substitutions!!

I bought (for more than I wanted to spend) NOS AR tweeters and midranges from the Canadian Audio classifieds site.

They look brand new and from reading the restoring document look like original parts dating from the 70's. My woofer in the AR3 has a serial number 1-2100030B which indicates that the speaker was updated to a AR3a woofer but retained the AR3 midranges and tweeters as well as the AR3 label on the back.

So it looks like I will be upgrading the AR3 to a AR3a. Do I have to change out the crossover also or can I use the original AR3 crossover? Mine does not have the additional 6uF cap, but does have replacement L-pads. I may still bypass the L-pads.

Here is a photo of what I purchased. I was actually looking forward to messing around with the new tweeters etc, but a little voice inside of me said to do the right thing.

Soon, I certainly will be picking your brain for more advice once I start this project if that is alright.

Regards,

Stan

Tweeters_and_Midranges.bmp

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Hi Roy

They look brand new and from reading the restoring document look like original parts dating from the 70's. My woofer in the AR3 has a serial number 1-2100030B which indicates that the speaker was updated to a AR3a woofer but retained the AR3 midranges and tweeters as well as the AR3 label on the back.

So it looks like I will be upgrading the AR3 to a AR3a. Do I have to change out the crossover also or can I use the original AR3 crossover? Mine does not have the additional 6uF cap, but does have replacement L-pads. I may still bypass the L-pads.

Stan

Stan,

It is always more fun to use original AR drivers when possible.

It appears you have some interesting options, but the one you no longer have is the AR-3 . The woofers, as well as your new tweeters and mids, are all from the AR-11 era....which are very similar to the later AR-3a Limited drivers. With the exception of the mids, they are different than that of the AR-3. The capacitors mounted on your tweeter magnets were an attempt to adapt the AR-11 tweeter to the AR-3a. IMO, Since you already have l-pads instead of pots, your best option is to create a pair of AR-3a Limiteds, which was essentially equipped with AR-11 drivers. Whether you turn them into AR-3as, 11s, or Limiteds, a more elaborate crossover is required.

Bypassing the l-pads, especially with the drivers you have now, will not provide the sound of any of the above mentioned speakers.

Roy

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  • 4 weeks later...
... Is there a suitable substitute for the midrange? ... Am I a monster? Stan

Stan did right and he is no monster. But I am a monster.

About the same time Stan was working on his AR3's, I was working on some newly acquired AR3's from about 1960 and 1961. I don't think they'd ever been opened! I cleaned the pots, replaced the caps, detailed the walnut veneer and cleaned the grill cloths, and applied some Permatex gasket sealer (thinning was necessary) to the woofer fabric surrounds. But one midrange driver was dead. I did not want to search and spend and use a fifty year old replacement midrange. Halloween was approaching, so I became a monster.

I purchased a pair of inexpensive Dayton 2-inch dome midrange speakers (on sale at only $25 each) and installed one of them.

Here is the catalog description - Dayton DC50F-8 2" Dome Midrange - High quality 2" dome midrange that offers outstanding performance at a reasonable price. The advantages of dome midranges include lower moving mass and superior off-axis frequency response. The Dayton dome midrange has been used in many excellent DIY speaker systems. Specifications: * Power handling: 80 watts RMS/115 watts max * Voice coil diameter: 2" * Impedance: 6 ohms * Re: 4.5 ohms * Frequency response: 500-6,000 Hz * Fs: 384 Hz * SPL: 90 dB 2.83V/1m, 89 dB 1W/1m * Dimensions: Overall Diameter: 5-3/4", Cutout Diameter: 4-1/2", Mounting Depth: 2-3/4", Magnet Diameter: 4-1/8", Magnet Height: 2-1/4".

The dimensions were ideal, just perfect, but I had to use new wood screws. The specifications were not ideal. Tom Tyson cautioned me that while I could pad down these more sensitive speakers, the lesser frequency response (an upper roll off of 7500 would be right) would provide a different and possibly inferior sound. That is how it worked out, the sound in the upper mid range is lacking.

I wonder, am I doomed to remain a monster, or is there a modification of crossover components that can provide an appropriate upper crossover frequency for the new midrange and original tweeter? I'd be grateful for suggestions.

David

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I wonder, am I doomed to remain a monster, or is there a modification of crossover components that can provide an appropriate upper crossover frequency for the new midrange and original tweeter? I'd be grateful for suggestions.

David

Hi David,

The AR-3 crossover is allowing the original mids to operate near the highest limits of their upper frequency range, so if your new mids are not getting there with the existing crossover, it is unlikely they can be coaxed to do much better than they already are. The only thing you can try is to remove the .05+/- mh inductor in series with the midrange, assuming your era crossover has one....but it is unlikely to solve the problem.

I suggest obtaining used AR replacements, and cutting your losses. There are plenty of them around, as discussed above. Replacing drivers in an existing design with something different is seldom as easy as screwing the replacement into the cabinet. At least you did not purchase expensive drivers. It is not uncommon for a well meaning tinkerer to acquire very pricey "modern" replacement drivers, and end up with a compromised system, or unusual paperweights.:blink:

Roy

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Hi David, ...so if your new mids are not getting there with the existing crossover, it is unlikely they can be coaxed to do much better than they already are....Roy

Thanks, Roy,

My hope was not to coax more from the new midrange speakers, but to see if the original tweeters can take up the 6000-to-7500 Hz chore. Does that make sense?

Tinker Monster Sfffz

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Thanks, Roy,

My hope was not to coax more from the new midrange speakers, but to see if the original tweeters can take up the 6000-to-7500 Hz chore. Does that make sense?

Tinker Monster Sfffz

TMS, :blink:

OK...That would require some experimentation with a larger capacitor in the tweeter circuit. Using an l-pad instead of the original pot for the tweeter will also lower the tweeter's crossover point somewhat. Be advised that lowering the crossover point will also lower the tweeter's power handling capability.

Of course, you are now traveling further into the realm of re-designing the AR-3, Mr Monster. If that is acceptable to you, and the original tweeter does not cooperate, the HiVi Q1R with an appropriate parallel coil (in this case I would start with an 18ga .1mh coil), can easily reach the upper midrange. Without measurement equipment, and crossover experience, it is still a crapshoot, however, and will likely require a fair amount of experimentation. Try not to do anything that cannot easily be undone.

Roy

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TMS, :rolleyes: ... Roy

Aw, you kids, talking in abbreviations. I don't know whether TMS means Tinker Monster Sfffz or That Makes Sense.

My AR3's, modified, corrupted, perverted as they are do sound good, almost wonderful. It has helped that I changed amplifiers, played them several days continuously, and struggled to keep the pots in shape. No L-pads for me.

But I am not a purist restorer. And I do wish to see my Venus de Milo with arms. Translation: it is imaginable that today's 2-pound, $25 dome midrange could be an improvement on the the 9.9-pound 1961 AR. Digression: as a product of 1961 - my high school graduation year - I can hope my kids will be smarter and more productive than me.

My hope is that a change in capacitors or coils could smooth out my modified speaker, lowering the upper crossover point, letting the AR hi do some of the work of the on-the-cheap mid.

Now I gotta defer the project and listen to some music.

Roy, thanks.

David

P.S. Months later, I brought the AR midrange to N.E. Speaker in Stoneham, MA, for repair. I feel better, my conscience feels better, and the music is better!

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I don't know whether TMS means Tinker Monster Sfffz or That Makes Sense.

Digression: as a product of 1961 - my high school graduation year - I can hope my kids will be smarter and more productive than me.

My hope is that a change in capacitors or coils could smooth out my modified speaker, lowering the upper crossover point, letting the AR hi do some of the work of the on-the-cheap mid.

Roy, thanks.

David

Given MY high school graduation year was 1967, "TMS" was definitely referring to da monster. :blink:

You're welcome, David....Feel free to send a message through the forum (um, PM) if I may be of assistance.

Roy

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  • 1 month later...

Hello to all;

Its been a while since I last posted. Since then, with the tremendous assistance from Roy C., I modified my AR-3's into a pair of AR-3a Limiteds. All NOS tweeters and midranges. All the cross-overs were completely rebuilt and new pots were installed. Cost more than I wanted to originally spend, but I figured this is the very last kick at the can.

All I can say is I am really glad I went this way. Wow! If this is close to what they originally sounded like, then all I can say is that a new pair of AR-3a speakers could still blow you away in any showroom. I never thought that I would see the day when I would be turning down the pots on a set of AR speakers. The highs and mids are very prominent when the pots are maxed out. I know that they will mellow out after a few hundred hours but what a kick!

Thanks to all the experts out there that contribute to these pages. Gave me the confidence to dive in a transform these old girls into a pair of red-hot Mamas. (bet you've never heard of AR-3's described as Red-Hot Mama's before).

Stan

BTW: I'm now the owner of a extra pair of AR-3 tweeters (working) and one dead tweeter, one dead midrange and one good midrange (Tonegen replacement driver). Plus AR-3 cross-over parts.

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  • 3 weeks later...
Stan,

It is always more fun to use original AR drivers when possible.

It appears you have some interesting options, but the one you no longer have is the AR-3 . The woofers, as well as your new tweeters and mids, are all from the AR-11 era....which are very similar to the later AR-3a Limited drivers. With the exception of the mids, they are different than that of the AR-3. The capacitors mounted on your tweeter magnets were an attempt to adapt the AR-11 tweeter to the AR-3a. IMO, Since you already have l-pads instead of pots, your best option is to create a pair of AR-3a Limiteds, which was essentially equipped with AR-11 drivers. Whether you turn them into AR-3as, 11s, or Limiteds, a more elaborate crossover is required.

Bypassing the l-pads, especially with the drivers you have now, will not provide the sound of any of the above mentioned speakers.

Roy

This thread has been very interesting. In 1990 I stupidly blew the tweeters in my AR-3a improved. AR sent me replacement tweeters with the in line capacitor, 200011-1 sticker with 200013-1 over them. AR literature from the 1970s says 3a and 3a improved differ only in the crossover. Should I wire them through the capacitor or not? Thanks.

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This thread has been very interesting. In 1990 I stupidly blew the tweeters in my AR-3a improved. AR sent me replacement tweeters with the in line capacitor, 200011-1 sticker with 200013-1 over them. AR literature from the 1970s says 3a and 3a improved differ only in the crossover. Should I wire them through the capacitor or not? Thanks.

Hi Mike,

I presume you have been listening to them without the cap? If so, using the cap will cut down tweeter output quite a bit from what you are used to listening to, but would be more as originally intended by AR. Another approach would be to not use the cap, but try a parallel .1mh to.15mh coil across the tweeter. That would make the tweeter circuit similar to the AR-11 and AR-3a Limited models. They both used the same tweeters as your replacements.

Roy

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Hi Mike,

I presume you have been listening to them without the cap? If so, using the cap will cut down tweeter output quite a bit from what you are used to listening to, but would be more as originally intended by AR. Another approach would be to not use the cap, but try a parallel .1mh to.15mh coil across the tweeter. That would make the tweeter circuit similar to the AR-11 and AR-3a Limited models. They both used the same tweeters as your replacements.

Roy

Hi Roy,

Thanks for the reply. As you suggest I have been listening to them without the cap. Until recently I have also been listening to them with the mids in the wrong phase! Now I know better, with the mids in correct phase the speakers seem more detailed but have developped a harshness, particularly on female voices. Wiring the tweeters through the cap seems smoother and more natural. Should I continue using the cap or is the wiring with the coil that you suggest a better system? As far as possible I would like them to sound as AR intended the AR-3a improved to sound.

Thanks for your help,

Mike

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Hi Roy,

Should I continue using the cap or is the wiring with the coil that you suggest a better system? As far as possible I would like them to sound as AR intended the AR-3a improved to sound.

Thanks for your help,

Mike

Mike,

You are probably as close as you are going to get to AR's "intended" sound by using the cap with the later tweeter. If you like it, I see no reason to change it. The parallel tweeter coils used in the AR-11 and 3a Limited were used with capacitors of different values, so it will be hit or miss trying to find a coil value for the AR-3a Improved that sounds any better to you.

Roy

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Mike,

You are probably as close as you are going to get to AR's "intended" sound by using the cap with the later tweeter. If you like it, I see no reason to change it. The parallel tweeter coils used in the AR-11 and 3a Limited were used with capacitors of different values, so it will be hit or miss trying to find a coil value for the AR-3a Improved that sounds any better to you.

Roy

Roy thanks for your time with this. It's much appreciated.

Mike.

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