AR-2ax Tweeter Replacement

[Steve Lanich]

Hello, for my first post here I decided to start a new thread rather than revive an old one, I hope that's OK. I've re-foamed, re-capped, and cleaned pots, and now I need new tweeters for my two circa 1976 AR-2ax. After speaking with Carl at Carl's Custom Loudspeakers and reviewing info here, I plan on ordering the HiVi Q1R (currently out of stock at PE), along with the 0.05mH inductors recommended by RoyC. What is not clear to me is exactly how to connect and securely mount the inductors. And, what exactly does this inductor do?

Thanks to all who make this a very helpful site.

Steve Lanich

Bellefonte, PA

[RoyC]

Hello, for my first post here I decided to start a new thread rather than revive an old one, I hope that's OK. I've re-foamed, re-capped, and cleaned pots, and now I need new tweeters for my two circa 1976 AR-2ax. After speaking with Carl at Carl's Custom Loudspeakers and reviewing info here, I plan on ordering the HiVi Q1R (currently out of stock at PE), along with the 0.05mH inductors recommended by RoyC. What is not clear to me is exactly how to connect and securely mount the inductors. And, what exactly does this inductor do?

Thanks to all who make this a very helpful site.

Steve Lanich

Bellefonte, PA

Welcome to CSP, Steve...

Basically, the inductor provides a by-pass, shunting lower frequencies around the tweeter. It modifies the Q1R's response to more closely resemble that of the original tweeter.

Attached are some photos of a Q1R being set up for installation in an AR-5 cabinet, which is essentially the same as the AR-2ax cabinet with the exception of the midrange hole. 22ga wire is connected to the inductor leads by 3/16" push-on connectors. The 22ga wire leads are threaded through small holes drilled in the plastic faceplate, and the connectors are attached to the tweeter tabs. The Q1R is shielded, so very little space (such as a piece of cardboard, as shown) is needed between the magnet and inductor to keep it from affecting the inductor. Hot glue or Goop glue (any variety) will work very well to hold the spacer and inductor on the back of the tweeter. A tiny dab of glue and/or electrical tape (to resemble the original tweeter installation...not really needed) will seal the holes through which the wire leads emerge from the tweeter faceplate.

An advantage to implementing the Q1R in this way, is that it retains the ability to install an original tweeter at any time. No changes are made to the cabinet or original crossover. The Q1R faceplate does not require an adapter ring, or any cabinet hole modifications!

I have some extra Q1R tweeters as well as inductors. Send me a PM if I can be of further assistance.

Roy

[genek]

If Steve's 2ax's are from the 75-76 production run, they'll have back-wired tweeters. He won't need to drill the faceplate.

[RoyC]

If Steve's 2ax's are from the 75-76 production run, they'll have back-wired tweeters. He won't need to drill the faceplate.

Good point, Gene!

Steve, if you are back-wiring them, the internal black wire goes to the + terminal of the Q1R, and the internal yellow wire goes to the - side. This is the reverse of the original tweeter, as the added coil necessitates a change in polarity.

Roy

[Steve Lanich]

Whoops, I guess it depends on your definition of "circa" , because mine are not back-wired, they do have the tweeter tabs and fragile tinsel on top. Another example of 1970s memory loss.

I like the idea of preserving the front tweeter tabs and I have no problem drilling holes through the plastic faceplate of the Q1Rs. Thanks to Roy and Gene for the explanations!

Roy, expect a PM from me.

Steve Lanich

Bellefonte, PA

[RoyC]

Whoops, I guess it depends on your definition of "circa" , because mine are not back-wired, they do have the tweeter tabs and fragile tinsel on top. Another example of 1970s memory loss.

I like the idea of preserving the front tweeter tabs and I have no problem drilling holes through the plastic faceplate of the Q1Rs. Thanks to Roy and Gene for the explanations!

Roy, expect a PM from me.

Steve Lanich

Bellefonte, PA

Drilling the holes can be tricky due to the small Q1R holes on one side, and the edge of the faceplate on the other. If you don't have a drill press, a small pilot hole is necessary to have any chance of success. I use a 5/16" Forstner bit for the final holes.

Another option is to simply use the Q1R holes, using small #6 black deep thread pan head screws, also sold by Parts Express (part # 081-435). The attached photo shows a Q1R in an early 2ax cabinet, which was converted to back-wiring. The original cabinet holes can be filled with putty under the faceplate.

Roy

[Chebu70]

Another noob here but between the recent inheritance of some ar-5's and the wealth of information on this site, you guys have me hooked on the vintage audio gear. I think I have most of the information I need to wrap up the repairs on the ar-5's but have a couple questions I'm sure you'll have no trouble answering.

1. I ordered the hi-vi tweeters and .05mh inductors from prts express. Do i understand correctly that the u doctor should wired in parallel?

2. Do I need to reverse the polarity on the crossover wires

3. I'm using the factory pots as of now... I cleaned up the speaker and they seem to look and work like new. Will the .05mh inductor work with the factory pots and caps or should I plan to replace those as well?

I got the refoaming done already and have already played them sand 1 tweeter on a kr6400 and was blown away listening to company of strangers. Can't wait to get them matched and fully operational.

Apologies if these questions have already been asked and answered... I'll accept any new guy hazing I may have earned with this post.

- Sean

State College, Pa

[JKent]

Hi Sean and welcome. No hazing here--we were all noobs once and even oldies like me need help.

1. yes--the inductor is wired in parallel, across the terminals of the tweeter. Look at Roy's photo in Post 2. That tweeter was modified for front-wiring but that doesn't matter
2. You can experiment with polarity of the tweeters to see which sounds better to you.
3. Although the new tweet/coil will work with the old pots and caps, you should at least clean the pots (take them apart--there are instructions in several places). As far as the caps go, you should probably replace them unless they are Sprague compulytics, which may still be good.

According to Carl's schematic in the Library, the 5 uses one 4uF, one 24uF and one 72uF cap per speaker. Madisound has some choices:

• For the 72uF you could use Bennic electrolytics: 50uF + 22uF in parallel (cost about $2.80 per speaker) http://www.madisoundspeakerstore.com/bennic-electrolytic-capacitor-100vdc/
• Another 72uF option, if you don't mind wiring up 8 caps in parallel: use seven 10uF caps ond one 2uF. Cost about $4.50 per speaker http://www.madisoundspeakerstore.com/surplus-capacitors/
• for the 24uF use two of the 10uF and two 2uF surplus caps, cost $1.80 per speaker.
• or for the 24uF use a Solen 25uF (close enough) for $9.90 per http://www.madisoundspeakerstore.com/solen-capacitors/solen-25-mfd-fast-cap-400v/
• you can use any 3.9 or 4uF cap--they're all cheap. Combine two of the surplus caps for $.60, a Carli for 1.35, Solen for $3.05, or a Clarity PX for $4.60

If I were doing it I'd probably buy all surplus caps: 18) 10uF and 10) 2uF. Total cost $14.30 for 2 speakers. Madisound also has L-pads if your pots are beyond cleaning.

I have not worked on 5s myself but have worked on similar 2ax's and 3s. Maybe Roy will have specific advice regarding his tweeter mod and the 5s.

Kent

[RoyC]

I would only add that If you are replacing the caps, reduce the 4uf cap to a 3uf cap to bring the HiVi a bit closer to the original tweeter. Reversing the tweeter polarity is the best way to start out.

Roy

[Chebu70]

Thanks for laying this out in laymans terms! Do I understand correctly then that the .05mh inductor should be fine with factory caps and pots? I ask because I think I saw Roy's original recommendation was for a .07mh coil. I'm sure at some point I'll change everything out anyway but I getting a little anxious to get these fired up this weekend. Thanks again guys.... Absurdly fast responses.

- Sean

[RoyC]

Thanks for laying this out in laymans terms! Do I understand correctly then that the .05mh inductor should be fine with factory caps and pots? I ask because I think I saw Roy's original recommendation was for a .07mh coil. I'm sure at some point I'll change everything out anyway but I getting a little anxious to get these fired up this weekend. Thanks again guys.... Absurdly fast responses.

- Sean

Hi Sean,

Yes the .05mh inductor (18ga) will work fine with the factory caps and pots. Initially we were playing around with values between .05mh and .1mh, but the .05mh was preferred most often. It is also readily available.

Roy

[JKent]

I would only add that If you are replacing the caps, reduce the 4uf cap to a 3uf cap to bring the HiVi a bit closer to the original tweeter. Reversing the tweeter polarity is the best way to start out.

Roy

The Solen comes in 3uF:

http://www.madisoundspeakerstore.com/solen-capacitors/solen-3-mfd-fast-cap-400v/

[Chebu70]

Thanks for the tips fellas! I got the 5's running this weeked and I'm blown away by what I've heard thus far. Can't wait to pick up the new people hell and angels vinyl in march. I still need to do the caps and probably l-pads but should tide me over until now.

[JKent]

Glad you're enjoying them! I have 2 more thoughts:

1. I forget whether the HiVi tweeter is metal or plastic on the back but if it's metal, you'll want to put some tape on the bare wires to prevent accidental shorting (if plastic no problem. I just can't remember)
2. looks like the cabinets are in good shape but have some fading and staining. An easy fix is Howard Restore-a-Finish, available at Home Depot and some hardware stores. It comes in Walnut, Dark Walnut and other shades. Wipe it on with a rag, wipe it off. For stubborn areas you can use 0000 steel wool but usually a rag is fine. Here's a video (below). Afterward you can use either Howard Feed n Wax or a coat of Watco Danish Oil (also available in a few shades). Again, easy to use: Wipe on/wipe off. Do not use any kind of polyurethane or varnish. Another nice finish is Minwax Antique Oil but this has some shellac or something in it and leaves a harder, shinier finish than the Danish Oil. The original finish was boiled linseed oil, and the Danish Oil is virtually identical to the original. Antique oil is nice but not as authentic.
3. Here's another how-to: http://www.minksemporium.com/Demonstration.html

Kent

[dynaco_dan]

Hi there

This would appear to be a miracle liquid.

My only warning here is about the use of steel wool.

No or less concern if no drivers are mounted in the cabinets.

If the drivers are still mounted in the enclosures, cloth, cardboard or sheet paper should cover the drivers because of the drivers strong magnets.

[JKent]

Good point Vern.

I should pass along this information: Although I have used the products described above with no problem, Roy told me of someone who said he could not use Watco Danish Oil over Restor-a-Finish. I wrote to Howard and got an immediate reply to several questions, which I'll quote here (my question, followed by reply in italics):

1. Can I use Watco Danish Oil over R-A-F? "Not recommended."

2. Can I use boiled linseed oil over R-A-F? "Usually yes, after it has cured/dried for a week or so. As long as it is real linseed oil".

3. Is there any component of R-A-F that would interfere with a rubbed oil finish? "No".

4. Are you still comfortable using Minwax Antique Oil over R-A-F? "I always use Howard Feed-N-Wax or Howard Orange Oil to maintain my collections. However, as long as the Watco or Minwax product you want to use does not contain any urethane or varnish component to it…it will be compatible with Restor-A-Finish."

"None of the Howard Products contain any silicone oil. Never has, Never will. The reason you shouldn’t apply a resign or clear coat type finish over Restor-A-Finish is only because of the incompatibility of the solvents and oils in Restor-A-Finish. These solvents may not allow the clear coat resign to dry properly. Not always but sometimes. Any “oils” that are strictly oil…or oil and wax combinations are just fine over Restor-A-Finish. If you are determined to apply a clear coat to a surface…do not use Restor-A-Finish. That surface needs to be cleaned, sanded and prepped for a new finish. However, that said, some of my antique dealers do use a product by Mohawk called Perfect Blend acrylic lacquer. Mohawk claims it will dry over wax and oil. It comes in satin, gloss and semi gloss I believe. I hope this helps. I am a true believer in Restor-A-Finish and then a quality wax like Feed-N-Wax or Citrus Shield Paste Wax."

So... Although I have used both Minwax Antique Oil and Watco Danish Oil over Howard Restor-a-Finish, these are not recommended because they contain varnish (I know Watco does and I assume Minwax does as well). You can take a chance with those but you would be better off apparently with Boiled Linseed Oil. That's what AR used originally, so no hesitation there. Or, just wax over the RAF.

Kent

[RoyC]

Afterward you can use either Howard Feed n Wax or a coat of Watco Danish Oil (also available in a few shades). Again, easy to use: Wipe on/wipe off. Do not use any kind of polyurethane or varnish. Another nice finish is Minwax

Larry Lagace ("Vintage AR") confirmed to me that Watco Danish Oil will not work over Howards Restor-A-Finish, and it was not wasy to completely remove RAF when he decided it was not sufficient for his purposes. Larry has refinished a number of cabinets for customers who previously tried to get away with only Howard's RAF. Howards is a good way to spuce up a fading finish, but it is not a substitute for careful sanding and refinishing when significant scratches are present. I sometimes wipe it on and off a faded or previously refinished cabinet to spruce it up a bit. I never use it as part of the refinishing process after sanding, or as a treatment prior to using another finishing varnish or oil product.

Roy

[Carlspeak]

I believe Howards Restor-a-Finish has oil in it. No need to put more oil on top of it. When I use Howards RAF, I follow up with Feed-n-Wax.

[JKent]

Holy Cow! A controversy! (please don't send us to the kitchen)

Here's all I'm saying: When speakers are looking kind of sad, like the ones in Post #13, and there's no physical damage (chips etc) I personally do not like to sand them. AR veneer is thick compared to what they make today, but it's still thin and one slip could be disastrous.

When I refinish KLH radios (and I do a LOT of them), those with solid walnut cabinets get sanded down to raw wood and refinished with Minwax Antique Oil. The veneered ones are a different matter. On those I use Restor-A-Finish. But on the radios at least, RAF can leave them looking rather dull. I like to use several coats of Antique Oil and it has worked out well. YMMV.

Most of the AR and KLH speakers we focus on originally had an oiled walnut finish. That's walnut rubbed with boiled (not raw) linseed oil. AR and KLH recommended re-applying it every so often. IMHO, once you clean up a stained or dirty finish using RAF, something else should be used. I do not think RAF is sufficient. Howard recommends using their Feed-n-Wax. Following the manufacturer's instructions is undoubtedly a good idea. I have used Watco Oil with no ill effects but cannot recommend it, since the manufacturer said it's not recommended. However, they did say it was OK to used boiled Linseed Oil. And since that's what AR and KLH originally used, my thinking is the BLO would be a fine choice.

Decide for yourself. I don't personally like the way the wood looks with just RAF and I want to protect it. I suppose that's what the wax is for.

If you look at this tread http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6565#entry94977 post #2 shows some AR-91s in generally good shape but there's a flower pot ring on top on one and the finish is kind of dull and lifeless. Post #16 shows the after shots. These were treated with RAF, finished off with Antique Oil. I wanted a semi-gloss finish and it worked perfectly. If it's too glossy a little buffing with 0000 steel wool will tone it down.

As I said--YMMV. This is just what I do.

Kent

edit (5 years later): Please disregard the radio refinishing comments in the 3rd paragraph. I have learned that KLH Model Eights were lacquered so now after sanding the solid walnut I use Minwax spray lacquer. The veneer cabinets can be stripped with lacquer thinner, sanded VERY lightly and then sprayed like the solid ones.

[RoyC]

You really don't need RAF to clean up a stained or dirty finish IF you intend the final finish to be some other oil, varnish, lacquer, etc. Ordinary mineral spirits applied in the same manner as RAF can often be used as a cleaning agent without concern for incompatability with the final finish. It is also less expensive.

Roy

[ra.ra]

I want to say that Vern makes a valuable comment in post 15 about the use of steel wool. Steel wool is a great product, but not so much when factors of potential rust or magnets are involved. For speaker work, I strongly advocate the use of bronze wool, which has similar abrasive qualities but none of the magnetic ones. Bronze wool has long been preferred by maintainers of marine equipment, in order to avoid the potential rust from steel wool fragments, but a similar case can be made for bronze wool when it is used to avoid the strong magnetic attraction of speaker drivers. I have learned the hard way - - even when using brushes and opposing magnets to try to remove steel wool particles that get sucked in by a driver's magnetic field, it is difficult to eliminate all of the small particulate.

http://www.steelwool.biz/Bronze_Wool.htm\

With regards to cabinet re-finishing, many good points have been made here, but I do not believe there is any single authoritarian source on this matter. The Howard's products, which I learned about from this site, are indeed terrific, yet I have equivalent faith in Watco and Minwax products and the use of linseed oil, boiled or otherwise. Roy makes a good point about the multi-effectiveness of mineral spirits, as does Carl about Feed'n'Wax and JKent about Minwax. I believe that all of these products can be very successful in restoring the veneer finish on AR speaker cabinets, but I think that a most important prudent measure is to allow each step of finish application to sufficiently off-gas or cure before commencing with the next step.

[Chebu70]

Wow, wish I would have read the follow on posts sooner as i missed some great cabinet restoration tech! I hope my dried out old cabinets didn't give any one nightmares but did want to give everyone some assurance that the ar-5's didn't end up in an abusive home... See attached pics before and after the makeover.

Unfortunately i didnt see the posts in time and I had already skipped ahead to the howards wax and feed but happy with the initial results. It's been over a week now and the dry spots haven't reappeared but it'll keep a eye in things and revert to the RAF before reapplying the wax and feed.

Thanks again for everyone's expertise getting these old beauties singing again.

- Sean

State College, Pa

[Chebu70]

Sorry for repeat post.... Not sure how that happened. using ipad seems a little clunky, is there a forumapp that works with CSP?

Wow, wish I would have read the follow on posts sooner as i missed some great cabinet restoration tech! I hope my dried outsold cabinets didn't give no one nightmares but did want to give everyone some assurance that the ar-5's didn't end up in an abusive home... See attached pics before and after the makeover.

[JKent]

They look terrific Sean!

So after all the "controversy" what did you do to breathe life into those cabinets?

Don't think you can delete your post but PM GeneK or Carlspeak and ask them to delete post #23

Kent

[Chebu70]

Im happy with them! I pretty much just followed the directions on the wax and feed. Nothing special except on the initial application I let them sit for an hour or more before wiping off.