AR18J Restoration - information and help

[sudhir]

Hello All,

My Name is Sudhir and I write from India. I am very happy to have found this forum of great know how and people with expert knowledge of these wonderful speakers.

I have owned a few AR's in India. These are quite a rarity in this country and I have been relentlessly searching to get my hands on more of these speakers.

I have a AR18J, the TSW210 and the TSW510 (Dads). Of all these the AR18's are my favorite. I bought them from a guy 15 years ago for some 15$. At that point one of the speaker was not working . A quick inspection revealed that one of the lugs had come off at the woofer. These little speakers have been paired with a Rotel RA - 414 for the last 15 years and have been with a friend when I left the country and are back with me now.

Now the 18s were not in the best shape when I got them , but have always sounded nice and rounded. The woofer material seemed to have been replaced locally and I have been searching for a replacement original on ebay for a while and nothing seems to turn up. I see a lot of replacements for the B and BX suffix models , but none for the J suffix.

The aim is to return the speakers cosmetically to the condition they were when new.

1. I am willing to CNC the box to exact specs and use the old front baffle as I love the typography on them!
2. Recap the speakers
3. Silver internal wire
4. Use new / refurbish connectors on the rear.
5. I know i will not get the original veneer colour, but will substitute with something very close.

 

Here are some pictures of the speakers and the listening setup. I know i have placed the speakers horizontally, but will have them back vertical as soon as I get the stands shortened! 

 

Picture

1: How it looks from the front

2: The typography and front baffle

3. Crossover : Everything seems to original

4. The fill seems to have been added at a later stage. See the colour difference?

5. Woofer front

6 , 7 and 8: Rear of woofer (Seems to be original)

9 and 10. Cabinet disintegration as I moved them around for the pictures!

11 and 12. The original foam grilles in a very delicate shape.

13 and 14 . My listening setup!

 Experts! Waiting for your suggestions!!!!!

Thanks and Regards,

Sudhir

 

 

[ra.ra]

Hi Sudhir, and welcome to the forum. The speaker model you have is the original AR-18, which later morphed into the AR-18s and then the AR-18b. The "J" that you have noted is part of AR's catalog referencing and requires little attention on your part - - just disregard this designation. It is also interesting to note that the AR-18 used a single serial number (in your case, 062207) for both speakers which were sold as a pair.  

The AR-18 is a terrific speaker that has developed sort of a cult status in parts of Europe as a near-field professional studio monitor, and your speakers look pretty good. The flaking cabinet can probably be repaired with some liquid epoxy and it is rare to find the original foam grilles in such good condition. I think all of your stuffing is original.

While it is always depressing to find these tweeter dust caps dented, this generally has no adverse effect on performance. And it is probably a very good idea to replace that original black/red cap - - I think it is 6uF. The woofer presents a couple of small mysteries, however. The 200001 part number is the correct driver, but that light grey ribbed cone does not look original to me. And, of course, the mirror reflective outer dust cap is not original, but it could have been a simple replacement when the woofers were re-foamed at some point. It is also interesting to note that this woofer originally had two dust caps: inner (flat) and cosmetic outer (domed).

[sudhir]

Thanks you for the reply Ra.Ra. That was a lot of information and trivia I was unaware of!

Yes the capacitor is a 6uF. What kind would you suggest replacing it with? 

Any suggestions for the internal wires?

So i managed to track down a guy who has another pair in India but with a EJ Suffix. So I guess they are identical to what I have. They are not in the best of shape, but I am interested in the woofers and spare tweeters. He is asking 12,000 rupees (185 USD). I know it sounds like a lot, but the Indian prices as a thumb rule are twice US eaby price plus a little more.

I am attaching a few pictures from the seller. Will have a look at them in a week and give him a token deposit.

Probably will make a custom cabinet with a decoupled tweeter with the white woofer and spare tweeters for the bedroom. :-))))

[ra.ra]

That second pair looks fine, too, and even more fully original than your current pair. Tweeters don't look badly beaten up, and the woofers appear to have a decent re-foam job. Having both pairs, it would be a fun project to mix and match drivers and cabinets to put together a "Better" pair for Living Room and a "Good" pair for bedroom. I think all of the cabinets can be salvaged - - no need to build new ones - - the glue drips can be cleaned up and the cabinet flaking can be reinforced and re-painted. 

Am not sure what type of parts suppliers you have access to in India, but I'm sure you can locate a reputable source of audio grade components. For the 6uF caps, either a good quality non-polar electrolytic (NPE) or an inexpensive film cap (metalized polyester or polypropylene?) will work just fine. Sometimes the 6uF value is difficult to find, but you can always parallel two caps to create the 6uF value (example: 3uF + 3uF; or 3.3uF + 2.7uF) 

Maybe you try one type of cap in one pair and a second type of cap for the other pair, and then compare results? Your black caps are probably rated at 50 volts, but most new caps will have higher voltage ratings - - this is normal - - and new caps rated for 100 or 250 volts should present many good options. Generally speaking, as voltage increases, physical dimensions increase as well and so does cost. Translate these estimates as you'd like, but buying replacement 6uF caps here in the U.S., I'd pay no more than $2 or $3 apiece and have a wide selection available. 

While there is nothing particularly impressive about the original internal wiring (I think it is 18 ga?), it is good quality and there will most likely be no perceptible performance improvement by replacing it with something more exotic.

[djcheung]

This is my pair of the 18.

[sudhir]

 

@ra.ra Thank you for your inputs. I will go have a look at the other pair coming week and pick them up. My cabinets look much better in the picture than in real life!

I will work on new wiring for the speaker internals. Will keep the nut type connector and get rid of the 0/-3db switch on the rear. Will bypass it but keep it to complete the authenticity! 

Any good source in the USA for the capacitors? Girlfriends friend is coming in a month and I can have her bring them when she comes. Maybe some good wire for the internals?

@djcheung your set looks so good! Is the speaker on the right (the one sideways ) the rear of the other speaker? Did you re vinyl your speakers?

 

The originals have a black "ring" around the woofer to cover up the excess metal. What material is that. Any alternatives and substitutes?

Regards,

Sudhir

[michiganpat]

it's an open cell foam .  I've made some out of felt on mine, and have also cut out foam rings....

[sudhir]

7 hours ago, michiganpat said:

it's an open cell foam .  I've made some out of felt on mine, and have also cut out foam rings....

@michiganpat Thanks for the quick reply. I am not able to get any source online in India for the foam mentioned. Would you be kind enough to point me to your source in the US? Wouldn't mind ordering it online and having it shipped to my friend who will be coming to India in a month. And what kind of cutting technique do you use to get a good end finish?

[ra.ra]

On 11/4/2017 at 9:51 AM, sudhir said:

...and get rid of the 0/-3db switch on the rear.

Am curious why you plan to abandon the switch?

This is a simple, inexpensive, soft material that I've used with success for the gasket seal between metal basket and cabinet. It would work fine for outer trim rings, too, if desired. First pic shows process of cutting foam sheet, and second pic shows an example of what I often tend to do - - just paint most of the exposed basket metal prior to applying new foam surround. 

http://www.michaels.com/12x18-foam-sheet-by-creatology/10290391.html#q=foam+sheet&pmpt=qualifying&sz=24&start=12

Re: capacitors, attached are three links for good quality common crossover caps (6.2uF is OK, too).  

https://www.parts-express.com/dayton-audio-dmpc-62-62uf-250v-polypropylene-capacitor--027-427

https://www.parts-express.com/solen-62uf-400v-polypropylene-capacitor--027-558

https://www.madisoundspeakerstore.com/carli-capacitors/carli-mylar-6-mfd/

On 11/3/2017 at 6:57 AM, djcheung said:

This is my pair of the 18.

That pair looks terrific - - it looks like those cabinets are real wood veneer?

[djcheung]

Hi Sudhir,

I can't really remember what model that speaker was !

I didn't have to redo the veneers.

I think it is something to do with the humidity over here being reasonably constant so most of the speakers I have seen are in good conditions.

I will try to find out what that speaker was.

The one that AR18 is sitting on I think is the AR14.

[sudhir]

On 11/5/2017 at 10:51 PM, ra.ra said:

Am curious why you plan to abandon the switch?

@ra.ra I am just being paranoid about the corrosion in the switch after being in a equatorial humid weather for so long.

I though I might have some improvement by bypassing the switch and resistance.

I also just realized the resistance is in parallel and when in the switch is in "off" / "0" position position , has no effect on the quality unlike the capacitor which is in series! (I hope I am right!! :-) ) 

On 11/5/2017 at 10:51 PM, ra.ra said:

 

This is a simple, inexpensive, soft material that I've used with success for the gasket seal between metal basket and cabinet. It would work fine for outer trim rings, too, if desired. First pic shows process of cutting foam sheet, and second pic shows an example of what I often tend to do - - just paint most of the exposed basket metal prior to applying new foam surround. 

Hmm. I think I have seen something very similar in hobby shops! Let me see if I can find them locally.

 

Which now leaves us with the usual debate about the capacitors!  Mylar Vs Polypropylene! 

As this is my first rebuild and have no experience with electronics, I will again wait for your advice on the kind of capacitors! I am willing to go upto 10$ each for them! 

Regards,

Sudhir

 

[JKent]

As I understand it Mylar will have ESR closer to the original electrolytic. I use Mylar often but in the long run I doubt it matters much. YMMV

Kent

[ra.ra]

3 hours ago, sudhir said:

....the resistance is in parallel....

Although we cannot see all of the wiring in your AR-18 crossover (regarding phasing of drivers), I believe the AR-18 crossover is essentially identical to the AR-7 which preceded the 18. I see no reason to eliminate the switch - - of course that's up to you - - but you can see from this schematic that the switch merely includes or passes by the 3 ohms of resistance to offer two different levels of tweeter output. When switched accordingly, the resistance is in series with the tweeter.

3 hours ago, sudhir said:

.....capacitors....is my first rebuild ... I will again wait for your advice

 Again, this is your decision, and I'm fairly certain that from India you can locate some very good Asian or European made brands from reputable distributors. Since this is your first rebuild project and you'll be doing two pairs of speakers, why not get two or three pairs of modest-cost caps (no more than a few dollars each) and see for yourself if there are differences and what you end up liking best.   

[Starquest]

These are nice speakers.  My uncle had a pair of small ARs, similar to these.

Is there an AR model of this vintage that is smaller?  Or is this the smallest one?

[Stimpy]

1 hour ago, Starquest said:

These are nice speakers.  My uncle had a pair of small ARs, similar to these.

Is there an AR model of this vintage that is smaller?  Or is this the smallest one?

There was an AR-8B, that used a 6.5" woofer.  Maybe that was it?

 

[ra.ra]

16 hours ago, Stimpy said:

Maybe that was it?

AR-8B.....Good call, Stimpy, or maybe it was this one - - the AR-8S, an even more rare and perhaps Euro -only model. 

[Stimpy]

2 hours ago, ra.ra said:

AR-8B.....Good call, Stimpy, or maybe it was this one - - the AR-8S, an even more rare and perhaps Euro -only model. 

Ooh, I like those better.  They look more like my AR58s speakers.  It's a shame that more of the European styled speakers weren't available here?  Or were they?  I'm definitely no expert.  Plus, those make me wonder how the 58s models would look with the AR91 woofer trim rings? 

[ra.ra]

4 hours ago, Stimpy said:

Ooh, I like those better. 

Yeah, I'd love to find a pair of these rare little beauties. Because of the tiny cabinet, I had assumed that the 8s also had a 6" woofer like the 8b, but according to this thread where I first encountered this model, the drivers are the same as the AR-18s, including the 8" woofer.

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/4458-ar8s-or-ar8se-refurb/

 

[sudhir]

Hello All, Just wanted to update you on the progress! Had a friend bring these back from the US. And now to solder them. I got a few extra just in case!

Now I have never soldered before. But it doesn't seem to be too much of a job considering these are big components. Will keep you posted on the progress! 

Regards,

Sudhir

[sudhir]

Hello All, Finally plucked up the courage to change the capacitor.

@ra.ra @JKent

Quick question before i do this. Will bypassing a 40 year old yield a clearer signal path?  I never had the need to use the -3db switch. Maybe my ears top end is rolled off! 

[dxho]

It should yield a clearer sound, yes. Those black/red caps in particular
can be WAY out of tolerance.

[ra.ra]

Hello sudhir - - I've been away for some time due to several unexpected events, but it looks like you are inching towards positive progress. The Carli and Solen caps you've acquired are suitable choices, and dxho is correct to suggest for you to abandon those aged red/black caps.

Regarding the switch component, ultimately this will be your decision. I have experienced AR speakers from this vintage where a 3dB switch had minimal, if any, perceptible effect, but I have never felt the need to stray from the original design and bypass, or essentially eliminate, a tweeter control. It's effectiveness might not be perceived in your particular room environment, but that does not mean that it might be an important component when properly engaged in a room with different acoustical properties. I would recommend to keep the switch and just replace the cap with the one that you prefer.

[jayrosc]

Reading this thread has convinced me to re cap my set of AR17's. I got them a couple months ago, re foamed and have been using them in my office. Rather than pull a woofer and tear out the filler to check, does anyone know if the cap value on the 17's are the same as on the 18's? When I first got these I recall reading, perhaps on this site, that they were same, but I could be wrong.

[jayrosc]

Answered my own question...I remembered I took a pic of the cap. Now that I've seen the ones here I knew what to look for....yup....6uf!

[jayrosc]

Yikes,,,this might be just too easy!!! I found some Solen's I had here....a 6uf and two 3uf's. My only question is do I need to just twist the wires together on the pair of threes, as in side by each other? Or do I need to set them up one after the other, like links in a chain?