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AR-6 Restoration


Gabriel

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Yes, too many speakers!   I have some JBLs I'm using as rear speakers on the 7.1 sound system on the TV.

I oiled the AR-6s up last night.  They do look good.

The KEFs were bought many years ago (in the 70s, I think) and do lack in HF response in comparison with later speakers.

I rarely sit down to listen to music these days so I don't need what I have in speakers nor amps (Harmon Kardon 630 Stereo Receiver, Pioneer A717 amp, Sony STR-DE697, Sony STR-DE525), turntables (APAN BFU121, Pioneer PL51 direct drive, Thorens TD125 with SME arm and V15), then there are the Sony MD and CD players and Harmon Kardon HK1000 cassette decks.  I really need to sell instead of hoarding although I have a 7.1 sound on the TV as well as my hifi setup in the lounge room (separate systems).

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  • 7 months later...
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Hi guys,

some really great information in this thread, thanks to all who have contributed

I've recently acquired some AR-6s (pics below) that haven't been kept in the best condition but im working on restoring them. I'm no audiophile and do not have access to a lot of electronics equipment e.g. might just be able to scrounge a soldering iron from a friend. Sadly when I tested out the speakers, they sound really muffled as if the tweeters are not working at all. The foam is completely degraded and I will be replacing this, however the sound was so off I think there must be something else off. The pots are completely crunchy to turn and from the information in this thread I believe they may be the culprit for the lack of tweeter noise, first I'll try opening them up and cleaning but possibly completely replacing them.

First question is, when prepping for a refoam, when clearing away the 'outer ring' of old junk should I be scraping all the way down to the metal? I started scraping and then came across some sort of hard woody material and then panicked and stopped, also pic included.

Secondly is the pots cleaning/ replacing route the most best angle of attack for fixing the muffled sound or should I be looking elsewhere, from what I've seen most of you are confident in the performance of the compulytic cap so I will not be bothering to replace that.

Please also let me know anything r.e the history/ originality of any of the parts in the pictures

 

cheers

 

 

certificatecomp.jpg

bothcomp.jpg

circuitcomp.jpg

opencomp.jpg

closedcomp.jpg

refoamcomp.jpg

woofer bottomcomp.jpg

woofer sidecomp.jpg

woofer2comp.jpg

woofer3comp.jpg

backcomp.jpg

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Do not scrape off that mystery ring that you've uncovered - - it is essential for a proper foam installation. You have a very nice (and unique!) pair of Euro-assembled AR-6's. Will comment further as time avails - - am on the run again today.

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Hi, yossaray, and in addition to JKent, I'll offer a second welcome to you to this forum.

Not sure where you are located, but the European origin of your speakers is suggested by several clues: the printed labels (duh!); the slimline profile at cabinet perimeter; the multi-color fiberfill stuffing; and the painted cabinet backsides. Those speakers are fully restorable and deserve the necessary attention, but there is one thing that stands out with your pair.

I cannot recall ever seeing this before, but your particular pair seems to combine equal aspects of commonly known versions AR-6 ver. A and AR-6 ver. B. All of the in-box crossover components are clearly version A, but that specific woofer and its attached capacitor (24uF?) and resistor (10 ohm?) are unique to version B. Your hybrids have seven components in each crossover circuit: two coils, two caps, two resistors, and one potentiometer. I would suspect that once restored, these speakers will indeed sound terrific, but this evidence seems to confirm that the piggyback cap and resistor accompany this particular woofer wherever it travels, and I think it has only been found in the AR-6. 

About that woofer ring. If you look closely, you'll see that a similar ring is present under the spider - see pic attached. The lower spider ring is durable hardboard, but the upper basket ring is more like a compressed cardboard that can be easily damaged. If this does happen, just build up the surface again with glue or epoxy or any compound that can be sanded smooth prior to foam install. The added dimension that this ring provides enables the woofer to reach its outermost extension and thereby maximize its LF capabilities. Also attached is before-after pic of my pair of ver. B AR-6 speakers, which use the same woofer as yours. It is worth the effort to restore these, and the work and results will be satisfying.    

 

AR-6 schematics A and B.jpg

woofer rings.jpg

before:after.jpg

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thank you so much for all the information, how would you best recommend removing the ex foam gunk from the outside ring without damaging it? light sanding?

and do you think a simple potentiometer clean up could get the tweeters working again or is there a possibility the tweeters (or another component) is broken/ in need of cleaning or replacing

ra.ra how did you get your black surrounds looking so smooth and clean, did you respray them?

thanks again

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On 6/13/2019 at 2:11 PM, yossaray said:

..how would you best recommend....

Hi yossaray, I'm not sure I know exactly what you're asking, but here's some additional thoughts. Also, I've done at least one other restoration of AR-6's using this same woofer, so let me know if you need additional pics. I'm including a couple pics from the most recent restoration.

For removing the foam residue on the outer ring, I probably used a combination of this chisel-shaped knife blade (lower one) and some light abrasive paper. Just work slowly and carefully so as not to damage.  Same for the outer rim of the paper cone - - no blades probably required here but this residue can be cleaned mostly with fingers and maybe light sandpaper. You want clean surfaces for all new foam glue lines. 

About those tweeters, they "look" to be in fine shape but first you'll need to determine if they are functional. Assuming they are, then you've got the decision about the pots. You can disassemble and inspect, and then decide whether to try to clean and restore the pots or as JKent has suggested, replace with new, inexpensive L-pads. Just my opinion, but I find this particular pot-crossover particularly difficult to work with. This is mostly because of the coil wire and the very stiff short nichrome wire (resistor) soldered to the pot lugs, but also because you're trying to work inside a tight 8-inch woofer hole.  

About the "black", are you just referring to the front panels of the cabinets? 

x-acto blades.jpg

woofer clean-up.jpg

driver detail 3.jpg

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  • 1 year later...

An update on the speakers I posted here a year ago:

I finally got round to restoring them, in total I:

Refoamed the woofers

Sanded, cleaned and applied Danish oil to the cabinet veneers

Used a bleach and water mixture to get stains out of the linen grilles

Polished the badges with brasso

Sanded and lubed the contacts of the potentiometers (with wd40, not what would be recommended however it was the only thing I had on hand). I was able to lightly sand the potentiometer contacts without desoldering it (as I had read on this forum how fiddly the stiff nichrome wire can be to resolder and I am not an experienced solderer) by carefully taking it apart in place by removing the clamping pin. Before I did this one of the speakers produced no sound from the tweeters because of the corrosion however after this the potentiometers are almost perfect on both.

I also suffered a t-nut blowout which I epoxied back in with some supporting plywood underneath, hopefully this will hold.

I wasn't able to fully able to remove some water stains from the cabinet veneers I may try again in the future, any tips would be very helpful.IMG_20200829_134025.thumb.jpg.5fa40f05e2f9b093e2974ec3b8ae2e94.jpgIMG_20200829_134036.thumb.jpg.0a08df5002e5d93d661376d5156ef918.jpg

I have a question regarding what is referred to as the slimline cabinet perimeter, I sanded and cleaned with white spirits the bottom of one of the sides and underneath is a light coloured piece of solid wood as shown in the picture below. I tried applying a dark oak coloured Danish oil but it remains very light. Originally I think they were either painted or a heavy stain was used. Anyway any advice on how to treat these would be great.

IMG_20200829_134652.thumb.jpg.e02d208c4f6d2922e56f7b377ea53eea.jpg

Thanks to jkent and ra.ra's help and advice in restoring these, they sound fantastic!

IMG_20200904_143447.thumb.jpg.1d4951b44235a7026022df0d439fcb8f.jpgIMG_20200903_135253.thumb.jpg.ea671d29d3f8a7e1e2109e3989fe2890.jpg

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  • 10 months later...

Hello,

I hope someone is still looking here and can answer to a little strange question. I received a couple of AR6 and I'm trying to restore them. There is no woofer, but I can found something very similar to original. The problem is On the back of the boc there is a paper indicating a 8 OHM of impedence. And I remember it was right , but the tweetters are 4 OHM  . Nobody replaced it they are original. How it is possible ? what should I buy   8 Ohm or a 4Ohm woofers ? Thanks in advance for yr courtesy.

Giandiego.

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1 hour ago, Giandiego said:

the tweetters are 4 OHM  . Nobody replaced it they are original. How it is possible ? what should I buy   8 Ohm or a 4Ohm woofers ?

I have never worked on the AR-6 but it is not unheard of for an 8 Ohm system to have a 4 Ohm tweeter. Try to find 8 inch 8 Ohm AR woofers.

Kent

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The measured resistance (dcr) of an individual driver is simply a resistance reading at a specific frequency, and can be much lower than the "rated impedance" of a speaker system. The impedance of the system is an estimate of the average resistance relative to its overall frequency response. For example, the tweeter of the "4 ohm" AR-3 has a DCR of under 2 ohms.

The crossover often has more to do with the "impedance" of a system than the individual drivers.

Roy

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  • 1 year later...

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