Early AR6's

[ReggaeBen]

Hi everyone,

These sweet looking 6's have become available for me to buy, they are early model from telling of the pot on the rear and what looks like maybe Alnico woofers? 

Planning on going ahead if these may be considered a bit special.

Look forward to hearing some comments.

Ben 

 

 

 

 

[ra.ra]

Hi Ben. The AR-6 is a fantastic small loudspeaker, and from the pics and your description, those appear to be fully original and in great shape all around - - grilles, badges, and Euro-style cabinets, etc. The front-wired tweeters appear unblemished, and even the woofer foams look like they might be intact. 

I think you may be right about the woofer magnet - - those appear identical to the one shown here from a pair of early AR-6's from 1971. These have a huge alnico slug magnet and a voice coil movement of almost 3/4 inch. You might want to check the tweeters to be functional, but these look terrific and might be a very easy 'restoration' project. Keep us posted. 

[Phxjohn]

I have a pair of early 6's in addition to a pair of 3a's. The early 6's used a unique woofer(for a short time) that had the magnets surrounding the voice coil for longer throws and deeper bass. The woofer circuit also had an inductor on it. I use the 6's with a Marantz 5005 integrated amp, Garrard Lab 80 with GE VR 1000 cartridge. 

[ra.ra]

13 hours ago, Phxjohn said:

The early 6's used a unique woofer (for a short time) that had the magnets surrounding the voice coil for longer throws...

These pics of the long-throw alnico AR-6 woofer show movement in the range of 3/4" overall.

 

[Phxjohn]

Impressive !

[ReggaeBen]

Good news is that I bought them today, will have them arrive within the week.  I'll enjoy comparing these to my other pair of 6's with the ferrite woofer, I assume these alnico ones might sound smoother.  Stay tuned 

[Pete B]

On 6/20/2018 at 11:21 AM, ra.ra said:

These pics of the long-throw alnico AR-6 woofer show movement in the range of 3/4" overall.

 

That is a great picture, where do you find these things, or did you take it?

Nice demonstration of voice coil overhang the center picture is at rest I take it?

Is the top plate .25", then if the center pic is at rest the overhang looks about equal to the top plate,

perhaps slightly less from the gravity pulling the cone down?  If that is all correct then it would have

a .75" voice coil wind length and an Xmax of .25" peak, or .5" peak to peak.  Xmech of nearly .75 pp

as you stated.

[ra.ra]

6 hours ago, ReggaeBen said:

I'll enjoy comparing these to my other pair of 6's with the ferrite woofer....

Congrats, that is a terrific looking pair of AR-6's, so we''ll be interested to see more pics and descriptions of the drivers, crossovers, and cabinets. With the ribbed cones, I assume those might have the alnico woofers we've discussed here, but I guess you won't know for sure until you pull them out for examination. Please tell us more about this pair as well as the other pair you have when you get more information (pics!), and are you in the EU or the UK or the USA? I think your first test song on these speakers should be a Bob Marley number.

2 hours ago, Pete B said:

That is a great picture, where do you find these things, or did you take it?

Thanks, Pete, I think the image describes this characteristic rather well, and yes, the middle pic shows woofer at rest. This is a composite pic I made of my own early AR-6 woofer (s/n's below 04000), and I just use a little pocket digital camera and then compose, crop, manipulate, and assemble a multi-image using some very basic image software that comes on most Mac computers. Lastly, I adjust the contrast and sharpness and save a jpeg file usually no larger than 100KB for use on this site.

Credit where it's deserved - - I constructed my own image after seeing this info from a 1972 review I found online from a British publication. The review goes on to say that the AR-6 represents AR's best-ever value; it is the best true bookshelf speaker they had ever tested; and that AR is rumored to be establishing offices in the UK.

I just noticed for the first time that these markings on the cone backside are identical to those shown on my woofer above.  

[Pete B]

I'm wondering what is the correct dimension for voice coil exposure at rest for an AR-2ax woofer,

anyone know?  That is a good way to check if the VC rest position is correct.

[ReggaeBen]

Hi guys,

Update here on the 6's.  When they arrived I found that the the cabs had repairs to some small dings and a dark oil added, nice job.  Either in transit or something went wrong when the last person had them open,  I noticed a t nut that had gotten loose and ended up inside the driver, both cabs too! They'd been refoamed with the inner lip of foam glued to the bottom of the cone, guess it's going to make cleaning and preparing for refoam trickier.  So I played them, yes I felt a good Bob Marley track fitting for this!, no issues other than scratchy pots and perhaps an aged sound, like meaning they would improve after a thorough go over and recap.. 

 

So far just working on the first speaker.

The tweeter cone has been pushed in and slightly torn so I applied a very small amount of speaker glue to "weld" up the gap.  Then came cleaning the pot, actually not bad and cleaned up fine along with a steady ohm reading.

My cap chosen here is a ltyhic from P.E @ 10 uf that I've bypassed with a Russian silver mica at .01 uf, never tried this combo so hopefully this will sound sweet and natural.  The original paper/wax cap tesed a little over at 30uf ?  

Now will be my first refoam on the 8" woofer, got the bose type commonly used to be fitted, shimming as recommended.  

Question,  would anyone like to recommend me to bypass the inductors and run the woofer at full range? Or tell me to stop trying to "better" the design and leave as is.  And what could I use to apply on the woffer tinsel leads to slow oxidization?

Cheers

Ben 

 

 

 

[ra.ra]

On 7/27/2018 at 10:00 PM, ReggaeBen said:

I noticed a t nut that had gotten loose and ended up inside the driver, both cabs too!

It can be a real nuisance when these T-nuts become loose, but at least yours was easily retrievable. Try to straighten out any bent prongs, and then re-insert with a dab of epoxy on the outer shaft - - do not get any on the inner threads! Also, a good idea to smear a dab over the backside flange of the other T-nuts while you've got them open.

About the woofers, attached is pic of my same woofer after re-foam with Bose-type surround. If you look closely, you can see that the dust cap was sliced for shimming and then carefully replaced in same position and touched-up with tinted glue. It appears that your dust cap has been sliced in a "V" configuration near the lead wires - - any idea about this?  On your tinsel leads, it's difficult to see any corrosion, but I suspect these wires are sufficiently robust to withstand a little surface discoloration with no ill effect. 

On the tweeter, those dented and dimpled caps are annoying, too, and it looks like you've probably repaired it adequately.

I would suspect that the 10uF P.E. electrolytic cap will work just fine, but I can make no comment about the additional bypass cap. Regarding your cap measurement, a reading of 30uF sounds a bit abnormal - - are you certain that the cap was completely removed from circuit? And how did the other one measure?

For me, the most difficult thing about working on these crossovers is working around that short and very stiff nichrome wire between the pot terminal and the tweeter lug. IMO, it makes for a very tedious dis-assembly process. 

[ReggaeBen]

Good advice here ra.ra, I did happen to re-straighten the prongs and added an adhesive so next time the cabs are open I'll do the backs of the other flanges also.  I was curious too as to the V cut on the dust cap and thought the last person who refoamed then may have done this,  that was until I saw a photo of another pair recently with the same V in around the lead wires.. seems like a production thing but not sure yet why? 

Yeah I was taken by the high reading, the other was aprox 25uf, both out of circuit.  The  new P.E npe measured 11uf and I also matched the esr (with bypass added) to .31 ohm. This has improved their output and sound nicely, I decided to leave trying to pull the dimples out for another day.  There is a slight rattle noise from one tweeter when played at higher volume, I'll do some detective listening with the stethoscope and generally not push them hard as I imagine this could be an age related issue.  I'm still getting to know these speakers and to some degree the caps may not be broken in yet, they have a quite laid back mellow sound that goes deep in the bass, which is awesome for my dub Lp's! My tuner is locked on a classic station and they shine here too so I'm pretty pleased with the outcome.

Couple of other things to mention, the fibreglass fill weight were both 16oz per cab.  The tape covering the VC on the woofers was coming away in places so I figured it best to reglue it back down. The design would want air only to come via the spider and if it were leaking in around the tape I'd imagine a slight change in frequency not desired and also an entry for debris.  I'll get a couple of pics up soon as I also cleaned up the badges to good effect.

Now looking forward to working on my other pair of 6's as learning from these, they're in line after the 5's.....

Ben