What do you think? AR-6

[Mario]

I have just finish to restore a pair of AR-6.

Very good shape and they look just new.

The sound is warm and the high are too smooth, tweeter work well but for a correct listen I must turn at max the increase hf level control and turn at max the high controll of NAD 3020 amplifier.

Do you think clear the level control and change the capacitors on the x-over can resolve the problem? Or this is just the sound of AR-6 ?

Another idea that I have, is to replace the tweeter with the mid and tw of the AR-3a and so transform this AR-6 in a small AR-3a, What do you think about this kind of tweak?

Thanks,

Mario

[Tetrode]

I would replace the crossover capacitor first.

They are way past their life expectancy and is very likely out of specification.

[JKent]

I would replace the crossover capacitor first. They are way past their life expectancy and is very likely out of specification.

I agree, but also clean the pot or replace it with an L-pad.

Nice job on the speakers!

Kent

[ra.ra]

Hi Mario:

I would agree with Tetrode that as a first measure, the capacitors most likely require replacement. Attached is a photo (not mine) of an AR-6 crossover with capacitors newly replaced. I assume that the two black cans are 4 uf and 6 uf capacitors - they appear to be Solens. The second order of business would be to remove, clean and replace the tweeter pots to re-establish their variable control.

Those are beautiful speakers - - - the cabinets, grilles and drivers are all in great condition. They also seem to be a mildly unusual hybrid - - - while they have the thin front edge Euro profile, the tag on the back lists neither the Netherlands or England manufacturing address. Also, it is far more typical for the Euro versions to have the three position switch rather than the variable rheostat that yours have. Further, the Euro versions more normally have rear-wired tweeters, while yours have the front wires. Like many AR speaker products, there are many different permutations of the same basic speaker design, and what you seem to have is a fully typical U.S. version but with the Euro cabinet profile.

Not a good idea to try to create the baby AR-3a. The AR-3a is a 4 ohm speaker and the AR-6 is an 8 ohm speaker, plus the layout of front baffle board does not lend itself to accommodating a third driver.

[genek]

New caps may help, but probably not that much. Crossovers in classic era ARs were mostly sound shapers and the FR was primarily the result of the driver mix.. I use a pair of microstatic arrays on my 6's, mostly to widen the soundfield but they do increase treble as well.

If you want to try other options for the upper ranges, just remove the jumper from the back terminals. This will take the tweeter out of the circuit and allow you to use the woofer with other drivers without gutting the cabinet.

[RoyC]

Another idea that I have, is to replace the tweeter with the mid and tw of the AR-3a and so transform this AR-6 in a small AR-3a, What do you think about this kind of tweak?

Thanks,

Mario

Mario,

The 3a tweeter will not function properly in the AR-6. The crossover is much too low, and the result would not be remotely close to a "small AR-3a".

...better to follow the advice above, and go from there.

Roy

[ra.ra]

To Mario: All good advice, as RoyC has already noted. If my assumption is correct that these speakers might be slightly rare, there is an even more compelling argument to maintain them in their original state with nearly stock components, as far is is practicable. They already look great and with some minor work they should sound great, too. Carving up the cabinets sounds like an ill-advised move to me.

To genek: could you please elaborate on your "microstatic arrays"? I don't know what this means, how you do it, or why you do it. I am all eARs.

[genek]

Add-on tweeters to increase HF dispersion and levels.

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=3251

[Mario]

Hi All, thanks for your reply.

I have just finish to change the capacitor (this AR-6 have only one 10mf capacitors not a double cap like the ra.ra pic) and clear the pot. They are just a bit more clear in hf, but I think now AR-6 sound is tipical poor of hf.

In any case another good system for my collection of AR, I have the AR-3ai and AR-7, I have had also other version of the AR-6 with a more recent modern woofer but I was researching this old version I have now.

The idea to design a little 3a still remain, probably I will find the component midrange and tweeter and built a new cabinet. I will let you know.

[JKent]

Hi Mario

Here is a thread that discusses the different versions of the AR6:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=1687

You may find useful information there.

By the way--you cleaned the pots, but sometimes that does not fix them. Check them with an ohm meter if you have one and make sure you are getting good contact throughout the entire range.

Kent

[xpat]

Mario,

Very nice looking speakers!

I just completed an upgrade of my AR6 speakers. I put in new L-Pads and 1% tolerance caps and was extremely pleased with the result. I'm still amazed at how good these small speakers can sound. After upgrading, I noted the following:

• fine details I had never heard before on recordings I played many times before;
  
• Great depth, texture and clarity
  
• Substantial bass output that was tight - not sloppy
  
• Soprano vocals that were not harsh and piercing but smooth and elegant
  

The speakers do not have the gut rattling output of my AR5s, but come close. They are great speakers for their size.

In my opinion, the speakers have more than enough high frequency output. I agree with the majority of members who suggest changing the pots for L-Pads, and changing the caps. I think you will be very happy with the result.

Lastly, I also agree with many of the members that trying to make a baby AR3 is probably not a good idea. The crossover frequency for the AR6 is 1500 Hz. The crossover frequencies for the AR-3a are 575Hz and 5000 Hz. The AR6 is a classic and probably best left as designed.

Best of Luck!

XPAT

[xpat]

Mario and for other members who are interested, I'm attaching AR-6 Technical Data I picked up from a friend yesterday.

AR6 Technical Data pgs 1 & 2.PDF

AR6 Technical Data pgs 3 & 4.PDF

[ra.ra]

My interest in this thread is directly related to trying to learn about the various incarnations of AR-6's - - - I expect to also take ownership of a pair very soon, which I mentioned in a post I initiated several weeks ago.

http://www.classicsp...l=&fromsearch=1

I trust there has been sufficient commentary to dissuade Mario from cutting up these beautiful cabinets with extensive modifications, but most certainly, Mario demonstrates a designer/tinkerer/inventor spirit here that afflicts many who read and post here on CSP. By all means, Mario, try to build your own and see what you can do! Even though I am very loyal to my Acoustic Research products, the speaker that comes to my mind at the moment that most closely resembles a "baby 3a" might be the Rectilinear Mini-III (see pic attached). It is of similar vintage (early 70's, I think); it is deeper than, but otherwise very similar in dimensions to the AR-6; it is a 4-ohm 3-way speaker; and, it has a robust build and excellent finish appearance.

A couple comments in this thread surprise me a little bit. The first is genek's comment that new caps might not help that much with HF performance - - - this may in fact be the case, bit it sounds a bit at odds with most of what many other speaker aficionados advise and report. Second, it is surprising to hear that both genek and Mario are less than enamored with the performance of the AR-6 tweeter. I have read many statements on this site that go so far as to state that this tweet is among their all-time favorites produced by AR, so to hear of two owners who are disappointed in the tweeter performance is already tempering my (previously high) expectations somewhat.

To xpat, thanks for the tech data. This is the document that convinces me that all AR-6 woofers had foam surrounds, even tho' some early woofs had alnico magnets and most others had ceramic magnets. While there is certainly a strong group who advocate L-pads, I don't know if I would agree that it represents a majority. There is an equally strong voice which suggest repairing the original pots, if possible, and that is probably the route I intend to travel.

Your own upgrade sounds like it has very satisfying results for you - - - congrats. I find it interesting that you have the 5's and the 6's - - - sort of the black sheep of the classic line.

[genek]

"Disappointed" is really not the right description for my impression of the AR-6. It is simply a smaller speaker than the 2 and 3 series ARs, with less ambitious performance targets. I never expected to get anything more from it, and I would not have bothered to go out looking for additional treble had I not stumbled across the Microstatics at a swap meet.

[michiganpat]

ra.ra,

I too am surprised at the disappointment in the 6's tweet, as it is the same tweet (albeit rear-wired) in my AR18's, which are among my favorites....I don't find them overly dark or muted as it sounds like some have complained....they are actually the same tweet as what's in the AR7 as well.

if one were to try to "hot rod" by replacing the tweeter, I'd be looking at a 1" dome or so with a Fs in the 600hz range, like a number of seas tweets.....you'd probably have to mod the xover to at least a 2nd order on the tweeter side, though

[ra.ra]

Oops, I had not meant to mis-characterize your initial evaluation of the AR-6's or your subsequent modification intentions - - - perhaps I should have said ______ instead of "disappointed". So many of us are tinkerers and fixer-uppers, so I do understand your curiosity when the Microstatics introduced themselves to you. By the way, thanks for the earlier description - - - I did not know of these products at all. Hey, at least the AR-6 already had the three rear terminals so that this experiment was almost begging to be tried.

Most certainly, the AR-6 is smaller and less ambitious than the 2 and 3 series, but since this highly touted tweeter was designed and implemented (widely, in several models) more recently than any of the series 2 or 3 HF drivers, isn't it reasonable to expect that there would be improved (and ample) treble performance from this modest two-way product - - particularly one which was about to push the vaunted AR-4x off of its long held pedestal as "king of the small 2-way bookshelf" speaker?

Speaking of swap meets, I had the good fortune to attend the "MIT flea" yesterday. My understanding is that this event began many years (decades) ago as a meeting forum for ham radio enthusiasts, and it is now held in a parking lot and adjoining structure almost in the shadows of the earliest KLH and Advent factories. The place is full of exotic and esoteric laboratory-grade electronics gear that most people could never identify and it's also morphed into a computer marketplace, but there is also the more mundane plethora of knobs, switches, relays, tools, capacitors - - - you name it - - - as well as occasional vintage hi-fi. I spotted three pairs of early AR's plus one later pair, but alas, no Microstatics.

[genek]

The smaller ARs differ from the larger ones of the same era in two ways. One, of course, is that the bass extension doesn't go as far down. The other is that the dispersion of the cone or cone/dome combo tweeters is narrower than that of the domes in the larger speakers. The FR is similar, providing a "family resemblance" to the sound in direct listening, but the "airy" quality of the larger speakers' dome drivers is reduced because there's not as much of a reverberant field. The plus of this is that some people feel the smaller speakers image better, the minus is that the listening "sweet spot" is reduced. The Microstatics only add a small amount of additional HF to the direct sound, but widen the soundfield to something that more closely resembles that of the 2, 5 or 3 series speakers.

Also, the Microstatics do not replace the stock tweeter, they are an add-on device. The rear jumpers are not removed to use them.

[ra.ra]

Thank you, this is very helpful. Simply looking at the geometry of the Microstatics tweeter array seems to suggest this wide dispersion characteristic, so I can begin to appreciate that added attribute. I am by no means an acoustician, but what strikes me when I hear talk of "soundfield", "reverberant quality", "sweet spot" and "airiness", is just how every listener's situation must be unique and somewhat relative because of the many variables of individual room acoustics - - - proportions, size/shape, materials and texture, to name a few.

My misunderstanding - - - I had thought you were describing a situation where you take the original tweeter out of use and replace, not augment, with the Microstatics.

[Mario]

Hi, Thanks for all your post.

After few days the sound of the AR-6 became more open and now I have to say that is a very good sound.

Prpbably it was depended by many factors: the speakers was off for a long time and the new cap need a little burn-in. I have to say, when restore was finish, every day sound go better. Now I think the AR-6 have they originally sound and I like it, I use them in a small room and the sound is just a bit like the 3A in my other big room.

For the other idea "transformation in a little 3A" be quiet: I don't cut the AR-6.

This idea was start restoring many speakers system, I have restored Audiopro, AR, Advent,Snell, Miller & kreisel, Allison and many other, doing this, the original idea was to collect the best (for me) loudspeaker of the golden era and build a 3 way sytem.

I have the woofer of a Snell Type A and a Peerless tweeter Ko10DT, and I think to use the midrange of an AR-3a.

If this project take flight I will notice to you.

Mario