The English Patient

[kimberley]

Greetings from the U.K. Until a couple of weeks ago I had never knowingly heard AR 'speakers: heard OF them, but they aren't common here in England. I've owned LS3/5as, Quad ESL63s, Sonabs, IMFs... (still own most of them) & have renovated a few (see preceding), but not AR.

Bought a pair of AR-2ax in reasonable cosmetic condition, with re-foamed woofers, otherwise probably unmolested. They are an 'English' (Houghton Regis, Bedfordshire) pair & I assume that the cabinets were locally made & the rest imported & installed - any information about the English operation would be of interest to me.

Trying them with AVI, Quad & Bang & Olufsen amplifiers was interesting, suggesting that the 'New England' sound is quite similar to the 'BBC' sound. This is not a criticism! Clearly the desire for accurate reproduction of real instruments playing real music is international & the laws of physics don't change much either! The slight 'bloom' on male announcer's voices sadly also seems to cross borders but I think it is often a studio phenomenon.

Treble appeared to be down slightly on one channel, enough to be noticeable, so I decided to investigate inside the boxes. The scratchy potentiometers were bypassed for the time being (yellow leads resoldered to the end of the rheostat track) without much benefit, so I replaced the capacitors & cleaned the potentiometers. The few of you who read this far might like to know that there was minimal corrosion of the wirewound track, & modest oxidation of the contact. After reassembly the 'dead spot' right at the top end of one track is still there! However, the balance is better between the 'speakers & I now have working controls to get the balance spot-on. I find my preference is for almost full 'boost' to mid & treble.

I had to repair a cracked surround on a tweeter, which I guess must be a common problem as the rim is a plastic material. For completeness I also pulled out the mid-ranges to reseal their seatings - what a surprise! For the (very critical) midrange to be passed through a fibreglass blanket through some chickenwire seems odd enough (I thought only British engineers, especially at the BBC, experimented with things lying around the workshop!) but the arrangement on the back of the magnet astonished me. AR actually exported the midrange with series 3-ohm resistors (x2) & a 4mF shunt capacitor! On the face of it, the midrange thus has a 4mF in series & another in parallel, which my modest electronic theory struggles to understand - so if anyone can explain?

I have rambled enough. Suffice it to say, I like my AR-2ax's. Should I now be looking out for some AR-3a's?

Adam Kimberley.

[JKent]

Hello Adam, and welcome!

If you have not already done so, I suggest you read the excellent booklet on AR3a restoration:

http://www.classicspeakerpages.net/library...ring_the_ar-3a/

Much of it is relevant to the 2ax and others. With any luck, you should hear from one of the authors regarding the unusual Brit variations noted. I knew the "European" ARs had different cabinets for the European market, but was not aware of the mod to the midrange (a mid mod?).

On the advice of RoyC I put a 25 ohm resistor across the back of the mids on my 2ax's, but that was to compensate for using an L-pad to replace the original potentiometers. I don't know what's going on with your mids, but someone more knowledgeable than I will probably respond.

And what's up with the chicken wire?? Or are we separated by a common language?  On this side of the pond, chicken wire is a very coarse mesh (maybe 1" openings) galvanized steel material used for temporary fencing, protecting gardens etc. Don't tell me THAT is what's in your speakers!!

I have used fiberglass window screening in my AR speakers to keep the fiberglass stuffing out of the drivers. AR originally used "kempac" paper, but Roy Allison used the fiberglass screening in his Allison line of speakers. Is that what's in your ARs?

Again--welcome. Hope we can help you.

Kent

 

[kimberley]

Hi.

Over here, 'chicken wire' is galvanised mesh, about the size you can stick a finger through - but not pull it back easily!

The bigger, 2-inch square fence is 'chain-link'. What I was referring to is expanded mesh - half the size of chicken-wire, but clearly holding the fibreglass (sorry, 'fiber', I do try to be bilingual!) blanket across the front of the cone.

The stuffing in the cabinet itself is probably rockwool - dark grey- (gray! there I go again!) brown & rather like woollen shoddy.

The midrange has a very 'Heath Robinson' appearance, but from looking at this 'site it is original. We British tend to like this kind of thing - it appeals to our 'make do & mend' spirit!

I did read the AR-3a rebuild advice before I started & found it invaluable. I wouldn't have had the nerve to take the potentiometers apart otherwise; I was surprised to find so little corrosion, but taking them apart & cleaning them has given peace of mind.

I inspected the mid-ranges only after I had replaced the crossover capacitors & promptly had to get out the soldering iron again to replace the newly-found, unexpected 4mF shunts!

I am listening to the 'speakers now: Joshua Rifkin playing Scott Joplin on LP ('vinyl') played on a B&O linear-track turntable (Danish) with a US Sound-Smith cartridge, with AVI amplification (English). Good music & good reproduction thereof shouldn't recognise borders!

Adam.

P.S. The New England & BBC 'Old England' sound have a lot in common: what possessed anyone to come up with the 'West Coast" alternative?

[Guest Audiomark]

P.S. The New England & BBC 'Old England' sound have a lot in common: what possessed anyone to come up with the 'West Coast" alternative?

A preference for Rock, presumably.

[JKent]

Adam, If you search here long enough you'll find reference to that European stuffing. Probably NOT rock wool, which is troublesome stuff that should be removed. I think a senior member (Minh perhaps) concluded your stuffing was similar to furniture stuffing and quite benign.

We have chain link here, too. I posted that photo of chicken wire. The holes are hexagonal and about 1" to 2" large (don't ask how many mm that is. How come we Yanks are the only ones using English measurement? Guess we're just backward).

Happy listening!

Kent

[kimberley]

Kent,

The 'stuffing' is indeed very like some furniture padding & seems very like what Bang & Olufsen used in small 'speakers. (At the same period, circa 1977, Sonab were using something resembling 'home improvement' loft insulation.

We obviously have smaller chicken wire because, being English, we have smaller chickens! And many of us do still use 'imperial' measurements: I still calculate my fuel use in miles-per-gallon, where, paradoxically, my gallon is larger than yours!

Can anyone give any pointers to curing an annoying 'buzz' in one (just one) of my AR-2ax mid-ranges? It's the curious 3,5" padded, mesh-fronted item & it adds a nasty 'kazoo' effect on frequency sweep from about 2-3kHz. Tightening or loosening the screws doesn't help, neither has bedding it in Blu-tack.

Adam.

[JKent]

Oh THAT chicken wire! On the FRONT of the mid. Duh. I was thinking about stuffing when you mentioned fiberglass. Yes--the ARs and KLHs had fiberglass and screening over the mids or tweets. Dunno why.

As for your other questions, here are some comments from RoyC:

Mid-70's ceramic magnet woofered 2ax's had 3 ohms in series attached to the mid, which was later replaced by a visually identical, higher impedance midrange. This has been mentioned a number of times in the forum.

The added 4uf cap, however, is new to me. I'm guessing it shaved some highs off the midrange, as the later back-wired tweeters had more output.

Hope that's helpful.

Kent

[Diamonds&Rust]

Can anyone give any pointers to curing an annoying 'buzz' in one (just one) of my AR-2ax mid-ranges?

It would probably be easiest to see if someone here has another of those midranges they might be willing to part-with. One of the negatives of the fiberglass on the front of those drivers is that you can't see the driver's cone or suspension.

There are just too many things that might be wrong and too few ways of seeing it. And I'm not sure you could fix it if you could identify it.

HEY EVERYBODY ! ! Does anyone have a spare 2ax midrange laying around you might be willing to mail to England? Or are we going to let an Englishman and fellow ARer down?

I'm sorry I don't have one, Adam.

Bret

[KlausDK]

HEY EVERYBODY ! ! Does anyone have a spare 2ax midrange laying around you might be willing to mail to England? Or are we going to let an Englishman and fellow ARer down?

Hi Adam

I have a spare AR 2ax mid with resistors, capacitor and all. I haven't heard it, but it reads 7 Ohm DC resistance on the terminals and (not surprising) 13 Ohm through the two 3 Ohm resistors.

Send me a PM if you are interested.

The resistor/capacitor arrangement indeed looks strange on this driver; I seem to remember another thread about the AR-2ax mid, where an esteemed member of the site expalined the story behind and why and when they appeared/disappeared, but I can't locate it.

BRgds Klaus

[kimberley]

Hello again, & my thanks to you for your thoughts & kind offers.

Further investigations & work on the AR-2ax's had to wait due to work & my daughter's 12th birthday & attendant celebrations - probably a good thing as it gave time for the disturbed drivers to settle down & for the new capacitors to charge & discharge a few times.

The 'buzz' (or kazoo effect) is cured, I hope. Frequency sweeps showed it to be around 2 - 3kHz, (particularly annoying as my test disc has fixed tones at 1 & 4kHz, but nothing between) & definitely from the mid-range driver.

Close inspection with a stethoscope & a finger revealed that the expanded mesh in front of the fiber-glass pad (or fibre-: they were U.K. assembled!) was vibrating, which didn't happen on the other channel. One side of the mesh had detached from the driver rim & the other three sections were carefully prised off - actually very similar to removal of a large scab from a grazed knee (for those of us who care to remember the hazards of short trousers as children). The mesh seemed to be held in place not by glue, or the mounting screws, but by black thick 'goo', so I rejevenated & augmented this with black silicon sealant.

There remains an overtone lower in the range, but this is slight & only at quite high volumes & I think it best left for the present.

Looking at pictures of other ARs from the same period (particularly AR-2ax) there are some detail differences. My Bedfordshire pair are finished in teak veneer, which was very fashionable here in the 70's, when Scandinavian design was a great influence. The most noticeable oddity is the front lip of the cabinet, which has a slightly undersized 'fillet', probably solid wood, slightly darker than the teak. This isn't an expected styling feature for the English Hi-Fi market, as my Rogers LS3/5a's & my IMF Studios & SuperCompacts have similar plain 'wrapped veneer' fronts to all the US AR photos I have seen.

Does anyone have information about which models were made in the UK & when?

I am listening to them now & am very impressed. As a 'neutral' transducer should be, they seem to do a very good jog with all genres of music, particularly open-sounding with chamber music, but quite happy with Eric Clapton, too. Actually, on the Beatles/George Martin 'Love' remastering, I heard detail which I had never noticed before.

Adam K.