lance G

Many thanks to you Giovanni, Attached picture is of one of my original crossovers before recapping all EXCEPT for the 2500 uF. Apparently mine are Callins as yours were, so seems like it's time to change them out ! Your information is really useful to me as I was given the impression, including from the forum, that it was acceptable to leave the 2500uF cap's in place as they are considered to be "historically robust".

Hi Giovanni. Most unlike you to not come back on this ?🙂. I (and likely others?) would be very interested in how far out the big cap's were ? Also which make (brand) they were ? Thanks in anticipation, Lance.

Particularly interested in this; "especially those in the 2500uF impedance compensation". Were they far out ? Many seem to say to not bother changing these, I suspect partly because of some difficulty in finding the correct value/s ? I am in the UK and may well have to resort to purchasing from the U.S. (Madisound or other ?) with the additional costs of doing so.

Result, and within 7 hours the OP has the answer ! To top it all it's one he wants to hear. Hats off to fedeleluigi !

So disappointed to see him downloading the latest music editing software on that old laptop. The day the music died.

How many got neither ?!!!

I can sense your excitement from here !

Check your wiring is correct against an accurate wiring diagram. The following may help, or after fully reading make things worse !!! https://community.classicspeakerpages.net/topic/16982-ar-90-first-time-listen-and-amplifier-pairing-question/page/2/

Maybe some new capacitors in the crossovers might be needed ?

Thanks, always good to have a definitive answer !

No stuffing ever installed from new, and not required ? This due to only very low frequencies and a requirement for large air volume movement in this area of the cabinet/s.

Not much help I know but it would be more of a sin if you could send indecent photo's ! Let's not discuss the rediculous size aspect !

I must bow to RoyC's superior knowledge but my personal thoughts are: For the speakers to make any sound a signal of some level has to be reaching them. If they were disconnected altogether there obviously would be no sound. They are passive devices, I would be be looking elsewhere. Perhaps the capacitor change has made the speakers more sensitive and you can now hear a signal that was always there ? I guess some form of RF or induction could be responsible ? How far away are your electronics from the speakers ?

Below taken form the AR9 manual, I suspect it's the same for the AR90. http://www.classicspeakerpages.net/_Media/ar9_or_manual_page32-2.jpeg

I personally would be inclined to leave the high range and upper midrange drivers in place during any restoration. The inset foams surrounding the drivers are rare and unobtainable now, I would expect the foam to crumble if any attempt were made to remove it in an effort to reach the driver securing screws underneath. It's nice to see a set still on a pair of speakers, most seem to have disappeared now. Put some sort of protection over the drivers, perhaps some sturdy card or thin plywood whilst restoring the rest, cabinets etc. I don't think there would be much to gain by removing these upper drivers anyway, crossover (which is situated in the base behind woofers) callins capacitor replacement is more relevant to any refurbishment/rebuild. I have AR9's now, but had a pair of 90's previously. I loved them, and they are physically easier to live with than the larger 9's. You have the makings, after sympathetic restoration of the cabinets, grille cloth and badges, and (likely) crossover capacitors, of some superb speakers. I would go on to say enjoy, but it sounds like you already are ! Footnotes; Check out images on the internet for confirmation of the original black painted cabinet areas. Quite simply it's the backs and the areas usually covered by the grilles. AR9's are fully veneered other than the backs which are black. Of note the upper midrange drivers are unique to the AR90 and AR9's, another good reason to leave them alone, fortunate that these have not been pushed in unlike the lower midranges. Pulling out with tape should hopefully sort those and at the end of the day they are only dustcaps which could be relatively easily replaced. Finally, your cat is apparently an exhibitionist !

That's a very sweet choice of music, Donald Fagen, The Nightfly. One of my go to albums. You should get a great deal of pleasure from what you have, thoroughly enjoy !

I think the following applies to your amplifier ? It may be of some relevance to your perceived issue ? IMPEDANCE SELECTOR switch Do not change the IMPEDANCE SELECTOR switch while the power of this unit is turned on, as doing so may damage the unit. If the unit fails to turn on, the IMPEDANCE SELECTOR switch may not be fully slid to either position. If this is the case, remove the power cable and slide the switch all the way to either position. Select the switch position (LOW or HIGH) according to the impedance of the speakers in your system. Rear panel CAUTION Switch position Impedance level HIGH • If you use one set (A or B), the impedance of each speaker must be 6 Ω or higher. • If you use two sets (A and simultaneously, the impedance of each speaker must be 12 Ω or higher. • If you make bi-wire connections, the impedance of each speaker must be 6 Ω or higher. See page 6 for details. LOW • If you use one set (A or B), the impedance of each speaker must be 4 Ω or higher. • If you use two sets (A and simultaneously, the impedance of each speaker must be 8 Ω or higher. • If you make bi-wire connections, the impedance of each speaker must be 4 Ω or higher. See page 6 for details

You were relatively lucky. This was mine !

Well done ! That should be enough, quit while you're ahead. My driver was far, far worse that yours. I think mine was likely subjected to freezing temperatures and pressurisation in the aeroplane cargo hold which totally reversed/collapsed the complete dome. Report back when the rest of the work is done with an update, and enjoy !

This will not make any difference. You could remove the driver altogether and it wouldn't help, other than you will likely be able to confirm that it's a (to my mind, in my experience an apparently?) sealed unit. From what I can see in your picture I would personally try using the tape method for starters, but you will need a tape that is strong enough to stay adhered while you gently start pulling, but of course can then be readily removed when you have hopefully succeeded. Perhaps first gently heat the cone with a hair dryer (?) and keep a gentle sustained pull on the tape to allow time for any air to (hopefully via somewhere!) find its way back into the space behind the cone, thereby re-balancing the internal with the external air pressure. Not something I would ultimately be keen to try, but perhaps a worst case MIGHT be to gently insert a small needle tip just through the centre of the indentation to both allow some air into the driver and to tease out the dent. A tiny drop of clear sealer of some type could be used to seal the hole. Again I would try this on a previously warmed cone. DISCLAIMER ! All the previous is based on my own experience and opinions. Please don't blame me if when (perhaps foolishly😀) following my suggestions you bugger it up ! Perhaps wait a little longer for other members, who very likely know far more than I, further input while you crack on and replace the perished woofer and lower midrange foams ?👍 And as the sage Stimpy very wisely suggested change the (if relevant) Callins capacitors.

I have had the same issue with a used (identical) driver imported from the USA into the UK for my AR9's. I think the pressurisation/temperature change during the flight likely caused what amounted to the total collapse/inversion of the cone. I don't personally think that wetting will make much difference, the cones seem to be coated (sealed?) with a type of tacky/sticky resin (therefore airtight?) I do wonder if the units are sealed ? or at least pretty much airtight, it appears that there is a battle against an internal vacuum when in my efforts to pull the cone out, as you also seem to have experienced, just saw the cone being apparently sucked back in. I ultimately had some reasonable/moderate sucess by gently heating, the use of tape and the gentle, dexterous use of a vacuum cleaner. In the end not a perfect result visually, but at least it resulted in an apparently serviceable driver. I suspect very gentle efforts, trying to allow some time for air to gently "flow" back inside the driver is the way to go, "little and often" or "softly, softly catchee Monkey" would seem to be the order of the day ! I believe the driver is a 200028-0? Used only in the AR9 and AR90 models. Getting hard to find good working replacements now, so do take your time and exercise caution. I had AR90's in the past and loved them, I eventually got my bucket list AR9's here in the UK. IMHO any careful effort you put into your speakers will likely be richly rewarded, they are cracking speakers, easier to live with than the AR9 (physically), and right up there sound wise. Good Luck ! And do please update us on your efforts.

Hi David, thanks for the quick reply, and don't apologise regarding the 606, it is after all a U.K. amplifier. Your interesting observation from the AR9 manual regarding an impedance dip to 3.2 ohms is interesting. I did today find an old Quad 606 amplifier review (http://www.meridian-audio.info/public/606[2223].pdf) which states to quote; "it should be able to drive any loudspeaker except those dipping below 3 ohms", so hopefully, if correct, this should be re-assuring. However I wonder what the seperate minimum impedances might be for each seperate AR9 circuit when bi-amping ? With one 606 amplifier driving the lower midrange, upper midrange and tweeters, and a seperate 606 amplifier for the bass drivers ? On brief inspection my CT-Seven has only one pre-out, but although not ideal, I do have a cable splitter to enable me to send a signal to each 606 amplifier for bi-amping.

I appreciate this is a mainly U.S. biased forum, but I do have a question from the other side of the pond in the U.K. Anyone have opinions on driving the AR9 with U.K. manufactured Quad 606 amplification ? I perceive that the AR9 thrives on plenty of power ? I am currently using a single Quad 606 and have another 606 which I have dabbled in, and can dabble again with bi-amplification. Again I perceive that the AR9 can "dip" to around the 2 ohm load area but have found it difficult to confirm the suitability of the Quad/s in this regard. I use a Carver CT-Seven pre-amplifier as I like the convenience of the remote control volume and switching. I have, and have tried a Carver PM 1200 amplifier, but I found it hard to live with the cooling fan noise and I have tried to avoid any fan modification (silencing) to date. Any (polite) suggestions or opinions from the more technically minded greatly appreciated !

Hi Frank, Sorry to hear you're not in the UK. I was initially intrigued because I am not sure how many AR9's made it or were assembled over here. Regarding the Mundorf NPE's and my earlier posting which it appears you have seen ? To be honest at that time I didn't know what I should expect. The cap's in my speakers when I inspected them were obviously original, and the speakers sounded good, to me, when I first got them used from here in the UK. I changed the cap's, I think it was two years ago, very largely on the basis that they were obviously pretty old and likely past their best, and I guess I expected to hear a, potentially radical, change/improvement once the new cap's were fitted. With this in mind I perhaps felt a little disappointed when this apparently wasn't the case. However I do now have peace of mind that the cap's are good for some time to come, and are both in specification and of the type originally fitted. I did test the Mundorf's before fitting, and also tested the old cap's when they came out. I do recall that some of the old cap's had drifted but not to an obscene degree. I am also now more at ease that potential danger of damage to the very hard to find/replace here in the UK drivers, has hopefully been minimised. Regarding the subjectivity of any listening outcome, I feel sure you will be aware there are a lot of variables. Not least personally to me is my increasing age and no doubt as a result the reduction in my hearing of the higher frequencies. In closing, HI FI collective were nothing but professional in my dealings with them, and I think it unlikely that you will have made a mistake by using the Mundorf's. I see people dabble with other capacitor types, but I considered that the original amount of research and development warranted the use of OE specification capacitors to retain a sound as near as possible to the original, sound that was so highly regarded at the time the speakers were released. I hope the above helps, both yourself and shacky. Lance.

Frank. Some more AR 9's in the UK ? Let me/us know the result/outcome of your efforts. I too used the Mundorf E-caps from Hi Fi Collective. I left the big cap's in place, for now. Nice one !