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39 minutes ago, brianw said:

Stimpy !!!     NIce pair of 58's .  Look to be in great shape.    I decided to go against the Mundorf supreme, part cost, part not going overboard.  And wanting to keep the flahship AR 9 as close as possible to it's design.  I am on the lookout for another pair of AR 9's,  AR90's,  Ar 9 LS,  or AR 9 LSi. to set aside for my next restoration project. 

In the meantime will be doing some very minor cabinet touch ups and a second coat of oil. 

Thanks!  I have to admit, I'm really impressed with the 58s speakers.  Detailed and dynamic.  Plus, the woofer blends much better, with the UMR, than I ever expected it would have.  No chestiness in vocals at all.

Also,  "I am on the lookout for another pair of AR 9's,  AR90's,  Ar 9 LS,  or AR 9 LSi. to set aside for my next restoration project".  It never ends, does it???  :blink::)

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25 minutes ago, brianw said:

So my other question is does anyone have any comments about the ferrofluid used in the tweeter and upper mid range of any of the AR speakers ? 

I have heard many stories and many that say it is still intact unless someone abused and over powered the speakers.

I have to admit, I've wondered about this too.  But, the speakers sound fine, so I have to assume that the ferrofluid is fine, as such.

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Get them  Nice sounding 8 in two ways. Put new surrounds on and a 5 uf cap in them. If you don't like them you can easily get twice your investment. Pictured below is the Ar18s, Original AR 18 and the AR18B. All very good sounding. Stay away from the ARbx and bxi.

4P6KuAi.jpg

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Which AR18 had the offset tweeter, with the rear level switch?  For whatever odd reason, they seem really unique to me.  I'd like to find a pair, one day.

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1 hour ago, Stimpy said:

Which AR18 had the offset tweeter,

Looking closely, you can see in larry's pic that the 18s (left) and the 18b (right) have the centered inline tweeters, and it is the original AR-18 (center) which has the offset tweeter.  It's been my understanding that only some of the original AR-18's included the tweeter switch, but I believe all of the original AR-18's used a 6uF cap while, as larry has already stated, the18s and 18b employed a 5uF cap. And, only the original AR-18 included the sculpted foam grille, which at this point, will most likely be difficult to find in sustainable condition.   

On 10/25/2017 at 9:32 PM, brianw said:

Anyone have any thoughts on the AR 18 B  speakers.

Despite my personal misgivings about this product's unfortunate budget aesthetic "styling", I agree with larry that it is a terrific small bookshelf well worth a simple restoration effort. 

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Still trying to get them.  Unfortunately I live on Vancouver Island, west coast of Canada, just above Belingham.   So the  speakers are in Vancouver which means a 2 hour ferry ride each way to go get them.   So going to try and have a courier service pickup and bring them over. 

But yes going to grab them if I can. Thanks everyone.

 

Briasn

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8 hours ago, ra.ra said:

Which AR18 had the offset tweeter,

You are talking about the original AR 18. All mine have the switch, but I believe michiganpat has a pair without the switch.

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Just happened to stop in a thrift store. Picked up a working pair of AR4 Xa  speakers.  20.00 
Need a lot of cabinet cleanup and new grills but they work just fine.  Only problem is some fool painted them flat black. is there any way to safely remove the paint or is just careful sanding the only way ?

 

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On 10/25/2017 at 9:15 PM, Stimpy said:

Thanks!  I have to admit, I'm really impressed with the 58s speakers.  Detailed and dynamic.  Plus, the woofer blends much better, with the UMR, than I ever expected it would have.  No chestiness in vocals at all.

Also,  "I am on the lookout for another pair of AR 9's,  AR90's,  Ar 9 LS,  or AR 9 LSi. to set aside for my next restoration project".  It never ends, does it???  :blink::)

Stimpy 

 

I just picked up a set of ar90''s

They sounded terrible when I brought them home.   

I recapped them today, what a huge difference.    Now smooth,detailed and just flat out awesome in the living room. 

I used auden poly on tweeter circuit, and plain Dayton NPE everywhere else with .01 poly bypass on mid and mid bass circuit.  Simple. Easy.  Great improvement.   These really do sound like the AR9 with a touch less bass (when you give it 2.5db on the eq).   I'm Impressed!!!   

 

You need to finish yours.

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Harry, that's great you were able to get good results with inexpensive NPE's.   Those AR90's look to be in great cosmetic condition as well.  Nice collection of large AR verticals you've got there as well as the 3a.

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Thanks AR surround

Yes, the Dayton NPE is really good.   In my first few recaps I did, I was mezmorized with all the info on caps out there.   On my second ar3a recap, I conducted an experiment in just doing it all dayton NPE.    The results was excellent.   great detail and smooth.  No harshness.    I am so confident in them, They will also go in the AR9lsi soon.  Its really all you need.....for far less dough.  

 

Since then, I have stuck with the dayton NPE on all caps, and have used the Dayton Poly or Audyn Poly on the ar tweeter circuit (since the ar speakers I have usually need a tickle more highs) and the results have been excellent.

 

The AR90 surprised me.   My Brother told me "they will be like the ar9, just need to add +3db on the bottom 3-4 freq on the eq)  he was right.  Placement is important though, like the ar9.

The ar90 in the garage after the recap sounded good, but Much better in the living room with the wall behind it.  The Bass output from the side firing woofer creates a different effect than the Front firing woofer of the Ar9lsi.  Placement is more critical with the side firing woofer.   I was very surprised how the 2  10 inch woofers performed....No typical 10 inch thumpyness.      The one difference so far in the ar9 and ar90 is one the midrange setting.   I started out with -3db on the mid on the ar9, then went to 0db.   I am still on -3db on the mid on the ar90.  time will tell.   But NO harshness, no irritation......and midranges can irritate my ear very easily.

 

ar9, ar90 are really good out of the box, the ar9lsi needs alot of tailoring to get it right, but once you get it, its Tremendous.   thats the sum up of the 3 ar towers...LOL    They really are great.

 

 

The 90's do need new Grill material. 

 

 

 

 

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On 10/25/2017 at 9:15 PM, Stimpy said:

Also,  "I am on the lookout for another pair of AR 9's,  AR90's,  Ar 9 LS,  or AR 9 LSi. to set aside for my next restoration project".  It never ends, does it???  :blink::)

Great. Competition ;)

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14 hours ago, harry398 said:

Stimpy 

 

I just picked up a set of ar90''s

They sounded terrible when I brought them home.   

I recapped them today, what a huge difference.    Now smooth,detailed and just flat out awesome in the living room. 

I used auden poly on tweeter circuit, and plain Dayton NPE everywhere else with .01 poly bypass on mid and mid bass circuit.  Simple. Easy.  Great improvement.   These really do sound like the AR9 with a touch less bass (when you give it 2.5db on the eq).   I'm Impressed!!!   

 

You need to finish yours.

 

I'm glad to see your cabinets in such good shape.  That helps.  Plus, it's good to hear the recap made such a profound difference in sound.  That's what I'm hoping for too.

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After I recapped my AR91's I noticed improved clarity, detail and much better imaging. However, using inexpensive caps yielded brightness/white noise and glare. They would get under my skin (listener fatigue) after 20 to 30 minutes. Pondering a change at this time.

 

Stewart, do you need me to come down and give you a hand with installing the xovers into your 90's? Dying to hear your impressions.

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3 hours ago, Stimpy said:

I'm glad to see your cabinets in such good shape.  That helps.  Plus, it's good to hear the recap made such a profound difference in sound.  That's what I'm hoping for too.

thanks Stimpy

I hope this prods you to get yours done.   :D

 

My brother picked up a set of 58s's  .  he did some work to them and has them sounding spectacular. 

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I know I'll finish them soon.  I've just been working through some health issues (herniated discs, kidney stones), that keep plaguing me!  One step forward, two steps back, lately.  But, I do a little here and there, as I can.  More a labor of love, than a race, I suppose?  So, the 90's will be finished, when they're finished.  I'm patient.  Doing it right.  But sometimes it feels, the Mundorf's I've used in the recap, will need replacing again, due to old age, before this is over with!  :o

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1 hour ago, Stimpy said:

.............sometimes it feels, the Mundorf's I've used in the recap, will need replacing again, due to old age, before this is over with! 

I don't think today's film caps deteriorate like npe and older film caps.

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So we have been listening to the AR 9's for a while with the CAP's replaced.  Used Mundorf  MCap Aluminum oil.  Extremely smooth, flat and clean, sometimes to flat.  After a few months of listening we quite often feel like there is a vale in front of the high end.  Often wanting to hear a little more openness, sparkle and air from the top end.  Have adjusted EQ and tend to push the mids / high end up a few DB.  So is this a choice of caps in the upper mid's, and tweeter as I have read several articles both on this board and others referring to different cap  brands producing different  results ?

As far as the bottom end, the two 12 woofers, I am being told to remove the large capacitors, 2500.00 and 470.  Anyone have any thoughts and hookup methods.  

mcap_evo.oil.png

 

174606932_AR9crossoverschematicclearer.thumb.jpg.64d61f5ecbe79461f2875a992faf8960.jpg
 

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Concerning the bass portion of the AR-9 crossover.  I suggest removing the 2500 uF cap - but NOT the 470 uF cap shunt to ground.   The 470 is a critical part of the 200 Hz low pass filter.  The 2500 uF cap was placed there to raise the impedance at resonance - otherwise the two 12" woofers are effectively in parallel with an impedance of about 2.8 ohms.  An amp killer - particularly in the world of 1979.   So if you do remove the 2500 uF cap make sure you have a modern solid state amp - no tubes need apply - that can handle low impedance loads. 

I have found two amps that are comfortable with that load; Odyssey Audio Khartagos and Pass XS150.5.  I am relatively certain that ANY Pass amp in his XS or XA models would work well with that kind of load.  There may well be other solid state amps that can handle such a load - but DO NOT try to drive the modified Nine with any "vintage" receiver - the result will be smoke, possibly flames and a dead receiver.  Nor try to use an H/T receiver - those things are at best rather flimsy in terms of actual power capability.

I have noted on my Pass amp, which has a bias meter on front that when I play heavy bass tracks that the needle swings in time with the music.  This means that the amp is coming out of pure Class A (about 16 watts maximum) and entering class A/B territory (300 watts into a 4 ohm load - actually about 10% more is typical Pass amp performance).  The bias is really increasing.  But the amp handles it with aplomb. 

I have measured results of this modification - F/R plots -  and posted them somewhere on the CSP - I think my results were moved to the "tweaks and modifications" section of the CSP.  I angered a few of the purists and know-it-all types by suggesting the modification.    How dare a mere peasant such as myself suggest such heresy as modifying the work of AR?  The response of the enlightened and insightful ones was to bury my comments and measurements in a part of the forum rarely traveled.  Oh well - males being males.  Competition and all that.

The sonic results of the modification?  Much tighter, deeper and tauter bass response.   As I recall the modification resulted in about a 10 Hz increase in usable bass down to about 25 Hz and a subjective sense of more bass across the band from about 80 Hz on down.  Try it.  You may well enjoy the response.

One other thing to check for - the 8" midbass coupler is in a "can" so it can employ air suspension.  That can was mounted to the front baffle of the Nine with a glue that has hardened and cracked over the intervening 38 years.  You should remount that can, which is made of thick cardboard and a thin piece of plywood on the rear, to the front baffle.  I used RTV as my glue and installed a brace between the rear of the can and the rear of the speaker.  Screwed in at both ends.  Keep that "can" airtight and get the original performance of the critical driver.

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One other comment.  When I rebuilt the crossover of the Mighty Nine I replaced all caps with decent (Erse, Jantzen, et cetera) film caps.  MISTAKE.  The upper midrange driver does NOT like having a film cap (24 uF) in its series feed.  I think AR_Surround was the fellow who first unraveled this mystery.  Placing a film cap in that circuit caused harshness, bite, congealing and grit in the playback of music.

While I haven't gone into the speaker to install the suggested Mundorf electrolytic I can say that the performance I have now is EXACTLY as AR_Surround noted - gritty, harsh and filled with hash at about 7 to 8 KHz.   I expect that installing the recommended Mundorf cap will fix that problem.

Also - see if you can replace the attenuator bank slide switches with toggle switches similar to what the AR-91 employs.   Much better switch.  The slide switches are hunks of crap - they collect dust and grit and tend to fail.

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31 minutes ago, valkyrie said:

One other comment.  When I rebuilt the crossover of the Mighty Nine I replaced all caps with decent (Erse, Jantzen, et cetera) film caps.  MISTAKE.  The upper midrange driver does NOT like having a film cap (24 uF) in its series feed.

Erse are not decent for series caps. What cap did you use for the 24uF spot ? Did you use a small bypass cap ?

I plan on using a Clarity CSA with a 0.01uF Cornell-Dublier 940C bypass cap in that spot. I have found the Clarity work well in other AR rebuilds.

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All I know about film caps is that they differ by orders of magnitude in price.   You can buy a 24 uF cap for $6 or $600 - guess which one I bought?  I do "believe" that Mundorf makes an exceptional capacitor.  Based on actual use and the reports of others.   But - and it is a big butt - I am not sure which cap I used in the UMR series feed.  It may have been a Jantzen, it may have been a Solen.  It was film - and that is what I was told to seek out.   I did NOT use a bypass.  

I do plan on going back into the speaker - which means humping its 132 pounds up on my work bench - always a joy!!!  I lean it against the bench and then lift the bottom up.   Ugh!!!!

So tell me about this "Clarity CSA".  Is it an electrolytic bipolar?   Or is it film?   The fellow who first determined the problem with the UMR series cap - I think it was AR_Surround - felt that the Mundorf electrolytic bipolar provided the smoothest response - with a film bypass.   Since it is not too expensive that is the direction I am headed.

Good luck with your endeavors - when I recapped my Mighty Nine it became a completely different speaker - quite delightful.  Sounds superb - better bass than a $60,000 Wilson (Strauss "Thus Spake Zarathustra" has a genuine low C organ tone - 32 Hz and the Wilson bass drivers jumped the gap on that note) - great clarity and superb dynamics.  To my ears a truly wonderful speaker.   You are fortunate to have such a speaker.  I am never going to part with mine.

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My 90's will be all NPE except the 350uF bass shunt as I already had the film caps. My 9's will be all film caps except the 470uF and 2500uF caps. I also have a Mundorf ECap70 NPE ready in the event the Clarity has the same issue as AR Surround experienced in the UMR.

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