my new AR9's

[Joel]

I've been working on my friend for over a year to get him to sell my his AR9's, and he finally agreed. He bought them in the early 80's, around the same time I bought my AR90's. The foams need to be replaced, and he has stored them in a closet for the past 10 years. I should be picking them up next week.

Anyway, I am giving my AR90's to my daughter. I had AR90's refoamed a couple of years ago, and replaced the caps last summer. They sound terrific, and I know she will appreciate them. She already has my old JVC amp that I originally used with these speakers.

I will drive the AR9's with a Dynaco 416 amp, so I should be ok for power.

My question is: Is the cap list the same for the AR9's as the 90's? From what I have read, I would be better off leaving the two largest caps alone, but are the rest the same?

-Joel

[soundminded]

I recapped mine in the fall of 2008 while Millersound was refoaming the woofers and LMRs (Bill did a great job as he always does.) I changed all of the caps exceopt the two large cans. Go by the values printed on the caps, as I recall one of the caps on the schematic in the wiring diagram is wrong. I used ordinary non polarized electrolytics I bought from Parts Express and I'm very happy with the results. Sounds as good as new, maybe better.

[fordf250]

Hello Joel-I have two AR9's that I bought in 1979, or 1980. I refurbished them last Feb, including all the capacitors. There have been may conflicting opinions about the Callins 2500mf, in the woofer circuit. I replaced the Callins 2500mf's in both units--the bass response change was immediately improved, to my ears: tighter, more articulate, and just as extended as before the change (all cone drivers were also refoamed). I would say maybe the refoaming had something to do with it, though the foam on the 4 woofers was still intact, as was the foam on the 8 inch upper bass driver.---I believe that changing the 2500mf cans was responsible for the marked improvement.

If I hadn't replaced the 2500's, along with all the rest, I would always have been wondering if the sound could have been improved further---I felt if I didn't like what I heard, I could always put the Callins back in--I was richly rewarded for the change.

[Joel]

Do you have a list of the caps that you used? I looked at the schematics, but I'm not good with that kind of thing. I don't have the speakers in hand yet, so I can't look inside. I was hoping I could just redo my order from my AR90's.

Where did you get your replacements for the 450 and 2500's? Or did you bundle to get the correct values?

-Joel

[kkc]

Have look at http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=5966&st=0&p=84968entry84968 for the rebuild I did. I replaced the big woofer caps and am very happy with the result. Having experimented with the switches, I could have left them out entirely as in practice I don't pipe any signals through the switch resistors. These are really fantastic speakers that put modern speakers costing thousands to shame...! I love the fact that I can position them next to the back wall too...!!!

[fordf250]

Hello again Joel-the following information should help you out:

1.I bundled capacitors (connected in parallel) to get the 2500mf. You can find all the capacitors you will need a www.erseaudio.com and www.meniscusaudio.com. The big capacitors 1000mf and 500mf, that you will need, if you bundle, are at meniscus-click on he erse icon there. REMEMBER THE FOLLOWING-YOU CAN ALWAYS USE CAPACITORS OF HIGHER WORKING VOLTAGE, THEN CALLED FOR, AND NO PERFORMANCE WILL BE AFFECTED.

2.Capacitor list, as called out on schematic (all are quantity 2, for doing two AR9's:

2500mf/60vdc/npe

470mf/50vdc/npe

30mf/50vdc/npe

80mf/100vdc/npe

8mf/100vdc/tubular

40mf/50vdc/npe ot tubular

24mf/100vdc/tubular

6mf/50vdc/tubular

4mf/100vdc/tubular

Hope this information helps somewhat-if you have problems reading the schematics, you can identify the capacitors, and locations, once you get your units. Good Luck

[kkc]

In addition to the info from fordf250, you should always attempt to bundle caps of the same value e.g. 2 x 50uF instead of 1x 25uF and 1x75uF. This will help to keep unnecessary harmonics down resulting in a cleaner sound. Also using the Vishays as I did is supposed to help and since they are really cheap. Good luck...!

[Joel]

I picked up the AR9's today. The drivers are at Midwest Speaker Repair for refoaming. The crossovers in the two speakers are quite different from each other. I've know the original owner for 40 years, and know the history of these speakers. I am pretty sure they have never been opened before. The serial numbers are 014545 and 011902.

I am going to replace everything except the 470uf and the 2500uf. I can always change them later if I want to.

Based on the pictures, is there anything I should know before I proceed?

-Joel

[fordf250]

They are not that different-first of all, the two pictures, of the bottom xover are taken from different sides of the enclosure. The 011 has all the old capacitors-they must have had a million of them-mine are in the 007 series and look exactly like your 011-they had to go to the store to get some new ones for your 014.

Board in the base is the woofer/upper bass board. Vertical board is the midrange,tweeter board. Donot try to remove the boards-work on the xovers through the bass driver holes. Easiest to work on bass board with enclosure upright; upper midrange/tweeter board with enclosure horizontal.

Change capacitors one at a time-be sure of value match. Cut leads close to body of cap to be removed-if doesn't come out easily, mount new one next to it-make mechanical connection (twist) with new leads, and old leads, not attached to old capacitor, trim and solder. I glued my new capacitors in with silicone adhesive. Remember, none of the capacitors are polarized, so there is no wrong direction.

[kkc]

if you intend to have all the new caps inside the speakers, be sure to replace with electrolytics - polypropylene caps will be too big...!

[Joel]

I just ordered the caps. I went with pulseX Polypropylene caps, except the 470uf I used Electrolytic. I used these when I did my AR90's, and I didn't have any problem with the size of the caps. The AR9 looks like it has even more room than the 90's had, so I should be OK. The crossovers are going to be alot easier to reach on the AR9's as well.

-Joel

if you intend to have all the new caps inside the speakers, be sure to replace with electrolytics - polypropylene caps will be too big...!

[Mach3]

Sorry - but the bottom crossover board is designed to BE REMOVED - it is held in place by nuts on some bolts. So when you work on this crossover you are much better served by removing it. The hi/mid crossover is glued in place and CANNOT be removed. You will have to access it via the woofer hole. Plan on pulling BOTH woofers as you will need access from both sides - plus the extra opening helps you get the solder resin smoke out of the cabinet ;-)).

By all means - replace the 2500 uF cap AND the 480. I used ganged electrolytic capacitors (5 * 500 uF) caps from Parts Express. For the 480 I spent the money to get a Jantzen (?) film (maybe Solen - don't remember) - it was HUGE. Replacing these low end caps will DRAMATICALLY IMPROVE your bass response - deeper, tighter and far richer tonality.

Something that is very important - your 8" mid-bass driver has an air chamber behind it that is glued to the back of the speaker baffle - that glue is 30 years old, has hardened and this chamber is no longer actually attached - it is being held in place by the wires going to the 8" driver. You will have to remove the 8" driver, pull the chamber out (approximately 3.5" deep and about 10" across - a cylinder made of thick cardboard with a pressboard top (similar to the crossover board material)).

To get this chamber back in place I used a brace that extended from the back of the chamber to the back of the cabinet (screwed and glued at both ends). Working with this thing is a MAJOR b*tch - as in major. Once you have the chamber and its brace in place reseal the chamber to the speaker baffle with RTV (aquarium glue - a clear pookey that forms a rubber). This will take about 4 hours to dry completely. Good stuff.

Also - your bass crossover has beaucoup coils all over the place - try to mount these coils so that they are at right angles to each other - this will reduce induction between the coils - do NOT use ferrous bolts to mount the coils - use brass with the appropriate brass nuts/washers. Since you have the bass crossover board OUT this will be easy to work with.

Another important suggestion - rewire ALL your drivers and solder the wires in place. I used flat OFC wire - and used doubled runs on the woofers. The original wire and the spade clips are just terrible. Wire PAST the attenuator board - the switches used in that board were crap the day they were built and 30 years of seasoning has NOT improved their sonic qualities. I straight wired from my crossover points DIRECTLY to my drivers. I did not remove the attenuator board and its 6 resistors - you may if you wish but it is tough to get that thing loose from the cabinet.

The only downside of not using the stock attenuator board is that you will have to tune your response to your room by going into the crossover and soldering another resistor in place (DO NOT USE WIRE WOUND RESISTORS - use the original ceramic style). To save yourself some time you can place ALL your resistor values on the crossover board and then it is simply a matter of lifting a wire and soldering it to another resistor (wire the "out put" side of the resistors in parallel - only the one that you connect to the input will be in the circuit).

So when you reinstall your woofers make sure one woofer is only using a gasket - this way you can easily remove that woofer when you tune your attenuation response.

I fired mine up after a complete rebuild with no attenuation - too hot for my room. Had to go back in twice to increase the attenuation on the mid-range and the tweeter. Still just a little hot around 7k.

One other thing - you will find an extra coil in parallel with your mid-range - this coil is NOT on the schematic - but please do not remove it - it tightens up the pass band of the mid-range dome by upping the inductance that the driver presents to the crossover.

Good luck and if you need some help don't hesitate to ask.

I have included a spectral plot of my Nines in my living room - the red vertical bars are the crossover points - note that I have a bit of a bump in the 7k region - this means that my crossover "laps" at that point (Where the mid-range passes over to the tweeter) - in other words the crossover as I rebuilt has some overlap, i.e. both drivers are playing - or more accurately the mid-range is playing outside its band. I have to fix this.

Also a picture of the low band crossover pulled out as I work on it.

[Mach3]

yet another thing to do - that hard brown glue used to attach your caps and coils to the crossover? That stuff is gone with the wind - so to speak - it is hard and provides no vibration control for your components. It comes off really easily with just a tap from a chisel or a screwdriver. Remove that stuff. When you place your new caps and coils to the board mount them using RTV (the clear pookey that is sold as "acquarium glue" - it is RTV which stands for Room Temperature Vulcanizer - which means it is "rubber in a tube" - great stuff - strong glue, great vibration mounting and easily removed).

Good luck.

[rrcrain]

A couple comments about the crossover boards and glue.

The same dried out glue that holds the upper mid driver in place was used to hold the upper crossover board in place. The board can easily be removed and reinstalled using a good silicone adhesive.

Been there, done that.

These are wonderful, old speakers. Replacing the caps with new is a good thing to do, but do not get carried away on what you spend. These are old speakers afterall.

[Joel]

I've read a lot of thread on restoring the AR9, but this is the first I have heard of the chamber behind the LMR being a problem. Has anyone else run into this? Mine seems to be intact, but I don't want to push on it too hard.

Also, there was a long thread from a couple of years ago about replacing the 2500uf. The conclusion in that thread was that bundling to get the correct value wasn't as good as leaving in the original. Is that still the recommendation? If a bundle is recommended, would all 500's be better than 2 1000's and a 500uf?

Thanks.

-Joel