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System Questions Around AR-11's


Guest Mike Slate

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Guest Mike Slate

Assembling a new stereo system around my AR-11's with the following questions, please:

1. Room is small (11'7" x 14' 10"). Are the AR-11's too big or can I do well with sensible volume levels?

2. I am considering an Anthem 225 integrated amplifier (310W RMS @ 4 ohms both driven) vs. 100 watts nominal; 150 maximum and 225 peak I believe are the specs for AR-11's. Should I fuse the lines to the speakers to avoid blowing them out or can sensible volume levels protect my precious speakers?

3. I purchased the AR-11's new in 1978. The woofers required new surrounds about 10 years ago at which time the repair facility went through everything and even gave me a print out from test gear that tracked each speakers output on a graph from the bottom to the top of their dynamic range. They still sound just fine. May I therefore assume they have suffered no unknown deferred maintenance?

4. If their age indicates a check-up is in order, what should I look for?

Thank you all. Mike Slate

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Hi Mike and welcome

The worst threat to speakers is amplifier clipping, caused by over-driving an under-powered amp. A big honkin' amp will not hurt speakers at normal listening levels in a room that size. Nice amp btw.

There's a thread on AR-11s here:

http://www.classicspeakerpages.net/IP.Boar...25&hl=ar+11

It has a photo of the crossover, which shows those crappy old black and red Callins caps. If you have those, you should consider new caps.

Good luck!

Kent

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Guest Mike Slate
Hi Mike and welcome

The worst threat to speakers is amplifier clipping, caused by over-driving an under-powered amp. A big honkin' amp will not hurt speakers at normal listening levels in a room that size. Nice amp btw.

There's a thread on AR-11s here:

http://www.classicspeakerpages.net/IP.Boar...25&hl=ar+11

It has a photo of the crossover, which shows those crappy old black and red Callins caps. If you have those, you should consider new caps.

Good luck!

Kent

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Guest Mike Slate
Hi Mike and welcome

The worst threat to speakers is amplifier clipping, caused by over-driving an under-powered amp. A big honkin' amp will not hurt speakers at normal listening levels in a room that size. Nice amp btw.

There's a thread on AR-11s here:

http://www.classicspeakerpages.net/IP.Boar...25&hl=ar+11

It has a photo of the crossover, which shows those crappy old black and red Callins caps. If you have those, you should consider new caps.

Good luck!

Kent

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Hey Mike

Looks like your replies are not showing up. FYI here is a schematic for the 11:

http://www.classicspeakerpages.net/library..._schematic.html

Looks like you need 10uF, 40uF, 50uF and 72uF for each speaker. There's also a 2 amp fuse so I'd suggest getting a spare.

Madisound has Solens in 10, 40, 50 and 70 (close enough). To save some dough you could use madisound's surplus caps for the 10s (0.60 ea) and maybe parallel them for 40 and 50. Or use Carli 10s ($2.07 ea if you get 10). Don't think I would bunch 7 together for the 70, so either use the Solens of try Bennic non-polar electrolytics (parallel 30 + 40 for under $3).

Or, if you like Daytons, Partsexpress has them in 10, 40, 50 and 75 (again, close enough) but they seem a bit pricier.

good luck

Kent

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Comment on AR-11 schematic:

This is a VERY early schematic. As Tom Tyson noted, I’m not sure the 2 amp fuse was ever included in production AR-11s. I’ve never seen an AR-11 with the fuse. Also, the parallel 72uF and 50uF caps were replaced with a single 120uF cap in the woofer section – silver Callins can – when the AR-11 crossover was reconfigured from a 2 board to a single board crossover.

Mike,

Since you purchased your AR-11s in 1978, I’m assuming they are what we refer to as “AR-11B” –black/silver badge and foam around tweeter. I purchased mine that same year.

If you remove the woofer look at the crossover for burned resistors (blackened hot melt glue between resistor and board it’s attached to). If glue is still white, the resistors should still be good. The inductors and wiring should also be OK. Have the caps individually tested. They most likely are due replacing as Kent has stated.

10uF and 40uF caps are readily available. You may have to parallel 2 or more caps to get a 120uF cap. I’ve had good experience with Solen caps, not so good experience with Daytons. I haven’t tried Bennic or Carli caps yet.

Your amp/AR-11 combination should work well in a ~ 12X15 room. At “sensible” volume levels you will have little risk of amp clipping and damage to your AR-11s. I’ve powered my AR-11s for years with 300 wpc into 4 Ohm amps with no damage.

Hope this helps

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Comment on AR-11 schematic:

This is a VERY early schematic. As Tom Tyson noted, I’m not sure the 2 amp fuse was ever included in production AR-11s. I’ve never seen an AR-11 with the fuse. Also, the parallel 72uF and 50uF caps were replaced with a single 120uF cap in the woofer section – silver Callins can – when the AR-11 crossover was reconfigured from a 2 board to a single board crossover.

Thanks for catching that! I have not opened an AR-11 so was just going by the schematic.

Making up 120uF will give more options. PE has a 125uF NPE for $2.20 ea. Solen 100+20 in parallel would be about $43 per speaker. Dayton 60uF x 2 would be about $30 per spkr. Madisound has 120uF Solens for about $35 ea. Bennic 125uF for about $3 ea. Then there are Clarity Caps--about $60 for 100+20.

If I were doing it, I'd use the 125uF Bennics and save the difference for CDs. If I were set on polys, the 120uF Solens look like a good choice. You may hear MANY conflicting opinions on cap choices. This part is fact:

1. originals were NPEs

2. film caps last longer than NPEs

All else is opinion/taste. I'm one of those who do not believe that speaker wires or interconnects have special audible qualities, so you know where I'm coming from wen I say the Bennic NPEs should be just fine. Whatever you choose, they will be better and last longer than what's in there.

Kent

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Guest Mike Slate
Hi Mike and welcome

The worst threat to speakers is amplifier clipping, caused by over-driving an under-powered amp. A big honkin' amp will not hurt speakers at normal listening levels in a room that size. Nice amp btw.

There's a thread on AR-11s here:

http://www.classicspeakerpages.net/IP.Boar...25&hl=ar+11

It has a photo of the crossover, which shows those crappy old black and red Callins caps. If you have those, you should consider new caps.

Good luck!

Kent

Thanks. For now, I've got to just learn how to send a reply! Sorry. Tnx - -M.

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Guest Mike Slate
Comment on AR-11 schematic:

This is a VERY early schematic. As Tom Tyson noted, I’m not sure the 2 amp fuse was ever included in production AR-11s. I’ve never seen an AR-11 with the fuse. Also, the parallel 72uF and 50uF caps were replaced with a single 120uF cap in the woofer section – silver Callins can – when the AR-11 crossover was reconfigured from a 2 board to a single board crossover.

Mike,

Since you purchased your AR-11s in 1978, I’m assuming they are what we refer to as “AR-11B” –black/silver badge and foam around tweeter. I purchased mine that same year.

If you remove the woofer look at the crossover for burned resistors (blackened hot melt glue between resistor and board it’s attached to). If glue is still white, the resistors should still be good. The inductors and wiring should also be OK. Have the caps individually tested. They most likely are due replacing as Kent has stated.

10uF and 40uF caps are readily available. You may have to parallel 2 or more caps to get a 120uF cap. I’ve had good experience with Solen caps, not so good experience with Daytons. I haven’t tried Bennic or Carli caps yet.

Your amp/AR-11 combination should work well in a ~ 12X15 room. At “sensible” volume levels you will have little risk of amp clipping and damage to your AR-11s. I’ve powered my AR-11s for years with 300 wpc into 4 Ohm amps with no damage.

Hope this helps

Like yours, I do have the AR-11B's. I found single Solen capacitors at exactly the 120uF capacitance at Madisound. Seems a good way to go for not too much to avoid having to parallel others.

Also, the foam surrounds for my tweeters are in fairly good condition. Would you suggest I leave them alone for now or consider the felt surrounds offered by Vintage AR?

Gee, I really appreciate everyone's help. I've listened to today's speaker technology on the market and I cannot find anything below $6,000 with my ears and preferences that compare to our AR's. Tnx - -M.

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Guest Mike Slate
Thanks for catching that! I have not opened an AR-11 so was just going by the schematic.

Making up 120uF will give more options. PE has a 125uF NPE for $2.20 ea. Solen 100+20 in parallel would be about $43 per speaker. Dayton 60uF x 2 would be about $30 per spkr. Madisound has 120uF Solens for about $35 ea. Bennic 125uF for about $3 ea. Then there are Clarity Caps--about $60 for 100+20.

If I were doing it, I'd use the 125uF Bennics and save the difference for CDs. If I were set on polys, the 120uF Solens look like a good choice. You may hear MANY conflicting opinions on cap choices. This part is fact:

1. originals were NPEs

2. film caps last longer than NPEs

All else is opinion/taste. I'm one of those who do not believe that speaker wires or interconnects have special audible qualities, so you know where I'm coming from wen I say the Bennic NPEs should be just fine. Whatever you choose, they will be better and last longer than what's in there.

Kent

Thanks for some practical advice on "boutique" components. I share your philosophy re wires and components, also. I was astounded by the sheer volume of discussion on the board surrounding capacitors. Capacitors seem to perform based primarily on their actual capacitance (as measured) which can be affected by their age. That's simple enough. Many thanks to you and r_laski for your patient and sound advice (no pun intended)! Cheers - -M.

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>>I found single Solen capacitors at exactly the 120uF capacitance at Madisound. Seems a good way to go for not too much to avoid having to parallel others.<<

A single Solen cap is a very good way to go.

>>Also, the foam surrounds for my tweeters are in fairly good condition. Would you suggest I leave them alone for now or consider the felt surrounds offered by Vintage AR?<<

If the foam is not dried out and turning to dust, or, turned into a sticky, goo - leave them alone. I had to remove the tweeter foam on my AR-11s and I just left them "naked" like the earlier AR-11A's were.

>>Gee, I really appreciate everyone's help. I've listened to today's speaker technology on the market and I cannot find anything below $6,000 with my ears and preferences that compare to our AR's.<<

I know what you mean!!

Good Luck restoring your AR-11s

Rich

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Last year when I stumbled across a pair of 10 pi's (the later version), Ken Kantor indicated that the foam on the front of the tweeters was not a good idea (he did not elaborate). I removed the foam (which was crumbling anyway), but left the plastic sheet that was under the foam attached to the tweeter's front panel (it protects the leads that go to the voice coil, so you really do want to leave it in place, even if you do gently scratch off the old foam).

I have not recapped mine (I have the parts, I just haven't felt the drive to dive in with my soldering iron). Frankly, the sound is so good with the original parts, I'm hard pressed to justify changing anything. I do not drive mine hard (I run an old McIntosh amp, 75 watts a side, rarely too loud to talk over), in a small room like yours, and find them to sound more natural and "right" than anything I've heard (including everything from Quad electrostatics to Klipschorns to stacked Advents to Dahlquist DQ-10's). All things considered, a phenomenal design.

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Guest Mike Slate
>>I found single Solen capacitors at exactly the 120uF capacitance at Madisound. Seems a good way to go for not too much to avoid having to parallel others.<<

A single Solen cap is a very good way to go.

>>Also, the foam surrounds for my tweeters are in fairly good condition. Would you suggest I leave them alone for now or consider the felt surrounds offered by Vintage AR?<<

If the foam is not dried out and turning to dust, or, turned into a sticky, goo - leave them alone. I had to remove the tweeter foam on my AR-11s and I just left them "naked" like the earlier AR-11A's were.

>>Gee, I really appreciate everyone's help. I've listened to today's speaker technology on the market and I cannot find anything below $6,000 with my ears and preferences that compare to our AR's.<<

I know what you mean!!

Good Luck restoring your AR-11s

Rich

Thanks again, Rich. I removed the woofer from one of the AR-11's. The largest capacitor was indeed 120uf. It is in a silver can but it's covered with a plastic sleeve that felt tight yet flexible and appeared very clear. The plastic sleeve was not dried out. I could not see a manufacturer's name on it. The cap was held to the board in part by a cable tie of a ladder variety, like that which may have been loaded in an industrial gun. The resistors sit on very clean white glue; no sign of scorches. Smaller components were wrapped in batting. Larger pieces filled the cabinet. It too was very clean, white, and seemed to be in excellent condition. Lacking a VOM, capacitance meter or a bridge, I could not measure the cap. Interestingly, the aluminum rim of the woofer was sealed all around its edge against the cabinet with plummer's putty. I can only assume that the speaker repair shop in Memphis used this material to ensure an airtight seal. Based on what I saw, I suspect that these are still the OEM caps used by AR when they built the speaker. Any guess or your part? Tnx - -M.

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Guest Mike Slate
Mike,

Here is a picture of an original AR-11B crossover. If yours looks like this, its all original.

post-100657-1255981384.jpg

Based on your visual inspecton, I'd recommend you replace the caps (even though you can't measure them) and leave everything else alone.

Rich

Thanks for all your help, Rich. I learned a lot. Cheers - -M.

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