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AR90 10 inch woofer replacement

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My amplifier's right channel went south and took out both woofers. The voice coil resistance check shows they are burned out. What are my options?

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One wire in each speaker from the voice coil to the terminal strip somehow became disconnected. Voice coil is not rubbing.

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Yes, but it leaves it a bit tighter than I care for.

I'm considering adding a pig tail to the end of the wire and putting a loop in the additional wire to improve flexibility.

What baffles me is why the same wire on both 10 inch speakers came loose in the first place.

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Without seeing pics to better describe the situation, the first thought would be, as DavidR has already suggested, to find a way to reconnect the severed wire. If it requires additional length to accommodate movement, you may need to figure out how best to fabricate and attach a small extension segment with possibly two solder joints per wire.   

 

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Are these 4 ohm or 8 ohm drivers? For the life of me, I thought these were 8 ohm speakers but they measure 4 each. And yes, these are the originals with the square magnet.

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They are 8 ohm drivers (AR# 200031   10" Woofer) and should measure around 6.5 to 7 ohms DCR.

 

Mine have a square magnet also.

 

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6 hours ago, DavidR said:

They are 8 ohm drivers (AR# 200031   10" Woofer) and should measure around 6.5 to 7 ohms DCR.

 

Mine have a square magnet also.

 

I checked one speaker's resistance and it initially read 3 ohm. Moving the voice coil and letting it settle, it read 1.5. Moving it a bit more, it settled around 5 ohm and briefly, it read 0. The voice coil is not shorted to the frame nor is there a rubbing sound. This would make sense to me if the voice coil was rubbing.

My original thinking was the amplifier failed due to age and two wrong transistors in the circuit. The circuit design uses matching PNP to NPN devices. The wrong parts specs were close but still off. I'm beginning to think it was the speakers that caused the amp to fail. 

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watch ebay for used originals.  FS and QTS on this is way too high.  I'd use 2ax woofers before this...as far as a new woofer that is closest in specs to a 10" AR woofer, this is probably your best bet:

http://meniscusaudio.com/eclipse-w1038r-p-567.html

or this one from human speakers

http://www.humanspeakers.com/diy/parts/031.htm

 

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Based on your description of the readings I'd say the vc is cooked. A while back I bought a pair of AR94 just for the drivers. One of the 8" woofers did the same thing and then stopped giving a reading - cooked.

I like michiganpat's idea about looking for originals on eBay or an AR2 woofer.

You might also check with RoyC to see if he can replace the vc.

Good Luck

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Excellent feedback from the both of you. Thank you.

If the VC is cooked, and given the VC unsoldered itself from it's terminal strip coupled with something inside my amp deciding to glow like a light bulb the day it died, the VC is likely cooked. The channel has two 5 amp fuses on the +/-100 VDC rails. Both blew.

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7 hours ago, michiganpat said:

watch ebay for used originals.  FS and QTS on this is way too high.  I'd use 2ax woofers before this...as far as a new woofer that is closest in specs to a 10" AR woofer, this is probably your best bet:

http://meniscusaudio.com/eclipse-w1038r-p-567.html

or this one from human speakers

http://www.humanspeakers.com/diy/parts/031.htm

 

 



Please correct me if I am wrong.

 

Looking at the specs on the two suggested replacements, I'm thinking the speaker from humanspeakers is a closer match.

I also found these on eBay:

http://www.ebay.com/itm/Acoustic-Research-AR-2ax-Woofer-speaker-driver-34-/272404005542?hash=item3f6c8b42a6:g:kjoAAOSwpLNX9sXV

http://www.ebay.com/itm/AR-2ax-Woofer-Tested-and-Working-Foam-is-Good-Acoustic-Research-/322274307879?hash=item4b090baf27:g:A9cAAOSwCGVX6d49

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I was looking at the Eclipse woofer for a project using some bare 2ax cabinets I picked up for $10.  it actually calculates out to having a very similar low end response as a 2ax woofer (IIRC Qb was around .8-.85, with an F3 ~40hz and F10 was in the mid 20's).  what is the internal volume of the 90?  using the 2ax's internal volume, the Human woofer actually ends up being a little underdamped (Qb~ .670) with a 38hz F3 and F10 at about 19.5hz.....for originality, I'd see if I can find someone who could replace the voice coils while reusing the original cones on your drivers....Roy or someone else might have a better idea as to whether or not the Alcino 10" 2ax woofers would be a good match to the ferrite magnet 10" woofers in the 90's, but I would think so....

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Someone else needs to respond with the internal volume for the AR90. I can't find it in the specs and I've no idea how to compensate for the internal packing in the cabinet.

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I have no experience with this speaker model, but I did locate some AR literature (written in French) that notes that the AR-90 cabinet volume is 90 liters. (By comparison, the AR-9 is noted as 120 liters, and the AR-91/92 is 46.8 liters.)

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5 hours ago, michiganpat said:

for originality, I'd see if I can find someone who could replace the voice coils while reusing the original cones on your drivers

You may want to contact Bill LeGall. http://www.millersound.net/

If anyone can do it he can.

-Kent

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Also, the stuffing method used in the AR-90 cabinet is similar to that used in the AR-9; while the AR-91 is filled with stuffing, the 9 and 90 just have it in the upper section of the enclosure, as described in the technical drawings.

ar90a.JPG

ar90b.JPG

ar90c.JPG

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AR-Pro,

That drawing above, is there a similar drawing showing more of the stuffing configuration and call-outs?  I am looking for similar for inside the mid woofer box.  mine seem to just have stuffing stuffed into it and am wondering if that is correct.

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