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Renewed ADS L710's

Ed Bailer

Ed Bailer

New Member
Some time back, I purchased a pair of ADS L710's on eBay for $200. Not surprisingly, the tweeters and midranges were way past their prime. Last month, I finally sent them off to Richard So (adsspeakerservice.com, ads_speakers@yahoo.com), an original employee of ADS - he is the man to restore parts and make repairs for many ADS models. I sent off my tweeters and midranges to him and for the total sum of $256 including his shipping cost, they came back looking like new (photos to follow). He's found a way to rebuild them without the magnetic ferro-fluid ADS used to dissipate heat, but over time that ferro-fluid breaks down and the drivers get dull and produce dull sound.

Mr. So's workmanship is stellar. My old faceplates look new, as are the leads - the new diaphragms have a bronze like color - very attractive. And best of all, the SOUND! If you like bright sounding (imagine accurately reproduced hi-hat cymbals, brass instruments and other such sounds with rich transients), yet relatively neutral speakers with great dispersion and good bass in a large bookshelf format (they look great on stands, too), these are fantastic! That large 2 inch dome midrange is amazing! It's operating frequency range is 550-4000 Hz which roughly corresponds to the upper three octaves of a piano. The two 7" woofers cover 25-550 Hz and the 0.75 inch dome tweeters cover 4000-30,000 Hz. The L710's specs: Frequency response 40-23,000 Hz (±3 dB), 25-30,000 Hz (±5 dB); Impedance: 6 Ohms nominal, 4 Ohms minimum; Nominal power rating: 75 W; Musical peak power rating: 150 W; Recommended amplifier power: 15 W RMS minimum, 150 W RMS maximum; Efficiency: 92 dB SPL (at 1 Watt RMS input at 1 meter); Crossover frequencies: 550 & 4000 Hz: slope-12 dB/octave. I bet you could find a review by Stereo Review's Julian Hirsch for an in-depth exploration of these or other ADS speakers somewhere. These speakers live up to the hype in my opinion. These have been on my bucket list for ages and now I've got a great sounding pair. I've un-dented the perforated metal grills and will soon paint the grills black. The cabinets had a tough life, apparently, but I hope to make them look appealing again.

My actual point is, If you've got a pair of ADS speakers with drivers that need repair, visit Mr. So's website and check him out. There's no one more qualified to service this brand since he used to assemble them when they were new. For an average price per driver around $50/ea, it's well worth the investment. After Mr. So's repair, my L710's sound just like new, and I heard these new, when the first came out back in the '70's. With his repair, these should perform flawlessly for the next forty years.
 
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L710 did not have ferrofluid. I believe Richard rebuilds to be like new. Ferrofluid came later in the ADS timeline of drivers.
Ferrofluid is a serious damping fluid so when it is used the driver is designed to use it and not using it will not provide proper sound quality and might make the voice coil much easier to burn.

ADS reviews in period magazines can be found at www.worldradiohistory.com. Lots of magazines to search through but the Audio, High Fidelity and Stereo Review are the three that were popular audio mags and would have the reviews. These are about 1/3 down the page with a light pink band marking the category. I don't know if the version you have, later metal grilles would have been reviewed and don't even know if the earlier cloth grilled versions were reviewed. I know I like mine just fine and in great working shape. Be nice to compare them to a fresh rebuild pair.

Yes, Richard So is a valuable resource for ads owners needing driver service.
 
I don't have L710's, but I'm a big ADS fan - L300C's, second gen L520's, L780/2's, L1090/2's, and M12's (replacement for L1290's). The drivers in the M12's had been rebuilt by Richard a few months before I bought them, and they appear like new. More importantly, they sound wonderful. They are a bit big in their current location, so I'll try the L1090's in their place, once I have Richard take care of the drivers. They are all great speakers, and Richard really does do wonderful work.
 
I have L710's and love them. I also have 1530's, and those will eventually have their drivers rebuilt by Richard So. Love the midrange domes.
 
Ed Bailer said:
Some time back, I purchased a pair of ADS L710's on eBay for $200. Not surprisingly, the tweeters and midranges were way past their prime. Last month, I finally sent them off to Richard So (adsspeakerservice.com, ads_speakers@yahoo.com), an original employee of ADS - he is the man to restore parts and make repairs for many ADS models. I sent off my tweeters and midranges to him and for the total sum of $256 including his shipping cost, they came back looking like new (photos to follow). He's found a way to rebuild them without the magnetic ferro-fluid ADS used to dissipate heat, but over time that ferro-fluid breaks down and the drivers get dull and produce dull sound.

Mr. So's workmanship is stellar. My old faceplates look new, as are the leads - the new diaphragms have a bronze like color - very attractive. And best of all, the SOUND! If you like bright sounding (imagine accurately reproduced hi-hat cymbals, brass instruments and other such sounds with rich transients), yet relatively neutral speakers with great dispersion and good bass in a large bookshelf format (they look great on stands, too), these are fantastic! That large 2 inch dome midrange is amazing! It's operating frequency range is 550-4000 Hz which roughly corresponds to the upper three octaves of a piano. The two 7" woofers cover 25-550 Hz and the 0.75 inch dome tweeters cover 4000-30,000 Hz. The L710's specs: Frequency response 40-23,000 Hz (±3 dB), 25-30,000 Hz (±5 dB); Impedance: 6 Ohms nominal, 4 Ohms minimum; Nominal power rating: 75 W; Musical peak power rating: 150 W; Recommended amplifier power: 15 W RMS minimum, 150 W RMS maximum; Efficiency: 92 dB SPL (at 1 Watt RMS input at 1 meter); Crossover frequencies: 550 & 4000 Hz: slope-12 dB/octave. I bet you could find a review by Stereo Review's Julian Hirsch for an in-depth exploration of these or other ADS speakers somewhere. These speakers live up to the hype in my opinion. These have been on my bucket list for ages and now I've got a great sounding pair. I've un-dented the perforated metal grills and will soon paint the grills black. The cabinets had a tough life, apparently, but I hope to make them look appealing again.

My actual point is, If you've got a pair of ADS speakers with drivers that need repair, visit Mr. So's website and check him out. There's no one more qualified to service this brand since he used to assemble them when they were new. For an average price per driver around $50/ea, it's well worth the investment. After Mr. So's repair, my L710's sound just like new, and I heard these new, when the first came out back in the '70's. With his repair, these should perform flawlessly for the next forty years.
Click to expand...


Hi, I just picked up a pair of L710s and am trying to get the crossover/back plate off. Do you know if it is glued? I am a newbie, so any threads would be helpful. I will try to repair what I can and then send what I cannot to Mr. So.
 

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tdksa90 said:
I will try to repair what I can
Click to expand...
What needs to be repaired?

Woofers should be in separate cabinet sections so pull the woofer that will access the back panel and give the crossover/input cup a push.

Check the woofers for rust between the surround and the basket leading to glue release and a place for the cabinet to vent. Don't worry about the crap on the sticky domes, more damage than cleaning isn't a good thing to do.

Grilles should massage back into shape if you got them.
 
Wow, while you were replying I was doing exactly that. The tweeter in one speaker (I have only looked at one so far) is not functioning. All other drivers seem fine. Rubber surrounds are great. Whole speaker seems to have been exposed to moisture. I popped the crossover plate out finally, it is not glued. I put both fuses in and ensured they are not blown. They seem to have no effect. Still researching. Thanks for the sticky dome advice. Taken.
 

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OK, I am back. I have tested both speakers. Here is the rundown: Very dusty, cabinets are beat up a little, one corner is chewed but otherwise restorable. Will be fun to lightly sand and oil. Drivers: all 4 woofers seem to be working. 2 bad tweeters, one bad midrange (I can see the broken wire on the front of that midrange). I do not have the budget to send drivers to Mr. So. I am thinking about rebuilding the tweeters myself using new silk domes. Anyone done this/have advice? If the cabinets were nicer, I may consider sending for repair, but these are pretty trashed and I have no room to keep them anyway, I just cannot resist a challenge. I have done refoaming several times but never rebuilt a tweeter.
 
Hi it's me again. Do these capacitors look shot? Or is that white stuff supposed to be there? I did a little Googling but did not find exactly this.

I was able to fix one of the mid-ranges by soldering the gossamer wire with some thin wire. It's a bit of a hack but at least it works. I've ordered new domes for the tweeters and I will try and fix those myself. I'm getting the ones off of eBay, which I'm sure is blasphemous to some folks but like I said these speakers are basket cases.
 

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Those are sand-filled resistors, and they don't look to be in very good shape. I'd replace them personally.

The capacitors in that crossover are either rectangular plastic-looking blocks, or the black round capacitors. The rectangular ones are film caps and unlikely to need replacement in terms of repair, although some people like to change them to impact the sonics... but IMO you can ignore those, they'll work fine. The black electrolytic caps may have aged a bit, though.

Personally I'd replace those resistors, get the HF drivers back in good nick, and listen to them before worrying about other parts to swap out.

John
 
I have another update if anyone's interested. I picked up what I believe to be a single ADS L400 that someone painted white. Had it been a pair I might have restored it back to its original blonde wood. It seems that it was walnut on the interior and blonde on the exterior. The blonde is what was painted over in white.
I cannibalized the tweeter and put it into my L710. It sounds incredible.
I tossed the painted box in the trash which killed me, but I accumulate too much stuff. It was so well made. I kept the woofer and have it listed on eBay for sale, since all of my woofers work. Now thinking about this I wish I had a set of L400s instead since my listening space is so small.
 
Hey, everyone, forgive me if this is not in the right spot. I am in SF Bay Area and wanted to offer my a/d/s L710 speakers free to anyone who may want them. Too heavy to ship, soooo, come and get them.
All woofers, crossover, etc are original, photos are currently on SF craigslist. one tweeter is rebuilt (by me), one tweeter came from the L400 mentioned in this thread. They are just too big for my space. PM me and come get them in time for the holiday.
i also have the woofer from the L400 and the other rebuilt tweeter you can have. Moving on to other projects.
 
Gone
tdksa90 said:
Hey, everyone, forgive me if this is not in the right spot. I am in SF Bay Area and wanted to offer my a/d/s L710 speakers free to anyone who may want them. Too heavy to ship, soooo, come and get them.
All woofers, crossover, etc are original, photos are currently on SF craigslist. one tweeter is rebuilt (by me), one tweeter came from the L400 mentioned in this thread. They are just too big for my space. PM me and come get them in time for the holiday.
i also have the woofer from the L400 and the other rebuilt tweeter you can have. Moving on to other projects.
Click to expand...
Gone
 
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