ADS L730 Mods

[jaykay3]

Hello! Anyone have any information on modifying L730 or similar? Worth using some modern drivers, etc? Any information will be hugely appreciated! Thanks. jk3

[Glitch]

What are you trying to accomplish with the modification? 

A properly working L730 should be a very nice sounding speaker.  Some of the newer ADS drivers will be more linear (and bolt right in), but would likely require crossover modifications.  Of course, you could install some brand new drivers and make it work.  I don't know of any modern mid/tweeters that have the same mounting method (i.e. rectangular plate).  The modified speaker would likely have a Frankenspeaker look to it.

[jaykay3]

Thanks Glitch.

 

To clarify - I LOVE the sound of these. Just picked them up on the cheap cheap and they are in perfect condition top to bottom drivers to  My dad had ADS when I was growing up, and the sound is something i'll always be fond of. 

 

I just really want to make sure i am getting the most out of these. Someone told me yesterday that having the crossovers rebuilt with the most modern caps/etc. will make a big difference. 

[JKent]

Welcome Jaykay3

A disclaimer: I'm not an ADS expert. But here is some info: http://stereonomono.blogspot.com/2012/12/ads-l730.html

My advice, FWIW: If you LOVE the speakers do NOT modify them! They were carefully designed by engineers and computers, so just slapping in new drivers, no matter how good (or expensive) will alter the sound. These speakers are known for their accuracy, so why mess with that?

OTOH, they are from ~1980 and assuming they have electrolytic capacitors in the crossovers, those "could" be out of spec by now. I get a little nervous when I hear 

1 hour ago, jaykay3 said:

Someone told me yesterday that having the crossovers rebuilt with the most modern caps/etc. will make a big difference. 

Capacitors maybe. Nothing else. One poor soul on the AR thread had his vintage AR speakers "crossovers rebuilt with the most modern caps/etc" and yes--it DID make a "big difference"--it RUINED them! 

So. If they sound good enjoy them! If you feel comfortable poking around inside with a soldering iron go ahead and replace the old capacitors with some mylar or other film caps and/or non-polar electrolytics but leave everything else alone.

-Kent

PS: I was looking for info on the crossovers and found an old ad for some for sale. They've been sold but it looks like the whole crossover is fastened to the speaker terminal plate and is very easily removed. No need to pull the woofer. But it's a PCB, pretty tightly packed. I couldn't see the caps but I don't think I'd mess with it.

Speaking of woofers. Do these have foam woofer surrounds? If so, that's where you should make repairs.

[Glitch]

The components that ADS used in the crossovers were very good.  Most of the capacitors in your crossover are of a type that does not degrade over time.  Your crossovers do  have one large electrolytic capacitor.  Some brands of electrolytic capacitors will drift from their specified values over time.  That particular electrolytic is not on the main signal path and is part of the low pass circuit for the woofer.  As such, any drift in its value would have a secondary effect on the sound quality.  I've measured a handful of these capacitors from similar ADS models and have not found any to be out of specification.  The remainder of the components on the board (i.e. inductors, resistors, etc.) rarely go bad.  

It is unlikely that your crossovers are bad, or even could be improved significantly.  I've run experiments of original ADS crossovers versus ones that I've modified with expensive capacitors (>$100 per crossover).  I had to run carefully set up A to B tests and find specific snippets of songs to hear any difference.  Even then, I'm not really sure that there really was a difference or that any difference I thought I heard was an improvement. 

I think that is worth the effort to pull out the crossovers, remove the components and measure them to verify that they are in specification.  Almost always, I end up reassembling the crossover exactly as it was originally.  It is kind of a waste of time, but I do get the peace of mind that i "know" the crossover is working per the original design.

I believe that the tweeter and midrange on the L730's are before ADS started using ferrofluid.  As such, you don't have to worry about the ferrofluid be degraded.  About the most you could do is carefully pick off any dust or pet hair with a pair of tweezers.  I'd only go after anything that is loosely stuck in the sticky coating.  Leave anything that is deeply embedded alone.  You will do more harm than good trying to remove it.  This exercise won't make the speakers sound any better, but will improve the way they look.

There is not much you can do with the woofer other than rotate it 180 degrees to address the possibility of spider sag.  I don't do this unless I have the woofers out for some other reason.  Unless you are are very careful, and a bit lucky, you may damage the cabinet.  I don't think that the risk is worth the reward.

The one place that you may be able to make some "changes in sound" is by adding damping and internal bracing to the cabinets.  This will make the speakers sound more "point source".  I wouldn't do this If you like a more "ambient" sound.  When I've experimented with this kind of modification, I do it in such a way that the mod is reversible in case I don't like the results.  I've had a few pairs that I kept the cabinet mods.  I won't go so far to say that they are better.  They do better match my sonic preferences.

I've also experimented with changing the stuffing.  Most of the time, after days of experimenting, I end up putting the original stuffing back in the speaker.

ADS, especially in the era of your L730's, did a nice job of voicing their speakers.  If you like the sound, do what you can to ensure that they are in specification, then just enjoy them.  If you mess with them too much, you may loose a bit of the ADS magic.

Glitch

[jaykay3]

1 hour ago, JKent said:

Very cool. My name is JKent as well - does your first name also happen to be John?

Thanks to you and Glitch for sound advice! Looks like i'm just going to put some wood polish on the beautiful cabinets and call it a day! Cheers! Kent

[JKent]

6 hours ago, jaykay3 said:

Very cool. My name is JKent as well - does your first name also happen to be John?

Yeah. Don't know why my parents (and yours) put my "first" name in the middle but yes--John Kent aka J.K., J Kent, etc.  Odd to stumble across another J. Kent but IIRC there was one on another forum. It's a real pain:

• Got me into trouble at the DMV,
• my young neighbor was collecting my mail and asked "who's John?",
• I was in a social group and asked an acquaintance to Air Drop a picture to my iPhone and she said "I don't see you. Just 'John's iPhone'". 

But back on topic: I'd say Glitch really knows these speaker (I don't) so the best take-away I think is: Just enjoy them!

If you want to get into a crazy hobby of tearing into old speakers to bringing them back to life (like most of us here) you'll have to go with something a bit older, like AR or KLH.

-Kent

[GD70]

The only thing I would recommend is sending the mids and tweeters to Richard So, a former ADS employee who bought all the parts inventory when ADS closed its doors. His prices are very reasonable, and they come back like brand new! After 30+ years, they may not sound as new. I did mine on my 910's, mostly for preservation, and peace of mind knowing they are good for another 30 years. Parts will eventually run out! They sounded great before the rebuild, and even better after. Next I will most likely send the mids and tweeters from my L980's. They sound fantastic, but again, for preservation, fresh ferro fluid. How many speaker owners have the option of getting rebuilt drivers with oem parts by an ex employee? Very few.

Glenn

[Gerry S]

As a loudspeaker designer (retired), I wouldn't do "mods" for ADS loudspeakers. As is, they are well built and well designed. Unless you possess the technical knowhow, as well as access to necessary test equipment, ANY change you make will most likely just ALTER system performance; NOT "improve" it. These are loudspeaker SYSTEMS, where each driver is meant to work with their associated drivers, and in that particular enclosure.  If you change/substitute just ONE driver (woofer, midrange, tweeter), you've essentially changed the whole system (probably for the worst). Even if a driver swap is miraculously "successful", you would have to do the same for both speaker systems to get reasonably matched "stereo performance".

I believe that "modifying" any loudspeaker system for personal preference can be fun. But if the mods are made to a "classic", that product is no longer a classic.

[DavidDru]

Just use them as is.  If they don't sound good, sell them off.  Unless they have been mistreated, they should be fine.

[audiofreak]

One of my best friends is a retired ADS sales and warranty service center owner and service manager, his experience in servicing and selling ads is he has never found a service issue with ADS xovers! Drivers blown yes but never a bad cap or board. So it's possible you have the first but highly unlikely! Check drivers, connections, wiring, before xovers.

[Adamo0926]

Saw this topic and wanted to ask a question.  I have a pair of ADS L730s and have always been curious if the mid-range driver from the ADS L810 would be compatible with the L730s.  It looks as though the face plate would fit right into the opening of the L730s, the only difference being that the L810 has the larger dome midrange.  I think the L880 also has the same midrange driver as the L810.  Essentially if the L810 midrange is compatible with the L730, it would be kind of like turning my L730s into L880s.

 

[Denny]

Question for someone. I have a pair of L730's and the fuses on the back need replaced the two I took out are not the same does anyone know what fuses to use ? Thanks in advance.