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Glitch

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  1. Glitch

    ADS L1590

    Tom, I thought that you might like to know that "your" L1590's are still going strong. I installed them as part of my main system when they first arrived. I regularly rotate speakers in-and-out in my secondary systems, but I cannot imagine doing so with the L1590's. The L1590's are my go-to speakers when I need a reference for how a speaker "should sound". I still have the original boxes. Yes, I know it is weird to mention this, but it somehow important to us "box guys" that will store the original packaging for decades. I've actually repurposed the boxes. For reference, a pair of L880's fit perfectly in a L1590 box for storage purposes. šŸ˜‰ I know it may be months (or years) before you see this, and possibly the same for me if you reply. Also, thanks for posting the pictures of the speakers on the dollies. I enjoyed seeing them. Glitch
  2. Glitch

    ADS L1590

    Better late then never? ? I just reread the entire thread. Does this add 1 to the counter? One thing I noticed is that the links to the .pdf files and many of the pictures are dead. Bummer.
  3. That's odd... Sure, it might be the last connector in existence for sale, but you might be the last guy in existence that needs one ? Good luck with your search!
  4. It has been some time since I did the phenolic tweeter comparisons. My recollection of the RT-6 is that it didn't do anything particularly bad. However, it didn't do anything remarkably good. I recall that it didn't seem to reach the higher frequencies as well as the PRT-8. Nor did it provide the classic CTS phenolic tweeter sound signature as well. My basic assumption is that the reason that people are buying the reproduction phenolics is that they are trying to reproduce the sound signature of a particular classic speaker. The PRT-8 also seemed to be built better with heavier metal for the basket and a bigger magnet. I liked the integrated grill of the RT-6 since this mimics the style of the drivers I was trying to replace. Unfortunately, the sound quality wasn't what I was looking for. I ended up buying a used pair of vintage/original CTS phenolics to complete the project.
  5. I bought a pair of the GRS PRT-8 mentioned above as part of a restoration project of a 70's era pair of speakers. One of the speakers had the factory original CTS tweeter. The other had a slightly different CTS tweeter that was replaced under warranty. There was enough of a mismatch between the two tweeters to motivate me to replace them with a new "matched pair". Unfortunately, I was not happy with the sound quality of the PRT-8. The original CTS phenolics tended to be a bit squawky. The PRT-8 is much more so. I found the PRT-8 to be harsher than every other of the vintage/original phenolic tweeters that I own. I can see why the PRT-8 gets good reviews. It is certainly a good match visually. It also exhibits the sonic character that most people associate with the original CTS phenolic (perhaps to a fault). I might have been happy with the PRT-8 if I had not done A/B testing against the originals. I also tried the RT-6 phenolic that PE sells. The PRT-8 is a better driver than the RT-6.
  6. Glitch

    ADS L1590

    Setting up a listening comparison between those two speakers would be a real treat. I have neither, so it could be a long while until I have the opportunity. Based on my experience with the L1590, L1290 and L880, I would think that you would be able to A/B your 3a's and L1290's and get a very good feel for how they stack up. The tricky part of the experiment might be getting the room setup right since each of those speakers would have a fairly different "ideal" spot in the room. I'm guessing that you already thought of this and is one of the reasons why you suggested the 3a to L980 comparison. (i.e. both would benefit from a similar setup position, etc.). The Stereophile Magazine article was a trip down memory lane. To me, it seems "right" that there weren't any ADS offerings on the list. I've never thought of ADS as one of those companies that was targeting the stereotypical audiophile personality. Sure, there were other companies on the list that are arguably similar in this regard. IMHO, there products were more revolutionary than anything ADS did. As big of an ADS fan as I am, I don't feel slighted at all by the list. Here are some relevant part numbers (from the ADS parts list) L880: tweeter 206-0117, mid 206-0211, woofer 206-0346 L880/2: tweeter 206-0117, mid 206-0215, woofer 206-0357 L1290: tweeter 206-0117, mid 206-0211, woofer 206-0349 L1290/2: tweeter 206-0117, mid 206-0215, woofer 206-0359 or 206-0360 L980: tweeter 206-0118, mid 206-0212, woofer 206-0347 L980/2: tweeter 206-0118, mid 206-0214, woofer 206-0353 L1590: tweeter 206-0119, mid 206-0213, woofer 206-0350 L1590/2: tweeter 206-0118, mid 206-0214, woofer 206-0361 I'm a bit surprised that drivers pattern on the L980/L1590 doesn't follow the same pattern as the L880/L1290. I wonder if the L980 was introduced "late" relative to the L1590? (i.e I expected that it, L980/1, would have a 206-0119 tweeter & 206-0213 mid)
  7. Glitch

    ADS L1590

    The L1590 has different tweeters, mids and woofers than the L1290. I assume that each one of the components in the L1590 is rated for more power, but can't find any data right now to back up my theory. I'm sure that I have data from the L1290 and L880 drivers somewhere on my computer. Unfortunately, I'm pretty thorough at testing and analyzing data, but usually not very good at documenting the results. If I found the data, it might not be clear what I actually tested. It all may be a moot point since I tested individual drivers from the L1290 and L880, but didn't disassemble the L1590 for individual driver testing. My comparisons between the L1290 and L1590 were done with the speakers side by side connected to a speaker selector switch. In the past, I've tried to run quantitative comparisons of overall speaker performance, but never obtained results that I thought I could trust. I typically end up doing qualitative evaluations (which may be too subjective to be useful to anyone else). I recall reading somewhere that the L1590 mids and tweeters had stronger magnets than the L1290. However, I can't recall where I read that. I've only experienced one ADS driver with a ferrofluid issue. The best way I can describe it is that the fluid "crusted over". The fluid under the crust seemed fine. I originally repaired the driver by cleaning out all of the dried fluid "chunks" and running the driver with the remaining fluid. I've since completely replaced the fluid (several times) in the course of my various experiments. I believe that improvements in imaging in my L1290 (and L880) were more from using matched driver pairs than anything else. I'd love to be able to repeat the driver matching experiment on the L1590s, but I don't have a suitable pool of spare parts to make it happen. Unfortunately, no. There are only a couple of ADS speakers that are on my watch list and the L980 is one of them.
  8. Could one use a MiniDSP programmed to match the frequency curve of the AR speaker? It seems the dynamic response would be different (i.e. impossible to match), but the general voicing character might be close enough to be believable.
  9. Glitch

    ADS L520

    Swapping woofers would tell you what you need to know. The woofers may (or may not) be difficult to remove from the cabinets. As a first step, you could disconnect one wire from the woofer (between the woofer and crossover) and repeat the "receiver test" again connecting directly to the woofer. This will eliminate the crossover from the test and saves the work of removing the woofer. Another possibility for debugging is to swap crossovers. All of the "all uppercase" era ADS speakers (i.e. ADS versus aDs or a/d/s) that I own use spade connectors to connect to the drivers. I'm a bit surprised by your comment about the connections being soldered. However, you never really know what you will find inside of a vintage speaker. Soldering is pretty easy and a worthwhile skill to have. Please post some pictures of what you have. It will make it easier for people to provide advice. As I said in my first reply, I haven't worked on that particular model. I'm making some guesses about what you have based on experience with other ADS speakers.
  10. Glitch

    ADS L520

    An ADS document lists the woofer part number as 206-0326 for speaker serial numbers 0 to 10199. For serial numbers 10200 and up, the part number is 206-0323. This seems odd since one would expect the "higher" number to be used in the newer speakers. Have you done any debugging to verify that the woofer is the actual problem? For example, check with a multimeter or swap woofers between speakers.
  11. Glitch

    ADS L520

    Congratulations on your purchase! I learned something new about the wood patterned vinyl finish on the early L520s. ADS also used a simulated wood finish on the L470s, even into the metal grill era. It sounds like you scored on the records. Some kinds of vinyl are better than others. I'd be interested in hearing your impressions (and seeing more pictures) once you get settled in with the speakers.
  12. Glitch

    ADS L520

    Disclaimer: I don't have first hand experience with the L520's. I do have a lot of experience with many of the other speakers in the ADS line. In general, it is hard to go wrong with ADS speakers as long as the drivers are original and working. The L520's use a tweeter that is common with a large number of other (highly regarded) speakers in the ADS line. All you need to look for is that the tweeters make noise and the sticky coating is in reasonable condition. The tweeters can/will collect dust, pet hair, etc., but as long as it is not excessive it doesn't affect the sound quality. The woofers are unique to the L520's. In general, ADS woofers aren't problematic. I'm almost 100% sure that the L520's use rubber surrounds. Just make sure there aren't holes in the cones or tears in the surrounds and you'll be fine. Rough cabinets are only as big of deal as you want to make it. As long as they maintain an air seal with the woofer you should have a good experience. Are the cabinets wood or black? Wood should be walnut veneer, not vinyl. The crossovers may be have NPE capacitors in the high frequency circuits. Speakers higher in the ADS pecking order usually have film capacitors that very rarely ever go bad. The NPEs that ADS uses usually don't go bad, but it would be worth investigating if you buy them. I have a pair of the L570's. These are the natural evolution of the L520's. These are very nice speakers. While they aren't as amazing as the ADS high end speakers, they will give you a reasonable feel for what the ADS community is raving about. I think that it is a pretty safe bet to buy the speakers at that price (as long as the drivers are good). I would try to talk the seller down a bit, but I always try to talk the seller down, even if it starts off as a great deal. If you don't like the speakers, you could likely get your money back out of them by parting them out. I think the biggest risk you are taking is that you will love them and put more time and money than what they are worth into the restoration. There is also the risk of total addiction. The L520's could be thought of as a gateway drug. Post some pictures if you can, I (and likely others) will be able to provide better advice on the condition of the actual speakers and prospective pitfalls.
  13. Glitch

    ADS L1590

    Tom, Yes, I did spend some time comparing the L1590s and L1290s. I found the speakers to be very similar in the overlapping frequency bands. For this comparison, I used a Crown pro amp and used the built-in DSP to filter off the lower frequencies (where the L1590s have a clear advantage). This allowed me to more easily evaluate the mid, tweeter and crossover performance. I found overall tonality/voicing of the speakers to be remarkably consistent. I think the biggest difference between the two models is in the "attack" of sharp sounds like a hard snare hit. For these kinds of sounds, the L1590s seem not only faster, but also better damped. Both models exhibit the celebrated ADS sparkle. Both speakers reached highs that are beyond my hearing range. I didnā€™t notice any difference in the lower mid-range at the mid-woofer crossover frequency. I replaced the L1290s in my main system with the L1590s. I put them in the same location. The overall imaging was slightly better with the L1590s. I found the need to use an acoustic panel with the L1290s to tame some upper mid-range harshness. The L1590s also benefited similarly from the panel at the same location. I believe this confirms my theory that the problem lies in the room geometry and speaker placement. Unfortunately, my speaker placement is more governed by WAF than acoustic optimization. The most dramatic difference between the speakers is in the lower frequencies. The L1290s simply donā€™t go as low. I used a pair of subwoofers with the L1290s to extend the ultra-low frequencies. I was very happy with how well this worked. I am using the same subs with the L1590s. I had a much harder time integrating the subs with the L1590s. The subs ended up in a very different configuration than with the L1290s. I could live without the subs with the L1590s. I moved the L1290s into my basement workshop and added them to what we affectionately call ā€œThe Pileā€. The Pile contains many of the speakers that Iā€™m working on. They are all connected to a speaker switch where I can run A-B comparisons as Iā€™m tweaking things. I decided to rework the mids and tweeters in the L1290s. I recently did the same to a pair of L880s and a set of spare mids and tweeters that I had on hand. I replaced the ferrofluid and realigned the voice coils. I performed measurements on all of these drivers and used the data to create matched pairs. Matching the drivers greatly improved the imaging of both the L1290s and L880s. Both of these speakers are Series 2 and use the same mids and tweeters. Iā€™m still doing experiments on these where Iā€™m varying the ferrofluid viscosity. The jury is still out on which combination I prefer the most. The experiments are a slow process. I hope to have this nailed down by summertime. I think that I have been able to improve the ā€œattackā€ of the L1290s to be more like the L1590s with the tweaks. I suspect that the L1290s may now outperform the L1590s in imaging performance. I wonā€™t really know how successful the changes were until I move the L1290s back upstairs and do direct A-B comparisons. I recently picked up a pair of PA1 amps. One of the amps was dead when I bought it. I was able to repair the broken one and went through both amps to ensure that everything is working well. I have the PA1s installed in the L1290s now. Glitch
  14. Glitch

    ADS L730 Mods

    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
  15. Glitch

    ADS L730 Mods

    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.
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