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  1. #1
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    A soon-to-be-performed Dahlquist repair

    I've recently posted this information elsewhere, but I think it's just too good not to do so here as well.

    Most of you familiar with my previous posts know that I own Dahlquist DQ-10's as well as B&W 802F Specials. Despite the retail price of the B&W's being five times that of the DQ-10's, in my current listening room, and with my current associated equipment, I prefer the DQ-10's by a considerable margin.

    Unfortunately, the mid bass driver in one of the speakers is defective, and the supertweeter in the same speaker is dead. I spent over $300 to have the regular woofers in both speakers rebuilt by Regnar a few years back, and while I've been happy with their results, there are many who think I was out of my mind to have spent so much on what's basically an Advent woofer (Regnar claims several important differences between the two, but I'll leave that issue up to them).

    The mid bass driver in the DQ-10 is no longer manufactured, and the only way to repair it is to send it to Regnar for a rebuild which costs almost the same as that for the much larger woofer - about $150. Regnar has the piezo supertweeter for sale at about $26.00.

    I did an online search for replacement Dahlquist drivers and came across a Dayton RS125S-8 5" woofer that at least one poster feels is better than the mid bass driver in the DQ-10. The Dayton appears to be solidly built, especially in comparison to the stamped frame of the original driver, and best of all costs only $27.22! Not to have a mismatch in the two speakers I ordered two of them, and the entire order, including shipping, came to only $64.77 - still less than half the price of a rebuild of one driver by Regnar.

    The piezo supertweeter in the DQ-10 has long been a subject of scorn and ridicule by aduiophiles. It's a very cheap device, with a characteristically "spitty" and abrasive sound, but, according to Jon Dahlquist, since it doesn't even start to work in the DQ-10 until 12,000HZ, most people would never be able to tell the difference between it and a far costlier driver. After the many years of listening to, and thoroughly enjoying my DQ-10's, I have to agree with Jon.

    Motorola used to make the piezo device, then CTS, and now it's made in China. At Regnar, "original" replacment piezos (Motorolas, I would assume) sell for $26.00. At Parts Express, where I ordered the Dayton woofers, it sells for an astonishingly low $1.44!! At that price, how could I possibly afford not to give it a try?

    So, now, instead of paying over $150 for a rebuilt woofer, and $26 for a replacement supertweeter, I've paid less than half of that for four new drivers to be installed in my DQ-10's. I'll be out of town for a few days and over the upcoming weekend, but I'll set about immediately installing the drivers upon my return home, and will happily report on my findings.

    Let's hope this was worth the modest expenditure, and if it isn't, I can get my money back from Parts Express. All in all, a "win/win" combination, wouldn't you say?

  2. #2
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by emaidel
    I did an online search for replacement Dahlquist drivers and came across a Dayton RS125S-8 5" woofer that at least one poster feels is better than the mid bass driver in the DQ-10. The Dayton appears to be solidly built, especially in comparison to the stamped frame of the original driver, and best of all costs only $27.22!
    That should work fine as there was nothing particularly special about the original.

    Quote Originally Posted by emaidel
    The piezo supertweeter in the DQ-10 has long been a subject of scorn and ridicule by aduiophiles. It's a very cheap device, with a characteristically "spitty" and abrasive sound, but, according to Jon Dahlquist, since it doesn't even start to work in the DQ-10 until 12,000HZ, most people would never be able to tell the difference between it and a far costlier driver.
    Primarily because most applications use them at far lower frequencies where their abrasive nature is more apparent. I've heard them used on some sound reinforcement speakers that sounded positively horrible. When I used to work for a Dahlquist dealer, there were many folks who simply disabled theirs. You'll note that newer versions such as the DQ-20 abandoned using the piezo. You'd be hard pressed to find a single serious speaker today that uses one, regardless of the crossover point.

    Good luck on your updates. The DQ-10 was always an excellent speaker. We had one customer who had a stacked double pair.

    rw

  3. #3
    Forum Regular audio amateur's Avatar
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    Congrats on finding a replacement, but how is the dayton compatible?

  4. #4
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    Quote Originally Posted by audio amateur
    Congrats on finding a replacement, but how is the dayton compatible?
    That remains to be seen. While a poster at the Parts Express website claims that these drivers are superior to the original ones, I'll have to decide for myself once I install them. From the photos, they look like they're better drivers, but until I see them in the flesh, that too remains to be determined.

  5. #5
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    Quote Originally Posted by E-Stat
    That should work fine as there was nothing particularly special about the original.


    Primarily because most applications use them at far lower frequencies where their abrasive nature is more apparent. I've heard them used on some sound reinforcement speakers that sounded positively horrible. When I used to work for a Dahlquist dealer, there were many folks who simply disabled theirs. You'll note that newer versions such as the DQ-20 abandoned using the piezo. You'd be hard pressed to find a single serious speaker today that uses one, regardless of the crossover point.

    Good luck on your updates. The DQ-10 was always an excellent speaker. We had one customer who had a stacked double pair.

    rw
    The truth is that none of the drivers in the DQ-10 was special. The woofer, arguably the identical woofer used in the Large Advent had at least that to its credit, but is a rather ordinary, paper cone/foam surround 10 incher with a magnet of only fair to middling weight. The "magic" of the DQ-10 has always been the crossover network that somehow took five ho-hum and even downright "lousy" drivers, such as the Piezo tweeter, and made the combination work so splendidly. The fact that I so prefer the DQ-10's to the far costlier B&W speakers I own says it all: while the 802F Specials use very expensive drivers, with heavy magnets and equally heavy cast aluminum baskets (as opposed to the cheaper, stamped variety), and have a crossover network that at least looks more substantial than that in the DQ-10, the Dahlquists all but wipe the floor with the 802's, at least in my listening room and with my associated equipment. I just wish they werent so big!

    I once was a partner in a manufacturer's rep firm along with a fellow who had stacked Dahlquists at one time, and didn't even realize that there were Piezos in them! With the grilles off, if I place my hand over the regular tweeter, I can hear that the piezos are working, but not much comes out of them. Covering up the piezo with my hand makes a slight, and almost imperceptibe difference. As long as I still like the overall sound of the system, I'll likely leave them in place, though I too knew of many people who disconnected them immediately after purchasing a pair of DQ-10's, or replaced them with far costlier drivers.

    Someone elsewhere made a comment about those who "modify" DQ-10's, regardless of whether or not the modification made the speakers better: once one starts tinkering around, and replacing drivers with other than those originally specified, the result, no matter how it sounds, is something other than a Dahlquist DQ-10. Interesting point, no?

  6. #6
    Shostakovich fan Feanor's Avatar
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    No reason to doubt, but

    Quote Originally Posted by emaidel
    That remains to be seen. While a poster at the Parts Express website claims that these drivers are superior to the original ones, I'll have to decide for myself once I install them. From the photos, they look like they're better drivers, but until I see them in the flesh, that too remains to be determined.
    I don't think you need to doubt that the PA Reference speakers are very good, however if their parameters are significantly different from the original, the results won't be good without crossover modifications. I see that the 5" Reference comes in both 4 and 8 ohm versions; other parms are important too.

  7. #7
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    Quote Originally Posted by Feanor
    I don't think you need to doubt that the PA Reference speakers are very good, however if their parameters are significantly different from the original, the results won't be good without crossover modifications. I see that the 5" Reference comes in both 4 and 8 ohm versions; other parms are important too.
    Point taken. Those that I ordered are 8 ohms, but as I have no way to determine their efficiency (amongst other characteristics) as compared to the stock driver, I just have to wait until they arrive and I install them to see if they'll work well. Fortunately, I can return them to Parts Express in the event they don't. Then, I guess, I'll be stuck paying Regnar their very high cost (over $150) to rebuild a relatively ordinary, initially inexpensive driver. Moreover, I'll likely have to have both midbass drivers rebuilt, as since one crapped out, it's very likely the other one will too. If that's the case, then I will have wound up paying more to repair the DQ-10's (woofers and midbass drivers) than I paid for the speakers themselves, having purchased them at an industry-insider's customary discount of 50% off list, which at the time was $500 per speaker.

  8. #8
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    Quote Originally Posted by emaidel
    Then, I guess, I'll be stuck paying Regnar their very high cost (over $150) to rebuild a relatively ordinary, initially inexpensive driver. Moreover, I'll likely have to have both midbass drivers rebuilt, as since one crapped out, it's very likely the other one will too. If that's the case, then I will have wound up paying more to repair the DQ-10's (woofers and midbass drivers) than I paid for the speakers themselves, having purchased them at an industry-insider's customary discount of 50% off list, which at the time was $500 per speaker.
    Perhaps it's time to look for some new speakers?

  9. #9
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    Quote Originally Posted by audio amateur
    Perhaps it's time to look for some new speakers?
    I'm retired and on a fixed income watching as my IRA and annuitites plummet daily. New speakers? Not likely. Then again, if a rich relative I've never known existed suddenly dies and leaves me a fortune, I'll happily start looking!

  10. #10
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by emaidel
    ...once one starts tinkering around, and replacing drivers with other than those originally specified, the result, no matter how it sounds, is something other than a Dahlquist DQ-10. Interesting point, no?
    True, but we'll never know how Jon D. would have updated them had he lived longer. As for me, I prefer my modified Double Advents to their original self since they improved an already good product. I would like to think that Henry K would approve of the subtle enhancements. Sometimes a designer is not fully aware of what can be done with his creation. While I have the greatest respect for Dr. West of Sound Lab (I've had the pleasure of meeting him), it was a dealer who first suggested the "hot rod" transformer upgrade. It consists of higher quality Vishay resistors, Jensen caps and Sledgehammer chokes. That is now a popular factory option (I have it).

    As for the market, I'm convinced that most of it will certainly return. The inherent value of most companies really didn't evaporate over night. I watched many digits disappear in my portfolio as well. Best of luck to you. As Feanor indicated, you may need to experiment a bit with the xover. The DQ-10s are well worth the effort.

    rw

  11. #11
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    I agree with your thought process entirely.

    I had encountered the same dilemma with my DQ-10s when one of my dome tweeters began misbehaving. In my case, the bad tweeter would make itself evident at certain frequencies--usually with piano. This misbehavior usually emerged as a buzz which I struggled to isolate. Eventually that occasional buzz degraded into all out distortion which I could identify as the dome tweeter just by placing my ear near each driver. I made sure it wasn't the sound boards or the mounting hardware and was confident that one of the dome tweeters had truly gone bad.

    Armed with this information, I proceeded to the Regnar website. In the online store, I was faced with replacement of the dome tweeter at a cost of $104.97 each. To further add to my pain, they highly recommended replacing both tweeters as matched pairs. That would be $210 for a pair of dome tweeters-nearly what I paid for the pair of speakers!

    Like you, I too was compelled to search for alternatives and found a comparable fabric dome tweeter with very similar specs as the original. The Vifa fabric dome tweeter was almost a perfect match both dimensionally and performancewise. (Even the rated impedence was identical between the Dahlquist and Vifa drivers at 6 ohm) The cost was $27.50 each from an online retailer. That's roughly 74% less than the rebuilt Regnar drivers. Taking Regnar's advice, I purchased a matched pair and fabricated my own mounting board to the same dimensions and replaced the originals using sheet masonite available at any home improvement store.

    I did not want to modify the existing masonite boards because the serial numbers were located on this specific board. I also wanted to keep the option available to have Regnar rebuild the OEM tweeter in case the Vifa alternatives did not satisfy me.

    The results were pleasantly uneventful. The Vifa tweeters blended in with the other 8 Dahlquist drivers beautifully. So much so that I had forgotten that I had performed this repair and recently stumbled across a box with the old tweeters in them--The idea of sending these original OEM tweeters to Regnar for rebuild had long since been removed from my memory.

  12. #12
    Forum Regular audio amateur's Avatar
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    Quote Originally Posted by emaidel
    Point taken. Those that I ordered are 8 ohms, but as I have no way to determine their efficiency (amongst other characteristics) as compared to the stock driver, I just have to wait until they arrive and I install them to see if they'll work well. Fortunately, I can return them to Parts Express in the event they don't. Then, I guess, I'll be stuck paying Regnar their very high cost (over $150) to rebuild a relatively ordinary, initially inexpensive driver. Moreover, I'll likely have to have both midbass drivers rebuilt, as since one crapped out, it's very likely the other one will too. If that's the case, then I will have wound up paying more to repair the DQ-10's (woofers and midbass drivers) than I paid for the speakers themselves, having purchased them at an industry-insider's customary discount of 50% off list, which at the time was $500 per speaker.
    Sorry to hear about that. But hey, you've an option! get rid of the E-class

  13. #13
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    Quote Originally Posted by audio amateur
    Sorry to hear about that. But hey, you've an option! get rid of the E-class
    As the Mercedes is the only vehicle we presently own (and we do own it outright), that's not any too likely. I just completed yet another drive from Moore, SC to Long Island, NY in it and despite its 4,700 pound weight, and V-8 engine, I averaged 27 mpg at a relatively constant 80 mph. To drive at that speed with the company of my wife and two Springer Spaniels, in considerable comfort, attain such high mileage, and arrive wide awake and not fatigued after 12 1/2 hours of driving speaks very highly of the car.

  14. #14
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    Quote Originally Posted by emaidel
    As the Mercedes is the only vehicle we presently own (and we do own it outright), that's not any too likely. I just completed yet another drive from Moore, SC to Long Island, NY in it and despite its 4,700 pound weight, and V-8 engine, I averaged 27 mpg at a relatively constant 80 mph. To drive at that speed with the company of my wife and two Springer Spaniels, in considerable comfort, attain such high mileage, and arrive wide awake and not fatigued after 12 1/2 hours of driving speaks very highly of the car.
    I'll say, that's pretty impressive mileage for a V8! Which generation E is it? Ever heard of the E55 AMG?

  15. #15
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    It's a 1997 E-420 that I've kept in pristine condition (I'm very definitely nuts in that regard!)since we bought as a used "Starmark" vehicle in 2001. Even when it was in the Mercedes shop for repairs (something it's required a good deal more often than I would have expected for such an expensive car) I always had a loaner, which was usually a brand new C-class something, including the Kompressor model. No matter how new, nor how powerful (as in the case of the Kompressor) any of the C-class models were, once I got back into my far older vehicle, I always preferred my car over the others. I doubt I would have felt the same way had they lent me a new E-350, or E-500 though. And, on a few occasions the loaner was an M-class, and I thought they were downright awful - at a $10,000 over the Nissan Pathfinder we had at the time, there was nothing at all to suggest that the Mercedes M-class was worth anywhere near that much money.

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