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1B's are peaking in the 1kHz range . . . will new capacitors help?


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I have been restoring vintage speakers. So far, recapped a pair of Dahlquist DQ-10's, AR 28's, and Quart S Reference . . . the Dahlquist's needed new woofers and the AR's new tweeters.

The Vandersteen's are the original model (no letter in the ser#) and sound clear, but the highs are overpowering, and turning the tweeter adjustment all the way down doesn't help.

Photo is of the crossover inside the woofer cabinet . . . any ideas, suggestions, recommendations?spacer.png

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After more research, it may be the high pass capacitor is not 'rolling off' properly. It should not let through frequencies below 2kHz in a two-way speaker?

Some specs and values would help. 

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We have not had a cap fail in 45 years as they are high quality film types.  A two way speaker is a bundle of compromises especially when you want it to be time and phase correct, easy to drive, have bass and be affordable.  I have more development time in the Model One than any other Model in  our line.  Many have installed improved wire, caps and even drivers and found the same compromises just a different flavor.  If you are seeking improved resolution in the mid/treble range you should get a pair of Model Two something's as they have a midrange.  The first order crossovers required to be time and phase correct will get harsh at higher listening levels (louder than I listen for sake of my ears) because the woofer and tweeter get over worked.  This is all in fun I know so have at it.

RV                                                                                                                                                                                                       

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Thank you Richard.

As I mentioned, restoring vintage speakers is a hobby as I hate to see beautiful things go into the trash . . . and studying up on your product, I decided to explore your speakers.

My biggest job was replacing the 16 capacitors in an old pair of DQ-10's . . . running bad capacitors puts the drivers at risk of failure. They now sound fantastic . . . smooth, and I regularly play them at 90 db @ 3 meters.  I don't want to play the Vandersteen's at that level, only being two-ways . . . but if the caps are shorting out the drivers will be compromised, ruined. 

Yes, I could write a check for a pair of three-way Vandersteen's, but that expense is not a priority. I have drunk Petrus Pomerol '55, but will never buy another bottle. And, I do have the Dahlquist's . . . 

CAPACITORS in the 1B, FILM? OR ELECTROLYTIC?

As you can see from the photo, the capacitors look like crimped 'cans,' so are Electrolytic, not film. Am I mistaken? If they are film, mylar, then I will leave them in. But, at this age electrolytics should be replaced. 

You say the 'First Order Crossover' (one capacitor per driver) will be shrill/more treble at higher volumes (I didn't go above 80 at 3 meters). My MB Quart S's are two-way with Titanium Reference Tweeters (your tech told me the 1B's were silk and they look like aluminum) and while, like your 1B's, aren't designed for 90-100 dB full concert volumes, do not suffer from too much treble at higher volumes.  They are amazing speakers, much smaller than the 1B's, floor standing two-ways with a 'balanced' port (semi-acoustic suspension). I think they are rated 4 ohms . . . the Vandersteen's use 8 ohm drivers. 

Edited by LAD
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Welcome to the forums LAD.  I'm glad you made it and as I said, Brad or Richard was bound to respond.  I hope that you check out all the other threads, especially the music ones as there are some great ideas for well recorded and great music.  

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3 hours ago, LAD said:

Thank you Richard.

As I mentioned, restoring vintage speakers is a hobby as I hate to see beautiful things go into the trash . . . and studying up on your product, I decided to explore your speakers.

My biggest job was replacing the 16 capacitors in an old pair of DQ-10's . . . running bad capacitors puts the drivers at risk of failure. They now sound fantastic . . . smooth, and I regularly play them at 90 db @ 3 meters.  I don't want to play the Vandersteen's at that level, only being two-ways . . . but if the caps are shorting out the drivers will be compromised, ruined. 

Yes, I could write a check for a pair of three-way Vandersteen's, but that expense is not a priority. I have drunk Petrus Pomerol '55, but will never buy another bottle. And, I do have the Dahlquist's . . . 

CAPACITORS in the 1B, FILM? OR ELECTROLYTIC?

As you can see from the photo, the capacitors look like crimped 'cans,' so are Electrolytic, not film. Am I mistaken? If they are film, mylar, then I will leave them in. But, at this age electrolytics should be replaced. 

You say the 'First Order Crossover' (one capacitor per driver) will be shrill/more treble at higher volumes (I didn't go above 80 at 3 meters). My MB Quart S's are two-way with Titanium Reference Tweeters (your tech told me the 1B's were silk and they look like aluminum) and while, like your 1B's, aren't designed for 90-100 dB full concert volumes, do not suffer from too much treble at higher volumes.  They are amazing speakers, much smaller than the 1B's, floor standing two-ways with a 'balanced' port (semi-acoustic suspension). I think they are rated 4 ohms . . . the Vandersteen's use 8 ohm drivers. 

The electrolytic caps are not part of the high or low pass networks by are impedance compensating networks.  Your MB Quart speakers use high order networks which is not time and phase correct but make life for the drivers much easier!  Not the same but maybe you are not sensitive to time as your DQ-10's are also not time or phase correct.  No big deal as many are not sensitive to time.

RV

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  • 2 weeks later...

The DQ-10's are time phased arrays, designed by the engineer who built the Apollo Lunar Module. They use minimal baffling plus some open tweeters with felt sound absorption material, not unlike the minimal enclosure on the 1B. They are still considered one of the top 10 speakers ever made, and treasured by audiophiles. 

The capacitors control roll-off in the crossover. Right? And these electroytics are 40+ years old . . . so I am replacing them. 

The Crossovers in the 1B's are not easy to work on . . . everything is tight and glued in there. So, I snipped out the two electrolytic caps (Vandersteen branded 10%-ers) and will install Dayton (5% tolerance) and Solen audiophile grade film caps (1%-ers). We'll see if that smooths out those highs . . . I glued down loose veneer and used a flame to burn off the pulls in the sock. The 1B's won't be 100%, but will look perfect at a few feet away. 

And, they will get set up right so I can hear what they can do creating the great soundstage they are noted for. 

So . . . hopefully these will play nice and be used for another few decades. 

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@LAD, not to be argumentative, but the DQ-10s are not time and phase aligned speakers. Here's some detailed insight into he crossover. 

https://community.classicspeakerpages.net/topic/9355-dq-10-crossover-rebuild-ready-to-solder-help/

The drivers may be staggered, but electrically, they are not, and cannot be, time and phase aligned. This topic can get really complicated, really quick, but here's an easy tell: the mid-woofer is wired "backward" with respect to the woofer, which means when the woofer pushes out, then mid-woofer wants to push in. However, without electrical compensation, that would create a big suck-out. The crossover rotates the phase of the mid-woofer frequencies 180-degrees to compensate. So, even if those 2 drivers are "aligned" to the peaks of a given frequency, those peaks will be 360-degrees out-of-phase.

This may be the most backwards description of crossover design ever articulated, but I think it makes the point.

Now, this doesn't mean the DQ-10 is a bad speaker - I've ready many positive things about this speaker. There's very little "good" or "bad" in solid engineering - only trade-offs. True time and phase alignment just wasn't this designer's priority, irrespective of what else he's built.

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I have heard the DQ's extensively over the years.  A good friend owned a pair when they first came out.  IRT being a top ten speaker of all time, that's just too subjective.  Sound wise, they are in no way a top sounding speaker.  As renter pointed out, it's not a bad speaker adn many folks love them.  

Every piece of audio gear is a trade off. That's why we usually align ourselves with designers that make the trade off's that we like.  It's also why the 'top rated' piece won't play nicely with some other top rated piece.  Synergy of trade off's is the most important thing I guess.

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  • 4 weeks later...
On 5/18/2021 at 8:33 AM, ctsooner said:

I have heard the DQ's extensively over the years.  A good friend owned a pair when they first came out.  IRT being a top ten speaker of all time, that's just too subjective.  Sound wise, they are in no way a top sounding speaker.  As renter pointed out, it's not a bad speaker adn many folks love them.  

Every piece of audio gear is a trade off. That's why we usually align ourselves with designers that make the trade off's that we like.  It's also why the 'top rated' piece won't play nicely with some other top rated piece.  Synergy of trade off's is the most important thing I guess.

My first speakers were a pair of DQ-M5s. A two way speaker with a nice punchy mid-bass.  Yum!

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On 5/17/2021 at 2:06 PM, nrenter said:

@LAD, not to be argumentative, but the DQ-10s are not time and phase aligned speakers. Here's some detailed insight into he crossover. 

https://community.classicspeakerpages.net/topic/9355-dq-10-crossover-rebuild-ready-to-solder-help/

The drivers may be staggered, but electrically, they are not, and cannot be, time and phase aligned. This topic can get really complicated, really quick, but here's an easy tell: the mid-woofer is wired "backward" with respect to the woofer, which means when the woofer pushes out, then mid-woofer wants to push in. However, without electrical compensation, that would create a big suck-out. The crossover rotates the phase of the mid-woofer frequencies 180-degrees to compensate. So, even if those 2 drivers are "aligned" to the peaks of a given frequency, those peaks will be 360-degrees out-of-phase.

This may be the most backwards description of crossover design ever articulated, but I think it makes the point.

Now, this doesn't mean the DQ-10 is a bad speaker - I've ready many positive things about this speaker. There's very little "good" or "bad" in solid engineering - only trade-offs. True time and phase alignment just wasn't this designer's priority, irrespective of what else he's built.

I just checked out that circuit diagram.  I certainly agree that the best you can hope for is a 360 rotation in phase.  It would be interesting to see this circuit modeled in software.

I re-capped some KLH speakers for my son.  At the time I googled re-caps of Vandersteens.  Not. one. single. result. Nice.

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  • 5 months later...

I pulled all the electrolytic caps and had them tested . . . they were bad. Inserting new audiophile grade caps is a challenge, the crossover buried so deep and impossible to remove. I cracked one board trying, but I think the continuity integrity is fine. Worse than working on an Audi.

 

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I don't think anyone works on a 40 year old Audi.  All off the caps in the signal path are bypassed by film caps which reduces wear and tear on the electrolytic caps.  I have never found a bad cap in 45 years and I would love you to send me one that measured bad.  We service the crossovers in place, FYI.  Takes some skill but for once in 40 years we have it.

RV

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34 minutes ago, LAD said:

I pulled all the electrolytic caps and had them tested . . . they were bad. Inserting new audiophile grade caps is a challenge, the crossover buried so deep and impossible to remove. I cracked one board trying, but I think the continuity integrity is fine. Worse than working on an Audi.

 

The electrolytic caps are mostly impedance compensating circuits not in the signal path. A coil is used to roll off the woofer and 2 film caps are the tweeter high-pass.

RV

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20 hours ago, LAD said:

I pulled all the electrolytic caps and had them tested . . . they were bad. Inserting new audiophile grade caps is a challenge, the crossover buried so deep and impossible to remove. I cracked one board trying, but I think the continuity integrity is fine. Worse than working on an Audi.

I am probably a bit of a Luddite, as I only see an opportunity to pull the XO out and try going active.

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