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Hi everyone, hope you and families are well.
Been looking for information on what I have, and suggestions on what should be done. Not a tech or am knowledgeable about specifics like brands of parts etc., but have a basic general understanding.
Well, bought my 10s, S/Ns 01927 – 01932, around winter 1975- early 76 (or 76-77?) from the original owner who got Magnaplanars. Had the small legs (got the stands when they came out), and had the mirror image done in 1977. Had the woofers (they are the Advents) rebuilt by Dahlquist in 1988.
In 1990 I installed the Mylar caps as seen in the pictures. Don’t remember what the originals were. Have no idea of what brand these are but I did one speaker and then A/Bd them and there was a distinct improvement.
Mainly looking for advice/info on the crossovers. Just looking for maybe a ‘tune-up’, not getting too deep into this.
Have not heard these since fall 1994 (long story) and want to set them up for my son at his house. He has had them there for some years but I am now just getting to the point where I need to get this done. Now he digs his music but is not into the Audio system world. He would like to have whatever I can set up for him to use occasionally and delve into my vinyl collection. I know he will love it once he hears them. Due to living arrangement and health/medical issues I hope to be able to share some time with my son and hear my 10s again.
So, in all these years, I have yet to see a picture of a DQ-10 crossover like mine with the tweeter fuse mounted on the crossover board and not the baffle. This is something I would really like to know about.
Came across a post here by John van Son #5853 Sept. 11 (DQ-10 Regnar Cap Upgrade) where I finally found a reference to one of the things I have wondered about. I have 2 40uF caps instead of a single 80uF. Am confused about seeing pictures of large 80uF caps and then small ones. Can someone clarify that? Suggestions?
Thanks for reading this and hope I didn’t ramble on too much. New at posting, hope this comes across?ok.
 
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Dear raudio44,
When capacitors are connected in parallel,?the total capacitance is the sum of the individual capacitors' capacitances. If two or more capacitors are connected in parallel, the overall effect is that of a single equivalent capacitor having the sum total of the plate areas of the individual capacitors.
In your case, 40 + 40 = 80.?
Copied from:
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Thanks for the reply. I did understand about them being parallel. My questions were related to the version / appx date of the crossover (speakers) and about the sizes of 80uF caps I have seen. I have seen very large ones and then much smaller ones. So, are these size differences related to different types? that is what has my unsure of what I have seen. Have read some posts where they are strapped to the support let of the baffle because of their large size. I do know that crossover caps should be non- polarized but have seen them both large and small.
Then are there any changes from this version that should be considered?
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This should have been in my original post. I have done some homework going off the schematics I have found.
Early version: 2 40uF caps parallel off POSITIVE side of Woofer with only ONE 4ohm resistor between Woofer and CAPs.
Schematic labeled serial #4134 and above has 80uF CAP off NEGATIVE side of Woofer with TWO 4ohm resistors in series off POSITIVE of Woofer.
?
Early shows C2 C3 off POSITIVE of Midrange and in later schematic showing position in drawing of Midrange reversed C2 and C3 are off the NEGATIVE side. Also shows fuse where in early version there is none. That comes back to my other query where mine have a fuse mounted to the crossover board.?
I may be missing things or mis-understanding of circuits/schematics.
query   ?
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I have never seen the top schematic. It is not the functional equivalent of the bottom one which is correct.
There are variants with small value variations out there. The fuse is only for protection and it does not matter where it is mounted as long as it is in series with the tweeter. You can also jumper around it.
I have found the “original” drivers in my system have changed parameters significantly as they aged.
Most notably the tweeters had rock hard adhesive which had been sloppily applied that had leaked onto the underside of the surround and inhibited dome motion. I mostly fixed this using a process that I DO NOT RECOMMEND unless you are highly confident in your abilities. First I removed the dome and voice coil. Then I used a 1/8” wide Exacto knfe to gradually peel the adhesive away from the surround only. Once peeled away I careful cut it. This lowered resonant frequency of the dome and the sound improved greatly. The mid-domes are also stiff which I was able to help by carefully manually manipulating the surround using a qtip soaked in IPA.
these driver changes made bigger improvements to the SQ than replacing crossover caps. Mine caps are now similar to what you have in yours now but they have all been measured to assure they are operating correctly.
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Appreciate your information, thank you. I will check out what you have indicated when I can get the chance to see them. they have been at my son's and want to get them set up for him. Just been doing research to understand what I need to do. I am really unsure of what to make of my crossovers and the differences in the circuits between what is shown in the two schematics. As for the fuse mounting, I know it doesn't matter but was something I haven't seen elsewhere and curios as to why it was mounted there. has to be from the factory but when?
Concerning the drivers, I would not attempt to do what you did since I have not experience with that. FWI, in 1989 I installed new mid woofers and tweeters which I got from Dahlquist (when they were still the original company). Don't really know why I changed the drivers but they are newer than original FWIW. Also had the woofers rebuilt by them 1/1989.?
Going to do a refoam on the woofers which while never having done it before, seems like that should not be a problem.?
still would like to know what 80uF CAP to put in to replace the current 2 40uFs.?
?
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Dear raudio44,
in the crossover scheme the most relevant thing I notice is that the midrange is connected with reversed polarity. This would open a long discussion about the phase response of the DQ-10s, I just say that after long analysis and listening sessions I have reversed the polarity of both the mid-woofer and the midrange. I am very satisfied with this modification, which I have been able to compare with another pair of DQ10s that I own and which I have not modified. Various hypotheses can be made about the reverse connection of these speakers: if it was intentional it could have been a choice to increase the depth of the acoustic scene at the expense of the phase response, or, as some have hypothesized, it could have been mistakenly introduced in the process. of production.
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Bob Betts who was Bozaks electrical guru has a very good explanation about reversing mid driver polarity I’ll copy and attach. My listening experience found that non reversed produced a brighter sound and reversed less bright
Dear raudio44,
in the crossover scheme the most relevant thing I notice is that the midrange is connected with reversed polarity. This would open a long discussion about the phase response of the DQ-10s, I just say that after long analysis and listening sessions I have reversed the polarity of both the mid-woofer and the midrange. I am very satisfied with this modification, which I have been able to compare with another pair of DQ10s that I own and which I have not modified. Various hypotheses can be made about the reverse connection of these speakers: if it was intentional it could have been a choice to increase the depth of the acoustic scene at the expense of the phase response, or, as some have hypothesized, it could have been mistakenly introduced in the process. of production.
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"still would like to know what 80uF CAP to put in to replace the current 2 40uFs. "
The caps I would recommend are something like these. ?
IF the drivers were new and of higher quality i would choose these.?
Given the age of the drivers I doubt you will hear any difference.
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Dear?guida_f@..
The crossover scheme comments are Interesting. I have never tried that. I have reversed the polarity of the super tweeter and while it measures much better I can not hear any difference. I have also reversed the polarity of the tweeter (only) ?and that causes a 8 dB suck out in the range between the middle dome and tweeter. My speakers are wired as indicated on the right schematic above except the supertweets are reversed. So I can confirm that it is quite likely the right schematic at least as the designer intended.?
The network as applied has the drivers in phase quadrature so they are supposed to be constantly 90 degree out of phase with each other. The acoustic sum will be in phase with this wiring. However, if you invert the mid phase it will be 270 degrees out of phase which is to say 90 degrees in the opposite direction out of phase. Confusing? here is very old simple doc that explains this.
.
Figure 2 and 3 are the focus.?
Our crossovers, are used with aging drivers, who's parameters are not at all precise so it is entirely possible we are all listening to different speakers. The speakers may indeed sound better with the phase reversed.
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Slightly off topic but to answer the last question about why things are not as indicated I can attest to the fact that you are not the original factory owner it is quite likely people have mucked with them and usually for the worst. On the my 3rd owner DQ10-s I found the following significant things wrong:
- Multiple cabinet leaks due to improper sealing when the woofers were replaced.
- Both tweets wired out of phase.
- One tweeter had a fractured voice coil wire with intermittent contact.?
- Both dome mid ranges had stiff hardened suspensions.
- Both tweeters had hardened adhesive under the surrounds that prevented proper dome motion.
- Intermittent high resistance contacts on all 4 system fuses.
- Tweeter level pots were scratchy. Totally mis-set level above 5 KHz was 3 dB too high on one speaker, 2 dB to low on the other.
- One super tweeter wire was not soldered at all.
- Multiple questionable ( cold) solder joints, two fell apart when pulled on.
- Midrange crossover caps very old bulging electrolytic caps high leakage.
- Woofers not original factory spec but balance is adequate, extension only to 75 Hz or so with no EQ.?
- Woofers both wired out of phase with rest of system.
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there are a couple of 80UF choices for the woofer cap. Solen may be the best choice. Im attaching again the rebuild docs with tow diff parts lists
On Wed, Nov 24, 2021 at 3:36 PM Charlie Conger < ctconger@...> wrote: Slightly off topic but to answer the last question about why things are not as indicated I can attest to the fact that you are not the original factory owner it is quite likely people have mucked with them and usually for the worst.
On the my 3rd owner DQ10-s I found the following significant things wrong:
- Multiple cabinet leaks due to improper sealing when the woofers were replaced.
- Both tweets wired out of phase.
- One tweeter had a fractured voice coil wire with intermittent contact.?
- Both dome mid ranges had stiff hardened suspensions.
- Both tweeters had hardened adhesive under the surrounds that prevented proper dome motion.
- Intermittent high resistance contacts on all 4 system fuses.
- Tweeter level pots were scratchy. Totally mis-set level above 5 KHz was 3 dB too high on one speaker, 2 dB to low on the other.
- One super tweeter wire was not soldered at all.
- Multiple questionable ( cold) solder joints, two fell apart when pulled on.
- Midrange crossover caps very old bulging electrolytic caps high leakage.
- Woofers not original factory spec but balance is adequate, extension only to 75 Hz or so with no EQ.?
- Woofers both wired out of phase with rest of system.
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there are a couple of 80UF choices for the woofer cap. Solen may be the best choice. Im attaching again the rebuild docs with tow diff parts lists
On Wed, Nov 24, 2021 at 3:36 PM Charlie Conger < ctconger@...> wrote: Slightly off topic but to answer the last question about why things are not as indicated I can attest to the fact that you are not the original factory owner it is quite likely people have mucked with them and usually for the worst.
On the my 3rd owner DQ10-s I found the following significant things wrong:
- Multiple cabinet leaks due to improper sealing when the woofers were replaced.
- Both tweets wired out of phase.
- One tweeter had a fractured voice coil wire with intermittent contact.?
- Both dome mid ranges had stiff hardened suspensions.
- Both tweeters had hardened adhesive under the surrounds that prevented proper dome motion.
- Intermittent high resistance contacts on all 4 system fuses.
- Tweeter level pots were scratchy. Totally mis-set level above 5 KHz was 3 dB too high on one speaker, 2 dB to low on the other.
- One super tweeter wire was not soldered at all.
- Multiple questionable ( cold) solder joints, two fell apart when pulled on.
- Midrange crossover caps very old bulging electrolytic caps high leakage.
- Woofers not original factory spec but balance is adequate, extension only to 75 Hz or so with no EQ.?
- Woofers both wired out of phase with rest of system.
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The entire article explanation of effect of polarity
On Wed, Nov 24, 2021 at 3:55 PM richard adelberg via <richardadelberg= [email protected]> wrote: there are a couple of 80UF choices for the woofer cap. Solen may be the best choice. Im attaching again the rebuild docs with tow diff parts lists
On Wed, Nov 24, 2021 at 3:36 PM Charlie Conger < ctconger@...> wrote: Slightly off topic but to answer the last question about why things are not as indicated I can attest to the fact that you are not the original factory owner it is quite likely people have mucked with them and usually for the worst.
On the my 3rd owner DQ10-s I found the following significant things wrong:
- Multiple cabinet leaks due to improper sealing when the woofers were replaced.
- Both tweets wired out of phase.
- One tweeter had a fractured voice coil wire with intermittent contact.?
- Both dome mid ranges had stiff hardened suspensions.
- Both tweeters had hardened adhesive under the surrounds that prevented proper dome motion.
- Intermittent high resistance contacts on all 4 system fuses.
- Tweeter level pots were scratchy. Totally mis-set level above 5 KHz was 3 dB too high on one speaker, 2 dB to low on the other.
- One super tweeter wire was not soldered at all.
- Multiple questionable ( cold) solder joints, two fell apart when pulled on.
- Midrange crossover caps very old bulging electrolytic caps high leakage.
- Woofers not original factory spec but balance is adequate, extension only to 75 Hz or so with no EQ.?
- Woofers both wired out of phase with rest of system.
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On Wed, 24 Nov 2021 15:58:59 -0500, richard adelberg wrote:
The entire article explanation of effect of polarity
Bad URL. It triggers this message: "404 - Not Found". However, <> works.
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Hum. I’ll post the article then:
On Wed, Nov 24, 2021 at 7:52 PM John Joseph McVeigh < kd4vs@...> wrote: On Wed, 24 Nov 2021 15:58:59 -0500, richard adelberg wrote:
>
>
> The entire article explanation of effect of polarity
Bad URL.? It triggers this message: "404 - Not Found".
However, <> works.
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Your DQ-10s are from a time when two 40uFs were used in parallel for all of them. Your revision:?/g/DahlquistSpeakers/wiki/23611
?
Near as I've been able to tell, it was due to a supply issue or something similar. Those did plague Dahlquist in the early days (and drove the change from the CTS woofer to the Advent style), but they also did a lot of tweaking of the crossovers during this time. The crossover was giving Dahlquist some issues, which is why he brought Walter May in to try to improve it and, later, Marchisotto to finally wrangle the thing. So, it may even be they went with the smaller values during a stock order to allow some flexibility and ended up sticking with 80uF anyways.
With regards to that crossover schematic, I adjusted an extant schematic to match the configuration of a hand drawn schematic by another owner of a pair like yours. Putting it in there was a toss up decision for me, but I opted that it was better to have it there than not in case someone else encountered one that was weird like that and couldn't make sense of why it'd differ from the 4134 and above XO that everyone knows about. It is very possible that something was miswired in the decades since that pair was built making for the confusion. These aren't easy boards to keep track of what goes where just looking at them anyways, so its easy to get one's wires crossed and not just in the figurative sense. Then again, it may have been factory as changes with the resistors show. Speaking of which, for the resistors, those two in the top right were subject to an end user level modification to improve the damping factor on the woofer. There were two resistors there in earlier units, the mod removed one, factory units of the time of yours then came out that way and then more tweaks occurred and the second showed up again. The factory docs from that time don't include a full schematic, so anything from those days has to be sussed out from looking at units that, again, may or may not have been "tweaked" by the users. (Hence miswiring the midrange, which shows up as a tweak for various models of speakers over the years. The resultant null between the midrange and tweeter gives folks a false sense of smoother midrange [faking the "BBC dip"] and more detail because of the discontinuity. It's a bad idea to do in a good design that isn't an older one 'tuned by ear'.)
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Hello , I have DQ 10 since 1988. They work fine , but i would like to test especially?the tweeter.? I have no electronics to do so.? any idee's ?? ( my english is not perfect, sorry)
Op do 25 nov. 2021 om 22:10 schreef John van Son < jpvanson@...>: Your DQ-10s are from a time when two 40uFs were used in parallel for all of them. Your revision:?/g/DahlquistSpeakers/wiki/23611
?
Near as I've been able to tell, it was due to a supply issue or something similar. Those did plague Dahlquist in the early days (and drove the change from the CTS woofer to the Advent style), but they also did a lot of tweaking of the crossovers during this time. The crossover was giving Dahlquist some issues, which is why he brought Walter May in to try to improve it and, later, Marchisotto to finally wrangle the thing. So, it may even be they went with the smaller values during a stock order to allow some flexibility and ended up sticking with 80uF anyways.
With regards to that crossover schematic, I adjusted an extant schematic to match the configuration of a hand drawn schematic by another owner of a pair like yours. Putting it in there was a toss up decision for me, but I opted that it was better to have it there than not in case someone else encountered one that was weird like that and couldn't make sense of why it'd differ from the 4134 and above XO that everyone knows about. It is very possible that something was miswired in the decades since that pair was built making for the confusion. These aren't easy boards to keep track of what goes where just looking at them anyways, so its easy to get one's wires crossed and not just in the figurative sense. Then again, it may have been factory as changes with the resistors show. Speaking of which, for the resistors, those two in the top right were subject to an end user level modification to improve the damping factor on the woofer. There were two resistors there in earlier units, the mod removed one, factory units of the time of yours then came out that way and then more tweaks occurred and the second showed up again. The factory docs from that time don't include a full schematic, so anything from those days has to be sussed out from looking at units that, again, may or may not have been "tweaked" by the users. (Hence miswiring the midrange, which shows up as a tweak for various models of speakers over the years. The resultant null between the midrange and tweeter gives folks a false sense of smoother midrange [faking the "BBC dip"] and more detail because of the discontinuity. It's a bad idea to do in a good design that isn't an older one 'tuned by ear'.)
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Without test equipment simply place your ear near the tweeter,. You should hear a distinct change in level as you rotate the level control on the back. You should use a continuous sound for this, something like pink noise works the best. Once operation is verified have an assistant rotate the control while you listen from the normal listening position. The correct level is where the sound is the smoothest. This may be hard to hear at first but with a few minutes practice you will hear the best spot. Then adjust the second speaker so it sounds as close as possible to the same.?
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Bink audio cd. Download it as it has straight freq tones for about 39 sec of each freq . Easy to test drivers or xo’s
On Fri, Nov 26, 2021 at 12:40 PM Charlie Conger < ctconger@...> wrote: Without test equipment simply place your ear near the tweeter,. You should hear a distinct change in level as you rotate the level control on the back. You should use a continuous sound for this, something like pink noise works the best. Once operation is verified have an assistant rotate the control while you listen from the normal listening position. The correct level is where the sound is the smoothest. This may be hard to hear at first but with a few minutesnk practice you will hear the best spot. Then adjust the second speaker so it sounds as close as possible to the same.?
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Charlie Conger