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Dahlquist DQ-12 woofer replacement

J

jbush

New Member
I just got a pair of Dahlquist DQ-12s and one of the woofers is shot - foam surround and spider.:tears: I know that Regnar will rebuild the woofer, but I don't know what the cost is. I am also concerned about having the woofer rebuilt as I don't know if the voice coil or motor structure might have been damaged. I have heard that Dahlquist used Advent woofers. Is this true? Does anyone have the T/S specs for the Dahlquist drivers?

What about replacing the woofer with a new 8" driver? I know the crossover is at 400Hz, so could I just replace the woofer with another 8-incher... wait, without the T/S specs it probably wouldn't sound the same. Hmmm, what to do? Any ideas?
 
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Post a picture of the woofer out of the cabinet. Front and back. Might be able to ID the OEM... and possibly recommend a proper retro-fit or repair option.

Regards,
Gordon.
 
Thanks for the response Gordon. Here is the front:
IM000857.jpg

And here are the markings on the back (X4515 1056 9001):
IM000858.jpg

And here is the damaged spider:
IM000860.jpg

You can see that the spider didn't just seperate, it is actually torn.
Oh, by the way, I also received the original owner's manual for the "DQ-12 Phased Array" - I can scan and email it if anyone is interested.
 
That's a Gefco-built driver. Similar to some used in some later Advents, but not exactly the same.

I've been able to fix that problem, with the spider... as long as the voice coil itself isn't damaged, the dustcap can be removed, the spider and surround removed and the lead wires unsoldered, and the cone removed. Once it's removed, it's possible to carefully trim away the spider from both the basket and cone, and install a new spider, using shims to center the coil in the magnet gap. A new surround and the dustcap glued back in, and it's good to go...

Regards,
Gordon.
 
What do you think about finding another 8" driver that models well in the sealed enclosure and using it? I like the idea of newer rubber surrounds, but I am concerned that it might take away too much of the original speakers' character (and the whole time-delay-corrected driver crossover benefits).
 
If Alon is still around, they might use a similar or the same woofer, since their designs are similar (same designer).
 
jbush said:
...
Oh, by the way, I also received the original owner's manual for the "DQ-12 Phased Array" - I can scan and email it if anyone is interested.
Click to expand...

Call me interested!!!!

Today I found a pair of Dahlquist DQ-12s, and could not be happier!

:tresbon:

.
 
When you must replace a driver with a non original, the woofer is the one that will least affect the overall "sound" of a speaker. Yes, it must be chosen to work well in the existing cabinet and have similar sensitivity.

The midrange and tweeter affect the overall sound much more. It is much more difficult to replace them. When I do this, I usually replace both sides.

Give me some info on your cabinet size, and if ported, diameter and length of the port. Also, sensitivity of the speaker.
 
I just had my dahlquist woofers rebuilt by Regnar.
The cost is $130.00 per woofer plus shipping. And they prefer if you send both woofers, so they'll match. My total cost was around $290. including shipping.
 
jbush thanks for posting those pics!

My yesterday score DQ-12s have the exact same 8-inch driver, so they are the quality originals!

GordonW thanks for naming them, Gefco.

Saint Johnny all the net reviews on Regnar seem in perfect agreement about their service/work quality. Such unanimity is unheard of, so they'll hear from me when I need it.

My initial review is on this thread, don't wanna duplicate and waste bandwidth...

I looked all over the net for info on them.

Lots on DQ-10, much less on 20s and nearly zilch on the 12s.

jbush, is it possible to scan that Manual? Or if it's easier I'll gladly take care of postage/cost for xeroxes. Cheers!

These are absolute keepers.

.

now playing: some seriously melancholy blues... "just gotta be by myself..."
 
Susurus said:
Saint Johnny all the net reviews on Regnar seem in perfect agreement about their service/work quality. Such unanimity is unheard of, so they'll hear from me when I need it.
Click to expand...
I just hope you aren't in a rush to get them back! Mine took NINE weeks!!


Susurus said:
I looked all over the net for info on them.

Lots on DQ-10, much less on 20s and nearly zilch on the 12s.
Click to expand...

And even LESS on the DQ-6's!!!
 
Well my foam gave out. Could have been the jolt from a bi-amp experiment gone ah... haywire...

or just old original foam beyond its life expectancy.

And yes, the spider is separated too! jbush, you really have banked up oodles of Karma with your posts and pics here... hope you stumble across curbside 'Free-take me' Tannoys... :thmbsp:

Thank you :angel:

.
 
jbush said:
I just got a pair of Dahlquist DQ-12s [...] I have heard that Dahlquist used Advent woofers. Is this true? Does anyone have the T/S specs for the Dahlquist drivers?
...
Click to expand...

What I've read is that a small first run of the DQ-10's did, after that either they modified or redesigned them. The resemblence is no accident.

Got in some Advent 3002's. Since they're recent refoam jobs, their woofers will live in my DQ-12's until I perfectly re-foam and re-spider.

Clearly the 12's don't sound the same with the Advent woofers.

The round ceramic and metal magnet pieces from the DQ-12's woofers are much heavier than the square ones from the same diameter Advents. Mine (SN 001255-6) have the same markings on the back as yours (X4515 1056 9001).

--

However the DQ-20i's woofers do have the Advent look... square magnets. Thin, uncast.

The ribbing and inverted foam strongly suggests that they are the same as the DQ-10's woofs.

The seller claimed they were all original... but I don't know fer sure... :para:

Don't know if a modern cast/better woof would throw off the original synergy so much that you'd need to re-engineer the crossovers.
And the cabs. And ... shoot. The spacing, tilt angle, stagger placement...

arghhhh.... :bash:



---

DQ-10 : 1974?- ?
DQ-20 : 1988-
DQ-20i : 1989-1992 about.
DQ-12 : 1990- about. last of the 3 way sealed Acoustic Suspension Dahlquists?

---

Sure a Canadian company bought the name. Haven't heard any of those 'new' models yet...one sports an isobaric dual woofer...that's exotic!
 
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