Hello @AudioCarMan , were you able to see a part number anywhere on that midrange? Both of mine are zeroed out on the ohm meter and may remove them and dive in myself. Some finicky patient stuff there but we will see
Dahlquist DQ-10 bigdome midrange - Crossover problem?
- Thread starter AudioCarMan
- Start date
Audiocarman,
You may have a rubbing voice coil. Try slightly loosening the bolts on the face place and moving the voice coil in its gap to see if the "noise" goes away. There are threads that describe doing this with ADS tweeters and dome mids. If you have a signal generator, play a sine tone at a frequency that would be in the range of the driver and adjust until the sound is clean and at a maximum of volume. I've done this and it works great.
The Vaseline is probably just a bit of lube to crutch a rubbing voice coil. If it is rubbing it will eventually be damaged and fail.
Good luck,
John
You may have a rubbing voice coil. Try slightly loosening the bolts on the face place and moving the voice coil in its gap to see if the "noise" goes away. There are threads that describe doing this with ADS tweeters and dome mids. If you have a signal generator, play a sine tone at a frequency that would be in the range of the driver and adjust until the sound is clean and at a maximum of volume. I've done this and it works great.
The Vaseline is probably just a bit of lube to crutch a rubbing voice coil. If it is rubbing it will eventually be damaged and fail.
Good luck,
John
AudioCarMan
Member
Hello @jhouse55. I didn't see any part numbers, unfortunately. On this same thread @tubed mentioned that "The Dahlquist mid domes are the Peerless 4 ohm version of the Peerless 8 ohm mid domes used on the Infinity Quantum series." They don't make them anymore. Before you spend money on replacements/originals from somebody that has decided to part out with them, I invite you to try to fix them yourself.
You probably will have to do the same I did. You just need to cut the tinsel wire and replace it with a "thin hair" of speaker wire, just like in the picture below. Don't you unscrew and open the midrange unless replacing the tinsel wire doesn't work. Don't dive in it unless this first option doesn't work.
Note in the pic below that I didn't touch the portion of the tinsel wire that is touching/in contact with the soft dome, just the other portion of the tinsel wire.
I hope this helps!
AudioCarMan
Member
Thank you for your advice. The problem is that when I loosed the bolts slightly and found a clean sound after moving the plate a little bit, then I had to screw/tight the loose bolts and this made the midrange sound bad again. This is why I advice not to open the midrange but instead try fixing it replacing the tinsel wire from outside without opening it.
In my experience, any slight movement or vibration would make the midrange sound slighty bad or detuned at certain frequencies even if I just had to screw a bolt a little bit. Luckily the Vaseline helped and I think I fixed it. In any case, I got the pair of speakers for a very good price so I just went ahead and bought a "new" midrange on Fleabay to make sure I wasn't going to have to messl with it more. As you guys can imagine, my wife didn't like that after occupying the livingroom with "your huge speakers", one of them wouldn't sound good, so I had to get the "new" midrange quick. I kept the one I had just fixed just in case I need to use it in the future. Here I have several videos that show how the midrange sounded much better/perfect? after using lube (the before and after).
Last edited:
Deer Creek
New Member
Blue Shadow
Waiting for Vintage Gear from this century
Pretty soon we will have replaced all the drivers except that advent woofer.
HoltHill
Guest
There's a lot of VERY ODD information flowing from this thread. Vaseline? Doesn't mean the voice coil isn't rubbing, it just means you added enough sludge to the voice coil gap to make the rubbing sound low enough that your ears can't detect it. Whomever recommended this should never be allowed around speakers ever again.
Sounds like you repaired the midrange, but did not align the VC properly. Open it up, clean the sludge, and give it another try. Try to play a 1,000Hz cycle through the midrange at low volume so you can hear the point where the VC is aligned properly. It should be obvious. If the VC starts to run after tightening the bolts, try rotating the faceplate, or shimming he faceplate with thin pieces of cardboard. In my experience, these Philips mids were sometimes manufactured with the VC slightly off-true, and the issue was corrected when mounted to the magnet assembly. But when the drivers are disassembled, things fall out of line again. It's a patient process.
0.75 or 0.80 mA fuse doesn't make any difference really. It's just a protection circuit, so anything in that range will do.
If you need more help, let me know. I work on DQ-10s all the time. Just finished this set yesterday.
Sounds like you repaired the midrange, but did not align the VC properly. Open it up, clean the sludge, and give it another try. Try to play a 1,000Hz cycle through the midrange at low volume so you can hear the point where the VC is aligned properly. It should be obvious. If the VC starts to run after tightening the bolts, try rotating the faceplate, or shimming he faceplate with thin pieces of cardboard. In my experience, these Philips mids were sometimes manufactured with the VC slightly off-true, and the issue was corrected when mounted to the magnet assembly. But when the drivers are disassembled, things fall out of line again. It's a patient process.
0.75 or 0.80 mA fuse doesn't make any difference really. It's just a protection circuit, so anything in that range will do.
If you need more help, let me know. I work on DQ-10s all the time. Just finished this set yesterday.
Blue Shadow
Waiting for Vintage Gear from this century
spell check on the rub.
Dang big caps for the piezo!!
Should sound really nice. Have you heard a pair with film cap for the midwoofer that 80µF unit?
If it is spec'd for a 0.8A, it gets a 0.8A. Not much difference from the readily available .75A but one is mentioned to be used and the other is not. but mentioned by the folks that do Dahlquist now. So as you say who cares. Maybe my ocd.
First I have seen your new name. I like the upgrade.
Last edited:
Interestingly, “run” is spelled correctly!
I use electrolytics on the mid-woofer cut off.
Blue Shadow
Waiting for Vintage Gear from this century
If the voice coil starts to run after tightening the bolts, try rotating the faceplate. Yes, run is spelled correctly but I read it as you might have meant rub. My bad, I guess.
Bill Ferris
Lunatic Member
, 
AudioCarMan
Member
There's a lot of VERY ODD information flowing from this thread. Vaseline? Doesn't mean the voice coil isn't rubbing, it just means you added enough sludge to the voice coil gap to make the rubbing sound low enough that your ears can't detect it. Whomever recommended this should never be allowed around speakers ever again.
Sounds like you repaired the midrange, but did not align the VC properly. Open it up, clean the sludge, and give it another try. Try to play a 1,000Hz cycle through the midrange at low volume so you can hear the point where the VC is aligned properly. It should be obvious. If the VC starts to run after tightening the bolts, try rotating the faceplate, or shimming he faceplate with thin pieces of cardboard. In my experience, these Philips mids were sometimes manufactured with the VC slightly off-true, and the issue was corrected when mounted to the magnet assembly. But when the drivers are disassembled, things fall out of line again. It's a patient process.
0.75 or 0.80 mA fuse doesn't make any difference really. It's just a protection circuit, so anything in that range will do.
If you need more help, let me know. I work on DQ-10s all the time. Just finished this set yesterday.
Nice pictures! The person that told me about using a little bit of vaseline in the midrange was an experienced repairman on eBay that worked repairing big dome midranges such as the ones that ADS installed, and other speaker parts. He has had a good amount of happy costumers. He is still on the Bay offering his services I think. It also makes a lot of sense what you say in your message.
I tried many times to allign everything correctly, and even at the end of the process, tightning the screws would change the tonality. One can try to allign everything perfectly, but when one tights the screws, in the last three seconds, the sound can change and produce this metallic sound:
The only thing that worked for me was rubbing a very small amount of vaseline, as I said. If I ever have this problem again I will just reconnect the tinsel wire instead of openning the whole thing.
When I was trying to insert the screws, any subtle vibration would move the allignment, like this video shows:
After rubbing a small amount of vaseline on the external groove of the voice coil:
By the way, I am a student, so I don't have much space in my apartment for the Dahlquists (or almost any speakers), so they spent most of their days stored. Two days ago I installed them just to remember their sound and recreate myself (with the sound) and... Oh my God!
Even my wife was impressed with it. At some point in the future the Dahlquists will be installed and never moved. But for now, I can just take them out of the storage, install them and listen to them every once in a blue moon.
Thank you, Audiokarma, for helping me fix them, and most especially, the very patient and knowledgeable @Blue Shadow.
By the way, how far away from the floor should they be? I was never able to find stands for these. It is hard to find them. (Edit: I just found some info here).
I have even considered buying stands and installing little wheels in the stands so I can move them around the apartment when needed. Does this sound like a bad idea?
Last edited:
My rebuilt factory stands hold them 11" off the floor.
If wheels means you can hear them more often, then that sounds good to me, just be careful because they are kind of awkward buggers, and you don't want them taking a tumble. A pretty wide and deep base might be necessary for stability.
Blue Shadow
Waiting for Vintage Gear from this century
Stock feet were about 3" raising the speaker very little with a bit of tilt back. Two versions of the stands were available at different times. I think the early stand was the three riser stand and the second one was the single monolith-type riser. Both raised the speaker about 12", George mentioned 11" above and since I don't have stock stands my guess is from the Dahlquist.io group files. The stands I have were made taller to accommodate my listening situation.
Just fine adding wheels to the stands if
You are careful so the speaker isn't pushed off the stand when moving
You have a large enough bottom base to support the speaker when the wheels are added
You understand that wheels aren't best as you really want the speakers planted in place
But it will allow you to listen to them more. I would make stand for the final install and then add wheels and live with the speaker a bit higher than final because that will be temporary.
Try a few different heights to find what you like.
Just fine adding wheels to the stands if
You are careful so the speaker isn't pushed off the stand when moving
You have a large enough bottom base to support the speaker when the wheels are added
You understand that wheels aren't best as you really want the speakers planted in place
But it will allow you to listen to them more. I would make stand for the final install and then add wheels and live with the speaker a bit higher than final because that will be temporary.
Try a few different heights to find what you like.
Last edited: