Dahlquist DQ-10 Restoration

I picked up a pair of these for $150 on craigslist, but they are pretty old and dirty.

I am planning on restoring them to be in nice condition. The low end woofers look to be in good condition, but one of the midwoofer has a tear in the surround.

The crossovers are very old and dirty, the banana sockets are broken, and the crossovers are old and dirty.


5 Way hybrid open baffle system


Dirty old crossover




I was thinking of starting with the crossover. Should I scrap the whole thing, or just replace the capacitors?
Looks like these caps will be expensive with the amount I need...
And what about the wiring, should that be redone?

 

I'd do it in stages. Start with the caps. I'm not sure you'd need to mess with the Inductors/resistors/wiring unless something looks or tests bad.

A buddy of mine from work has a pair that he bought in the early 80's and he loves them, but he doesnt replace any of his gear unless it breaks beyond repair. I've never heard them. There was a local pair that went up for sale on Craigslist recently, but the guy wanted $500 for them. I thought that was too much but for the people that really like them, I'm told that isn't too unreasonable if they don't need work.

 

Yeah, that seems to be what they sell for in great condition. Mine were only $150.

I'll start with the caps. Those alone are around $100 total for the pair.

And cleaning everything...

 

Keep the inductors for sure. Those are just coils of wire and will last forever unless you do something stupid. Capacitors are the most likely candidate for replacement.

Surrounds can be replaced too, but I’m scared of messing with it. Did you try listening first or is it not functional?

 

The right way to do it if you are really hardcore is to measure all the drivers and get new T/S parameters and then develop a new crossover based on that. However that requires a lot of experience and would be super hard with a 5 way as your first rebuild.

 

I listened at the guy's house with unfamiliar material and source but it sounded fine. No banana plugs so I can really listen without taping on the wires like he did

 

I'd suggest the first thing you do for the crossover is take it apart, clean everything, and test each component. It'll look a lot less daunting once it's clean.

 

Ok, I'll do that. Sounds like a little bit of work, but not bad. I got my desoldering pump and multimeter.

 

I do want a t/s parameter measurer... I may ask for one for Christmas. But not design a new crossover now...

 

I wouldn't be too scared of doing a re-foam on the surrounds. I did all 4 woofer surrounds on my old pair of ADS 710's and it wasn't bad, just watched some videos on how to make sure the voice coils are properly aligned. Simply speakers has foam kits for the DQ-10 drivers. Here is a video of them doing one of the 10"


AudioKarma.org is a great resource for refurbishing vintage stuff. Most of the folks there are helpful and probably already have a restoration thread for the Dahlquist.
This thread:
http://www.audiokarma.org/forums/in...dq-10s-in-da-house.513177/page-2#post-6680914
has a parts list for a recap.

 

@spwath , it might be worth seeing if this seller would part with individual components...

http://www.canuckaudiomart.com/details/649391470-dalquist-dq10/

 

Gone!

 

Many months later and I redid the grill cloth on one.
Going to do the other tomorrow.
Probably going to sell them, but not necessarily.
Im surprised at how good the new cloth looks.

This top part was a bit tricky. Had to remove a wood piece to put the cloth under it, then nail it back down.

 

It's best to keep coils away from ferreous metals. Even a single iron screw in the vicinity will affect it's L.
Also, keep multiple coils at the 90 degree angle from each other. For 3 coils, one in x, y, z direction. Generally, looks good to me. If you can measure speakers, you can see how it's behaving. That's what I'd do. If it works as it should, I say leave it be.

Good job on the front mesh

 

Btw, those look like film caps. You might not need to replace them if you’re on a budget. Generally those age fine. If you want an affordable replacement, try the Cornell Dubliner 940C and 942C type polypropylene film caps. They were the best sounding of the dozen or so regular film caps I tried. They were nearly as good as more expensive Auydyn Plus. At $4-6/ea you shouldn’t be too far out of pocket.

And if you need either 3 or 3.3 uF, I have some I can send you

 

Thanks for the info, but I sold these a while ago for $400. $100 more than my asking price!