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New member - Dahlquist DQ10 questions

Hello gentle people,

im a retired electronics engineer so I now have time to do some repair projects I've been wanting to do. 
I've wanted to get back into listening to my stereo setup and be able to play vinyl again so I resurrected a pioneer pl 50 table and then got to looking at my DQ10's thinking I'd refoam the woofers, check the crossovers, etc. I've owned the dq10's for over 25 years and never did a thing to them but when I got them apart, I found the woofer surrounds to be in great shape, which I thought was really weird. The guy I bought them from mirrored them and I'm wondering if he then coated the woofer foams and that's why they're in such good condition.
I did find one of the 5" mids has a approx 1/4" tear in the rubber surround. It plays ok but I'm thinking the surrounds on both mids should be replaced. 
I've been doing a lot of reading but see no replacements for rubber surrounds for these.
Anyone know of a source?
Also, I'm driving these with a (about to be recapped) quad 405-2, that is driven by a Mac C27. 
Im thinking even after a recap, the quad may not be up to the task. Thoughts?

Thanks very much

ritamacaw
ritamacaw OP
17 posts
 
Of course I had my reversed. 
Thanks!
ieales's avatar
ieales
1,201 posts
 
Mike,

I owned DQ10s in the mid 70’s. Mirror imaging is a good thing. Drivers outside in my room back then. YMMV. I like to set coherent speakers toed in slightly so they align about 1 foot behind my head. In a narrow room w reflective walls next to the speaker, drivers inside and firing straight back may be preferred.

Ditto pzo tweeter replacement. IMO, they sound better up off the floor and less angled than the stock feet. Today, I’d add a pair of subs, probably XO ≈60-80Hz, depending on the room. Definitely recap with PP to get rid of the electrolytics, ceramics. I don’t remember the details, but I changed the woofer XO / damping / ???. You might be able to turn up something similar.

IIRC, I had Ampzilla, maybe a big Yamaha, but also listened with several amps belonging to friends. The original 405, APT 1 & other era of similar power drove the DQs easily.

As far as recapping the 405, the service manual is available @ HiFi Engine
https://www.hifiengine.com/manual_library/quad/405.shtml

The parts lists does not indicate the capacitor types. Any ceramic, mylar should probably be upgraded with PP or PS. The WIMA MKP are well regarded PP https://www.tawelectronics.com/wima/WIMA_MKP_10.pdf


-- Al (also a retired EE)
Al, we never ’retire’.
Our caps dry out, our resistors drift, ours tubes fade...
ritamacaw OP
17 posts
 
Thanks for that information.
I've ordered the 80uf caps for the crossovers. I may end up replacing others. 

Im thinking after the cap changes in the crossovers, the mid surrounds getting replaced and recapping my power amp, I'm going to just listen to them and not mess with the woofers for now unless I hear some strange stuff out of them. 
Have no idea if refoaming them would make any sonic difference being they seem so pliable after all these years. 
curiousjim's avatar
curiousjim
4,221 posts
 
I replaced the tweeters with Decca ribbons. It made a wonderful change!  
Best

JD
ritamacaw OP
17 posts
 
Did you replace the tweeters and unplug the super tweeters or replaced both tweeters in each?

thanks,
michael
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