buzuddha

DQ-10 Crossover Rebuild - ready to solder - Help!

11 posts in this topic

Hello all!

I restored the woofers on a pair of goodwill dahlquit DQ-10s and have enjoyed them for about 2 years. I finally got the gumption up to rebuild the crossovers from scratch using some serious components. I am a total novice on electronic circuits, but have a basic understanding of how to read a circuit and soldering. 

As of now I have glued all the components in place and would love any commentary about fixing it all in place with the solder. Attached are progress and the schematics I've run through trying to put this together. I'll add a bill of parts tomorrow and some labels. 

 

Here is a link to the progress and originals. You will see the woofer and mid woofer circuits are on a separate board as the mid, tweeter and supertweeter:

https://goo.gl/photos/gE34pwmCvZrYC8W9A

 

Thanks for any help!!!!

DQ10A.pdf

DQ10 CO schematic.jpg

DQ10 CO schematic2.jpg

Slide1.jpg

Slide2.jpg

Slide1.jpg

Slide2.jpg

Slide3.jpg

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Here's the bill of materials. I've updated the attached photos to include the assignments for the components:

 

Part Number Description Qty Units Price Total Xover Part
260-194  Black Perforated Large Hole Crossover Board Pair 5" x 7" 2 Pair $4.80 $9.60 Board
027-124 Audyn Cap Q4 82uF 400V MKP Foil Capacitor 2 EA $19.62 $39.24 C1
027-578 Solen 16uF 400V Polypropylene Capacitor 2 EA $9.29 $18.58 C2
027-117 Audyn Cap Q4 8.2uF 400V MKP Foil Capacitor 2 EA $4.06 $8.12 C3
027-236 Dayton Audio PMPC-6.2 6.2uF 250V Precision Audio Capacitor 4 EA $4.93 $19.72 C4/C5
027-238 Dayton Audio PMPC-6.8 6.8uF 250V Precision Audio Capacitor 2 EA $5.19 $10.38 C6
027-900 Jantzen 0200 0.10uF 400V Crosscap Capacitor 2 EA $1.20 $2.40 C7
027-462 Jantzen 0506 0.15uF 1200V Z-Superior Capacitor 2 EA $10.84 $21.68 C8
255-424 Jantzen Audio 1.2mH 15 AWG Air Core Inductor Crossover Coil 4 EA $16.39 $65.56 L1/L2
255-418 Jantzen Audio 0.82mH 15 AWG Air Core Inductor Crossover Coil 2 EA $14.06 $28.12 L3
255-024 Jantzen Audio 0.20mH 20 AWG Air Core Inductor Crossover Coil 2 EA $5.25 $10.50 L4
255-036 Jantzen Audio 0.50mH 20 AWG Air Core Inductor Crossover Coil 2 EA $6.40 $12.80 L5
017-4 4 Ohm 20W Resistor Wire Wound 4 EA $0.98 $3.92 R1A/R1B
015-4 4 Ohm 5W Resistor Wire Wound 5% Tolerance 2 EA $0.48 $0.96 R2
016-5.6 5.6 Ohm 10W Resistor Wire Wound 5% Tolerance 2 EA $0.64 $1.28 R3
015-5 5 Ohm 5W Resistor Wire Wound 5% Tolerance 2 EA $0.48 $0.96 R4
015-3 3 Ohm 5W Resistor Wire Wound 5% Tolerance 2 EA $0.48 $0.96 R5
004-30 Dayton Audio DNR-30 30 Ohm 10W Precision Audio Grade Resistor 2 EA $1.38 $2.76 R7

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So how did this turn out?  I just picked up a pair at an estate sale last week.  Replacing the foam surround on the woofers this week.

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Welcome to CSP buzuddha and Jeffh!

There don't seem to be a lot of Dahlquist guys here so you may not get a lot of feedback but keep trying!

Buz, that's a fantastic GW find and your new crossovers look fantastic! Very neat and professional work. I don't really understand your question; 

On 1/22/2017 at 11:04 PM, buzuddha said:

would love any commentary about fixing it all in place with the solder.

Just twist the leads together according to the schematic and solder? Your skill level seems high so I'm unsure what you are asking.

-Kent

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Nice!

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These turned out great!

I was asking for feedback because this was literally the first time I've ever soldered anything together. Had to go through and triple check all the connections.

I didn't get any feedback so I said "screw it", and jumped right in. The speakers sound incredible. The treble control knob on the back now has a very noticeable effect on the sound. Also, I would say the speakers are sounding great, but I changed out my preamp at the same time as the crossovers, so it's hard to know what is due to what. But in total everything sounds great now.

 8847773864204095995%253Faccount_id%253D1

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i like it.  Great clean work.  Soldering is all about jumping in.  A little practice on not so important things is of course best.

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You put some real effort in your crossover rebuild and used good quality parts!  I am in the process of rebuilding a dq10 crossover.  I was going to replace all parts with better quality parts but ran into a snag.  As I was measuring the inductors with an ohmmeter I noticed that some intentionally had high resistance, by design.  The inductor on the super tweeter was extremely fine wire and measured around 6-7 ohms.  If I replaced it with the a new inductor of the smallest gauge wire available it would be less than 1 ohm.  This would change the balance and sound of the speaker.  I decided to use the original inductors as they all have the correct DCR.  I am replacing all capacitors and haven't decided if I will replace the resistors yet.  The inductance in the original resistors could be different than what is available today.  This project is not as easy as it looks.

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