DB-25's: Crimp vs Solder?

Posted: Fri Aug 22, 2008 12:55 pm

I'm building a project studio using isolation tape, drywall and Green Glue. I have a 16-channel snake cable I'd like to run in the wall between my main room and my iso room so the iso room could be used as a control room if need be. Each room would have two female DB-25 connectors wired to the Tascam standard. The snake has an extra channel so I could wire the missing pin (pin 13) and have a complete point-to-point bus.

I've soldered 14 out of the 50 connections and - what a mess! I see cold (looking) joints, near short circuits (although adjacent pins are so far testing isolated) and massive burning/melting of insulation.

Then I see these crimping solutions. My recording instructor (and mentor on this project) worries about oxidation of crimped connections and the pins getting pushed out of the housing on insertion. There is also a slightly more expensive set screw solution: http://www.l-com.com/item.aspx?id=10856.

So what's the consensus on soldering vs crimping (vs set screw) for DB-25's? This has to be done right before the drywall goes up. Thank you much!

Posted: Fri Aug 22, 2008 2:20 pm

I absolutely recommend soldering. Soldering is sort of like knitting. You don't make a great-looking sweater or pair of socks on your first try. It's an art form! Flux is very important in making solder flow smoothly, along with proper soldering technique & heat & heat sinking. Later, for aesthetic purposes, the flux can be cleaned off, if you don't like the way it looks. But not necessary. "Blobby" looking cold solder joints are NFG. Melted insulation is even worse. Crimping? Don't go there. It's like the directions to Carnegie Hall when it comes to soldering. I hope you know the directions? In the good old days, you'd purchase yourself a Heath-Kit, Knight-Kit or, DYNACO Kit (or all three on multiple occasions like I did). You'd get really good really fast or it wouldn't work. So practice on something else before you kill your connectors & wiring. You're in too big a hurry. If you screw up sticking things in your wall, you're going to be tearing out walls! Practice Practice Practice.

You know you're alive with the smell of molten lead & burning rosin in the morning! Mmmmm mmmmmmm, yeah!
Ms. Remy Ann David

Posted: Sat Aug 23, 2008 7:50 am

Soldering would be my first choice.

There is a very nice unit which you may want to purchase if you do a lot of this type of work. It is called a resistance soldering station and works well. It has a big transformer, a hand piece with two slender probes coming out of the hand piece and a foot pedal. You put the probes on either side of the pin you are soldering (no heat is generated) you when push down the foot pedal and the pin is heated up by the resistance that it generates between the two probes, you add solder and the connection is made with no harm to the other pins. http://wassco.com/Departments/Soldering-and-Desoldering-Equipment/Soldering-Equipment/Resistance-Soldering--American-Beauty.aspx The other NECESSARY piece of equipment is an anti wicking tweezer that you can put around the insulation of the wire to hold the wire while soldering so the insulation does not melt. http://www.twacomm.com/catalog/model_AWXX.htm

Best of luck!

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