SMD to Through Hole

[sr1200]

Just wanted to know if anyone has ever soldered a couple leads onto a SMD component and used one as a through-hole.  Im having a horrible time finding certain resistors as through-hole, but can find them easily as SMD.

 

[abechap024]

Yikes! I tried to do that once, ordered a SMD resistor instead of a through hole. It was very hard from what I remember. The main trouble being that the little resistors or caps want to stick to the tip of your soldering iron like they just love being burnt to a crisp. Then if you do manage to get one lead on one side, when you go to the other side it re-flows the solder on the other side and the first lead falls off. Maybe their is an easier way but I couldn't figure it out.

What resistor values are you looking for? There is a place in china that will make a custom order of whatever value you need if you order 1000...which comes out to about 15 bucks.

 

[sr1200]

i need 2 resistors lol.  6.8k but .1% tolerance. None of my usual haunts seems to stock them or if they do they're out of stock for the next 6 months.

 

[JohnRoberts]

After getting used to SMD technology this doesn't seem as crazy as first sounds.

You could solder one end of the SMD resistor to one pad on the solder side if single sided PCB, and then a short wire jumper from the other side of the resistor to the other pad.  Of course, don't buy the smallest resistors that may be way too small to work with (02x03 or something insane like that).

But it still sounds a little crazy.... surely you can find TH parts still...

JR

 

[abechap024]

would buying a 6.81K at 1% tolerance get you there?

http://www.mouser.com/Passive-Components/Resistors/Film-Resistors/Metal-Film-Resistors-Through-Hole/_/N-7gz41Zscv7?Keyword=6.81k&FS=True


and there looks to be some 6.81K at .1% tolerance too in there if its what you need. Mic pre I suppose?

Best,
Abe

 

[Biasrocks]

You simply need to match the two phantom power resistors as close as possible, they don't have to be exactly 6K8.

Buy a bunch and match them up.

Regards,
Mark

 

[sr1200]

Bias and abe, i was thinking the same thing, to just get a whole bunch and match them as best as possible.  And yes its for Colins ez1073 project.

 

[zephyrmic]

I have used SMD 5G resistors in some of the mics I have built with good success. I found that using thin multi-strand PVC insulated wire for leads is useful, because they can be bent without damaging the end of the resistor by bending a solid lead. I had a failure where bending the lead broke off the whole solder pad on the end of the SMD resistor. So I made up a soldering jig by screwing a spring metal clip (stainless steel that I had available) to a piece of melamine faced MDF board, clipped the SMD resistor under that, tinned the multi-strand lead, and then soldered it to the resistor. Repeat process for the other end. Worked like a charm! Just needs care, and a good magnifying glass helps as well. Then if need be, clean off the solder flux from the resistor.

As to 6.8K phantom power resistors, when I built an outboard phantom power supply, I bought some 1% through the hole resistors and matched them with my DMM, and that worked really well. Hope that info helps.

Kindest regards,

zephyrmic

 

[PRR]

> i need 2 resistors lol.  6.8k

Worst-case dissipation is 0.34 Watts. You sure those teeny parts are good for it? Especially in-air instead of flat to a heat-sucking PCB?

Hand-sorting 5% into 1% pairs always seemed good-enough to me.

 

[sr1200]

I wound up ordering 200 of the resistors at 1% to match some... was $4 for 200 of em or $3 for 20 of em.... ill just match them as close as possible, then NEVER have to order that value of resistor ever again  8) 8)

 

[gemini86]

A few years ago I bought 100 each of e12 standard resistors from 100r to 1 Meg, haven't really needed to buy resistors since. (excepting high wattage parts)

 

[JohnRoberts]

You can further improve the quality of match by using 4 parts, two pair of two in series-parallel, so the R is the average of the 4. This will also increase the power handling if marginal... while it may not look pretty.

JR

 

[sodderboy]

If you look down this post I have a pic of my matching jig.  I made it just for a 6k8 job, and now use it for many things.
Mike