Project Effects: SMT-o-rama

When I ordered my kits from NightFire I did not know what SMT stood for. Now I do. It’s surface-mount technology. Some of the parts are barely bigger than a sesamé seed. I wondered why they advertised loupes all over their site. I arrogantly assumed it was because old folks were doing electronics and with my fantastic eyes I’d have no need of such cripple-ware (oh, Jody, it’s just colorful speech, man!). Instead I discovered I was lucky to have a good powered pocket magnifying glass in my dresser because even with it I can barely make out any of the writing on these things.

Ah, yes. Live and learn.

Wasted money, I thought. But they are great parts is the thing. Much better gain and signal to noise ratio than the bigger parts I got. Why I ordered them. So I must try to use them. I have no copper boards or etching chemicals though and I’m not that interested in trying right now anyway. So, the solder. Here’s the first stab.

Can you even see it? Here’s a close-up picture after all three wires were attached. I need to have it on wires so it can be used in prototyping on the breadboard. The trick is–

• Get the wire hot, not the SMT (an MMBT5089 transistor in this case). I used a 15 watt solder iron.
• Put a little solder to the wire; keep it hot with the solder iron against it.
• Move the SMT contact point into the solder and simultaneously remove the iron.
• Hold it very still and blow… hmmmm, I’ve heard this advice before. No! given it. Yeah, given it, that’s the ticket.

The wires above are for the breadboard. If doing this for a real circuit, high guage stranded copper wire—or just soldering directly to the board—would be the right choice.

For perspective here it is with the other wires and a guitar pick. There is a pink circle around it to help you see where it is.

The gain and voltage requirements were different from the 2N3904 and NPN friends I was playing with so I had to swap out caps and resistors for awhile till I got something nice, but it is nice. I now have two different custom modifications of the Electra Distortion circuit and I think both are improvements over the original.

I picked up some more parts and will definitely do this one in an enclosure. Still have to manage to do a DPDT switch and add in a LED before I can do a complete effect properly.

Might all be a week or two away. It’s exiting to consider how small the effects board can be with the SMT parts. Could put 5 different effects into a regular pedal enclosure. It would only be limited by the space needed for pots.

Here is a new schematic of my own for the effect. This is probably not the one I’ll build because it’s not the transistor I like better, but the drive/distortion on this is adjustable and much smoother—to me—than on the original. I didn’t prototype it with the volume pot so 100k might not be the best value; also the drive control should probably be a 2k fixed resistor in parallel with a 500k pot (those values are not quite right) wired backwards to get something close to 2k–50k adjustable resistance in there.