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Posted

I have some basic electronics awareness, and I'm now reading up on building a few DIY effects (booster & distortion for starters), but ones that I'd like to mount inside the guitar. As a space saver, I'm wondering about these "mini" components that I see soldered onto mini PCBs; you know, transistors and ICs that look like little spiders, resistors & caps that look like tiny rectangles with solder on each end, etc etc.

My questions are:

A- has anyone worked with these, and are they OK to use in my application?

B- are the mini components available from suppliers like Digikey etc?

C- can you get printed prototype mini-PCBs made?

Have a look at the EMG Afterburner PCB and you'll see what I mean. I've got magnifiers, tweezers and a fine-tip soldering iron, so I'm ready to make a go of it if the parts can be had.

TIA

Erik

AB.jpg

Posted

Yup, they are called surface mount devices. They are a bit tricky to solder by hand but it certainly can be done.

Here's a pic of one that I did a while ago:

tonectrl1.jpg

Take a look at pcbexpress for getting boards made. You can get a few small boards for about $50 to $60. It's hard to be cost effective in small quantities though.

Also - if you decide to use them - buy the components before you have the boards made. You need to be sure of the component sizes. With non-SMT devices, you can get away with getting the hole spacing wrong (just use more of the leads) but when all you have are pads and a rectangular block, the spacing needs to be right.

Posted

He, he, too lazy B). I just wanted to get the overall size of the board to approx. what that is. I could have made it smaller by using SMT resistors but I didn't think that was worth the hassle. I actually use a big honk'n 1/4 in there also (I screwed up my order from mouser :D ). The caps were the biggest components (if I were to use non-SMT devices) so those were the ones I went after.

I did another board with a SMT opamp and that was challenging. I don't have surgeon's hands so that didn't help matters.

There's another place called pad2pad that supposedly populates comoponents for you as well as ethching the boards. I bet it's too costly for small guitar projects but maybe it's worth it for shaky handed people like me?

Posted

Did you etch your own boards, or did you have them done? My efforts at using PNP and photo-resists to etch my own boards have been less than encouraging, so I'm looking for a cheap way to get soeone else to do boards. The only way I can see making PCB Express economical for small projects is to use their miniboard service, and "panelize" your boards - for instance, 20 of my JFET preamp layouts will fit on their miniboard, so 3 miniboards at $59.00 total comes out to about a dollar a preamp for 60 boards. Obviously, I wouldn't have to reorder any time soon, and I would have to cut up the boards myself, but if the sheet metal shear won't handle that, I'm sure my "diamond" wheel on the Dremel will. I'll let you know how well it works when I finally muster the courage to try it out! :D

Posted

Lovecraft, I was thinking exactly the same thing. I've already got a few friends who want an afterburner-sized booster for their axes if I make one, so that's exactly what I was thinking.

But if you hit on a cheaper alternative, let us know.

Posted (edited)

Here's what I was thinking when ordering boards, get as many boards as you can fit onto one piece, i.e. maybe throw a tubescreamer in there, a rat, a Fuzz Face, some different boosters, a compressor, etc. etc. You will still get three of each board, but with some effects (Tube Screamer, Fuzz Face), you could easily use them to make different flavors of the effect (maybe make one silicon fuzz face, one germanium fuzz face, and one hybrid, etc). Or maybe a few of us could go in together?

I would like boards for the following:

Fuzz Face

Tube Screamer

Marshall Blues Breaker

Ross Compressor (or Orange Squeezer)

simple boost/buffer

Of course, I can buy these from GeneralGuitarGadgets.com or Tonepad.com, but the average price is about $12.

Edited by javacody
Posted (edited)

Those layouts (FF, TS, compressor, etc.) all take up a lot more board space, so you'll only be able to fit 2 or maybe 3 on a miniboard. If you add anything to the cost for your effort, you've already reached GGG's prices, and their layouts are proven! Unless you're making boards for your own design, it's probably cheaper (and a helluva lot easier) to buy the boards. You can always download their templates and do the toner transfer thing, and etch and drill your own, but again, it depends on what your time is worth, and you'll need to buy at the very least several #65 drill bits (you'll break a bunch) and a collet that will hold them for your drill press.

A group buy is a great idea - all you have to do is find a bunch of people who all want exactly the same thing. B) If you can find a large group, you can get some serious discounts! Just take my advice, and have everybody pay up front before you order several hundred. :D

Edited by lovekraft
Posted

Layout question...I know that sometimes you can run into issues when components are too close together (I don't know which components & what the problems are exactly...but...). If you take a GGG layout and scale it down to substitute and use SMD components, can you run into problems?

Posted

Scaling down an existing layout should eliminate most layout problems, but it's no guarantee, since components and traces will of necessity be closer together. As soon as I can get my ducks in a row, I'm going to buy a copy of RG Keen's book on designing boards, so I'll know more about the issues involved (for those of you who just said, "Huh??!?", RG is the host and author of GEOfex, and one of the resident gurus over at Aron's DIY Stompbox Forum). Generally, if you can keep inputs and outputs well separated, and avoid ground loops, layouts aren't that critical, except in really hi-gain circuits where oscillation can be a problem (at least that has been my experience - I'm no expert!).

Posted

I had a part time job, back in the mid '80s, assembling SMDs. It was kind of interesting. They used ceramic substrates and then screen printed the conductive traces, the resistors, and the non-conductive masks.

My job was to look glue on capacitors and ICs. The caps used conductive epoxies and the ICs used dielectric epoxies. The ICs were harder to install than the caps. They were easier to damage, had a specific orientation and location they had to be in. We used a slender vacuum stylus to pick the IC out of it's tray and then put it on the drop of epoxy.

Automated machines would ultrasonically weld gold wires from the IC to the board it was on. The machine would identify landmarks on the IC and landmarks on the board. It was able to correct for small misalignments and took less than a second for each wire. There was another machine that used a laser to trim a slot in the printed resistor to precisely set it's resistance value.

Posted

futurlec.com they make nice pcb's are quite cheap done rather well two things to keep in mind

1. check double check and triple check your layout. then send it to someone else to check for you.

2.send money order or payment right away.

they are harder as sin to get to answer questions so its best to do your home work first and just let them do what they do best that way they can just make them and send them to you.

gen 3 of the penguin love was done with their boards and i was completely satisfied i used eagle for its autorouter then i transfered that into expresspcb software and cleaned up a few things i didnt' like from eagle. then i emailed it to them sent out a money order the same day

i got 10 boards for 15usd including shipping. and ihad them 10 days from the day i hit send.

http://futurlec.com/PCBService.shtml

sp

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