First pedal build - making a RAT clone pedal from a kit

Megii

Figured I'd start this thread now, while I'm still getting the various bits I need together. I have some soldering experience gained over the last 8-ish years modding guitar wiring and putting together partscasters. But I've not done any work with printed circuit boards or any other electronics, so I really consider myself a fresh-faced newby to the world of pedal making. Anyhow, I'm starting this thread to document my experiences (good or bad) as I attempt to put together a RAT clone type pedal from a kit. Probably seems ridiculously straight forward to those with more experience, but at this point the idea feels a bit daunting to me. We'll see how it goes though.

So far I've bought/ordered a couple of things:

Variable temperature soldering station from Maplins: http://www.maplin.co.uk/p/60w-mains-lcd-solder-station-a55kj

and the kit itself, from Fuzzdog's Pedal Parts: http://shop.pedalparts.co.uk/Rodent_distortion/p847124_7398084.aspx

- I'm going for a 4 control version with the Ruez mod option, and a switch for vintage (silicon) and turbo (LED) clipping modes. I've opted for a black powder-coated enclosure, and some nice orange control knobs, which should look cool and a little different, not that this is all that important.

I did consider also buying kit for a Klon buffer unit, just to have something fairly simple to start with and gain practice on, but I do already have a decent buffer on my pedal board, and I don't really need another. I may get myself a bit of strip board, and practice my soldering technique a bit on that before starting on the kit though.

A few other bits of kit to buy, which I hope to get sorted this week, but no rush, and I'm going to take my time and try to do as good and careful a job as I can, and hopefully have a nice working pedal at the end of the process.

english_bob

My top tip for starting with kit building is to start by sorting the components. It'll make things much simpler when you start putting it together if you know for sure that you've got all the parts you're supposed to have, and it stops you getting confused between similarly labelled components.

This isn't mine, and clearly isn't for a pedal, but the principle is the same:



I can kind of understand why people suggest starting with small kits, but there isn't really any difference between building a small kit and a big one except that the process of "find component, place component, solder component, repeat" goes on for longer, and has more potential for dry joints and misplaced components.

Go slow, double check everything and it should all go smoothly.

Megii

Appreciate the reassurance @english_bob thanks. And I think with some components, another point is make sure they go in the right way around.  

english_bob

Megii said:

Appreciate the reassurance @english_bob thanks. And I think with some components, another point is make sure they go in the right way around.  

Not always. You do need to make sure that diodes, electrolytic capacitors, transistors and any IC chips are the right way round, but resistors and non-polarized capacitors (ceramics and box-type) can go in either way. Results from getting this wrong can vary from the singularly unimpressive (nothing happens, but your pedal won't work) to the explosive. 

It's almost always made very clear in the component markings or design (polarized capacitors are labelled, modern-ish transistors are usually flat on one side, older ones often have a little tab on the side, diodes have a stripe at one end) whether it's important to orient them correctly, and if so which end is which. Most of the kit makers design their PCBs so that it's obvious which way round components should go too. They'll often have one round solder pad and one square, "+" and "-" symbols or a little visual depiction of the component- a diode as a rectangle with a line at one end to indicate the stripe on the component, or a transistor shown with one flat side.

Again, go slow, pay attention, double check before soldering and it'll all be peachy.

ewal

Good luck! It's pretty simple - I've built a few pedal parts kits. The auxillary board for the foot switch is a good idea too. My issues are with fault diagnosis once the build is complete. Currently my diagnostic skills just aren't up to scratch. Working on it though... I ventured on to diystompboxes.org for tips - need to work out how to measure voltages at various points on the board which appears to be info required in order to take diagnosis beyond checking for dry solder joints.... I'll get there in the end...

ewal

Another tip - solder low lying components first - resistors, then diodes, then IC's, then caps, etc

ewal

Regarding polarity - Pedal Parts instructions always make this clear

english_bob

ewal said:

Another tip - solder low lying components first - resistors, then diodes, then IC's, then caps, etc

Yep. Definitely a worthwhile tip. Many diodes are smaller than resistors though, so it might be worth starting with those. 

ewal

Soldering - keep the tip well tinned, but without have a glob of solder on the tip - I've inadvertently managed to drop solder and close holes because of this. Also increases the chances of bridges between adjacent points.

Also, apply heat to the solder pad and component wire, then apply solder to other side - that way you get a quick and well formed connection without too much solder.

Megii

Thanks for the further advice @ewal and @english_bob - all good stuff, and all will be taken account of. It's the sort of stuff that really does help compensate for a lack of experience, at least a bit, and might make the difference between a successful project and one that goes a bit pear-shaped.

jonnygreentrees

another tip - socket transistors if possible and if not use a heat sink (crocodile clip) on the legs of diodes and unsocketed transistors 

Megii

jonnygreentrees said:

another tip - socket transistors if possible and if not use a heat sink (crocodile clip) on the legs of diodes and unsocketed transistors 

Thanks @jonnygreentrees - maybe a daft question, but if I'm using a croc clip as a heat sink when soldering a joint, where exactly is it best to clip it? i.e. would it be on the component side of the board, between the component and the board? If so, I guess it's not then possible to finish with the component flush to the board, because room has to be made to clip on the croc clip. My pedantic side is coming out here, but hope you understand what I'm on about.  

jonnygreentrees

Megii said:

jonnygreentrees said:

another tip - socket transistors if possible and if not use a heat sink (crocodile clip) on the legs of diodes and unsocketed transistors 

Thanks @jonnygreentrees - maybe a daft question, but if I'm using a croc clip as a heat sink when soldering a joint, where exactly is it best to clip it? i.e. would it be on the component side of the board, between the component and the board? If so, I guess it's not then possible to finish with the component flush to the board, because room has to be made to clip on the croc clip. My pedantic side is coming out here, but hope you understand what I'm on about.  

Nah solder side on the leg you are soldering, maybe a cm or less up the leg. This reduces the risk of frying transistors and diodes with too much heat

jonnygreentrees

also a digital multi-meter is super useful for troubleshooting and checking the values of resistors 

Megii

jonnygreentrees said:

Megii said:

jonnygreentrees said:

another tip - socket transistors if possible and if not use a heat sink (crocodile clip) on the legs of diodes and unsocketed transistors 

Thanks @jonnygreentrees - maybe a daft question, but if I'm using a croc clip as a heat sink when soldering a joint, where exactly is it best to clip it? i.e. would it be on the component side of the board, between the component and the board? If so, I guess it's not then possible to finish with the component flush to the board, because room has to be made to clip on the croc clip. My pedantic side is coming out here, but hope you understand what I'm on about.  

Nah solder side on the leg you are soldering, maybe a cm or less up the leg. This reduces the risk of frying transistors and diodes with too much heat

Cheers, got it.

jonnygreentrees said:

also a digital multi-meter is super useful for troubleshooting and checking the values of resistors 

Already have one - not a particularly posh one, and it doesn't do capacitance, but hopefully OK for what I need?

jonnygreentrees

Megii said:

jonnygreentrees said:

Megii said:

jonnygreentrees said:

another tip - socket transistors if possible and if not use a heat sink (crocodile clip) on the legs of diodes and unsocketed transistors 

Thanks @jonnygreentrees - maybe a daft question, but if I'm using a croc clip as a heat sink when soldering a joint, where exactly is it best to clip it? i.e. would it be on the component side of the board, between the component and the board? If so, I guess it's not then possible to finish with the component flush to the board, because room has to be made to clip on the croc clip. My pedantic side is coming out here, but hope you understand what I'm on about.  

Nah solder side on the leg you are soldering, maybe a cm or less up the leg. This reduces the risk of frying transistors and diodes with too much heat

Cheers, got it.

jonnygreentrees said:

also a digital multi-meter is super useful for troubleshooting and checking the values of resistors 

Already have one - not a particularly posh one, and it doesn't do capacitance, but hopefully OK for what I need?

you need one that measures resistance, should be an Ohm symbol 

Megii

Yep, it certainly does resistance @jonnygreentrees so one less thing I need to buy, which is good.

ewal

jonnygreentrees said:

Megii said:

jonnygreentrees said:

another tip - socket transistors if possible and if not use a heat sink (crocodile clip) on the legs of diodes and unsocketed transistors 

Thanks @jonnygreentrees - maybe a daft question, but if I'm using a croc clip as a heat sink when soldering a joint, where exactly is it best to clip it? i.e. would it be on the component side of the board, between the component and the board? If so, I guess it's not then possible to finish with the component flush to the board, because room has to be made to clip on the croc clip. My pedantic side is coming out here, but hope you understand what I'm on about.  

Nah solder side on the leg you are soldering, maybe a cm or less up the leg. This reduces the risk of frying transistors and diodes with too much heat

So that's where I've been going wrong - I've been attempting to attach heatsink on the component side... (without success)

jonnygreentrees

PedalParts kits are pretty reliable, I've only ever had one not work and that's when I got lazy, didn't use a heat sink on the diodes and fried them, then ended up with loads of lifted pads trying to unsolder the board mounted pots to do troubleshooting

ewal

I lifted pads off my Harmonic Percolator build when attempting to desolder some components - things started to get very messy after that... This and inadvertently dropping solder and closing holes have been the most annoying mistakes recently.

english_bob

What soldering irons are you using, @jonnygreentrees , @ewal ? I've never wreaked that sort of destruction using my feeble little £10 Iron (25W?). Never fried a component, never lifted PCB traces...

I have burned a couple of holes in Mrs_bob's tablecloth though, which is arguably worse...