Re: New Builder Buying Blues

[K3yPr0gg3r]

Hi,

If I'm repeating an ongoing forum question, I apologize. I did a search, and found nothing relating to what I'm about to ask. I haven't purchased passive parts, (resistors/Caps), for the 8 PCB's I've already bought, and THANK GOODNESS I haven't! I'd have wasted money. It seems that an MPSA18 transistor or a 1n5817 diode are just what they are. However, a 2m2 or 180k resistor, or 100n/470pf/22uf capacitor aren't what they seem to a new guy.

As a new builder, I want to do quality work, and I rely on the build documents that come with the PCB I'm about to buy. I had the good sense to email one of my main suppliers with links to components I was planning on getting, and I'm grateful I did...Because all my decisions where WRONG!

Build docs. Don't tell you that the 22uf electro cap. needs to be 5x9mm and 25VDC, (not 5x11mm and 50VDC). Is there a page somewhere that lets new builders know what limits PASSIVE components need to be in order to fit the enclosure, and properly function when the stomp is pressed?

Thanks

[flanagan0718]

I can certainly understand the confusion on some, if not most parts. I still from time to time order ELE caps that are too big or the lead spacing is off. It happens to the best of us. Honestly ordering from Tayda the first few times helped quite at first. It will give you a few parts to measure and compare to. It also helps that the parts are pretty cheap too.

I only recently started ordering somethings in bulk. Honestly Mouser scared the CRAP out of me at first. I still don't order from them but that's beside the point. Here are a few things that are pretty common for parts

Box film cap lead spacing = 5mm
Electro Cap lead spacing = 2mm or 2.5mm
Electro Cap Diameter = 5mm or 6mm
Pot Shaft Diameter = 6mm - 6.4mm

Hope this helps. I have also see some people post Mouser parts list links before. You might be able to search for them. Good luck.

-Mike-

[lincolnic]

Also, 1/4W resistors will always be the same size. Just make sure you're ordering through-hole and not SMT!

[BrianS]

What Mike said will help a lot.  When I first started most everything I built was in a 125b enclosure. That gave me plenty of room to do whatever I needed to do.  As my proficiency advanced I moved to almost all 1590b enclosures.  Most build docs will tell you what enclosures to use. If you are adding a lot of mod switches the enclosure may have to go up in size.  Most of the components I bought when I first started came from Tayda (not so much now).  I mostly use 50v electrolytic up to 100uf with a length of no more than 5x11mm. Once you get past 100uf you sometimes have to be careful because they increase in height and width. You can always lay an electrolytic on its side in most cases if it is to tall.  Transistors legs can be cut or again they can be bent over other components.

[midwayfair]

There are some assumptions you can make, which Mike provided in his list. But more to the point, there are some assumptions that manufacturers make: that a part for a specific function will be a certain size on any PCB designed to accept a part like that. Nearly all 25V electrolytic caps are identical dimensions, except ones that are a special series, like Panasonic's and Nichicon's mini electrolytic capacitors that we use in the 1590A projects. 1/4W resistors are all the same size because manufacturers don't want a company to be unable to fit their part into a product. Film capacitors (whether box caps or Panasonic ECQ caps) for the most part are the same size at any particular capacitance and voltage rating for the same reason, but there are physical limitations where more capacitance requires more physical size.

----

I'm going to suggest that ordering from a place like Smallbear (or your continent's equivalent if you're outside N.A.) when you start out is the best way to go. The parts are known to be genuine, most often guaranteed to be in spec, they are always PEDAL PARTS (that is, the size that are standard for pedals), and they don't have much that you can order that isn't the correct part.

I know Brian either links to or provides the part number for anything in his bills of materials. Most projects suitable for a beginner I've seen specifies things like "1/4W resistors," "63V box caps," "16V/25V electrolytic capacitors," etc., which are standardized parts. I had a look through the "Noob" labeled projects on the MPB projects page and the wattage/voltage/pot size is provided. Ordering parts from every parts supplier in the FAQ EXCEPT mouser will pretty much guarantee that the part is the right size if you use even that basic information.

We've all made mistakes ordering parts because we didn't understand the instructions fully. But when you design project documents, there is a limit to how detailed you can get about the parts to be ordered, because quite frankly the assumption is made that by the time someone has progressed beyond projects specifically labeled as designed for beginners that they will know that resistors and capacitors from the common suppliers for those ratings are always the same size. If the builder is ordering from a place that isn't pedal-specific like Smallbear, then the person designing the project can't anticipate every builder's particular gaps in understanding.

[Martan]

I keep going back to this page for links (no affiliation):

https://aionelectronics.com/resources/where-to-buy-what/

Has been solid advice thus far.

Marty

[rullywowr]

Good advice throughout, especially Mike's list. 

I have found that 11mm should be the max height of just about any component in a build (especially caps) if you want the lid to fit on properly in a 1590B. 

As I progressed in building and designing my PCBs, my most recent layouts are designed so the electro caps can be shorter than 11mm..and a bit larger in diameter.  For example, I make the 47uF layouts accept at least 6.3mm dia cap.  With 100uF electros, I try and make my layouts take 8mm diameter caps.   Of course, if you want to use caps which are taller and smaller diameter, that will work OK too.  The shorter caps look neater to me and also have the advantage of being used in baby builds (1590A).  Shorter caps allow neater layouts at the expense of a little more PCB real estate.  Personal preference I suppose 

I created a basic document a while back which should help those unfamiliar when selecting parts:
http://www.rullywow.com/wp-content/uploads/2013/12/What-Components-do-I-need.pdf

[K3yPr0gg3r]

Thank you to all who posted. I've got to say, DIY pedal forums are some of the "user friendliest" I've ever run across! I'm also a musician and mixing engineer, and there are some hostile forums out there....so thank you. Again, haven't started ANY builds yet. I'm just gathering information, taking a few soldering classes, some basic electronics classes, and posting on forums like this one.
I've got 4 PCBs from Ben, 3 from Jacob, and 3 from TH Elec. Not to be a cocky Noob, but the actual PCB population looks fairly straight forward...just follow the + or - signs, socket the ICs and transistors, and follow the 3PDT diagram to the letter...(unless using one of the breakouts available out there). However, I get the feeling that those are pretty build specific because of the way they're manufactured, (i.e. Ben's breakouts for his PCBs. Wouldn't sync with a Mudbunny build let's say...yes?)
One last observation. All, I think, of the builds I've ordered are PCB mount for the Pots/Switches. I've had some confusion with visualizing which side of the PCB these are attached. I'm looking at TH C.E.'s "Jenny Greenteeth", and it looks like I solder to the populated side of the PCB, and the Pots are on the opposite side of the components, (meaning the components will be facing DOWNWARD once the box is complete). Is that correct? Again, Thank You!

[matmosphere]

The breakout boards would be compatible, you just need to read the labels carefully to make sure everything is connected properly.

As for your other question I'm a little unclear as to what you're asking. You should solder the components by applying solder to the opposite side of the board than the component is actually on. Some people do both sides for resistors, but it's not necessary. The pots and switches mount on the opposite side of the components and solder is applied to the pots and  switches on the side with the components.

Hope that helps, it's not the most eloquent description