Question about substituting components

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Junk
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Question about substituting components

Post by Junk » Tue May 05, 2020 4:13 am

Hey guys, I'm totally new to DIY, done one kit before but now I'm ordering a BOM for the first time, and I've got a question which has almost definitely been answered somewhere in this forum, but I couldn't find it with the Search function.

I want to order components for a module and one component is obsolete and another 3 are on back order until July.

I'm wondering what I can substitute these components for, and will this have a detrimental effect on my module. As well as sourcing the components for this module, I'd also like to know more in general what I have to look for when substituting one component for another.

I guess what I'm looking for is a Dummies guide to substituting components. Any tips, tricks or links which people have would be great.

-------

If youre interested, the module I'm looking at is the DIY Delay from Erica Synths and the missing components are:

OBSOLETE
Aluminium Electrolytic Capacitor - Radial Leaded 1uF 25V 85C
https://mouser.com/ProductDetail/539-SN010M025ST

ON BACKORDER
Metal Film Resistors - Through Hole 1K OHM 1/4W 1%
https://nl.mouser.com/ProductDetail/603-MFR-25FBF52-1K

IC & Component Sockets 16P DIP SKT 300 CL LADDER
mouser.com/ProductDetail/571-1-2199298-4

Headers & Wire Housings WR-BHD 2.54mm Box 10Pin Male Straight
https://mouser.com/ProductDetail/710-61201021621

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Re: Question about substituting components

Post by Agawell » Tue May 05, 2020 5:06 am

Ah welcome to the fun and interesting world of component substitution!!!

for the cap take a look here - pretty much any of these will work - I found this page by clicking on the "show similar" button on the page you linked (after duplicating that tab) and then altering the search to as much as possible reflect the specification of the original item

if a component gives a voltage rating then you need to get the same or bigger
it's useful to identical sizes - height width length and lead spacing if possible - so that it will fit

for the resistor you should be able to find everything else identical except for the brand - brand is irrelevant - the ones mentioned in the BOM were probably the cheapest available at the time

for the socket - you do not actually need this - you can solder the ic straight to the board - however, some people like these - try tayda - I usually buy these from there

for the box header - either try tayda - again I usually buy these from there - or just find something like this - but try tayda - this is about 20% the price at tayda

for tayda - always choose the cheapest shipping option - otherwise you get hit for import duty etc - you just have to wait a little - mostly less than 2 weeks
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Re: Question about substituting components

Post by twigathy » Tue May 05, 2020 7:33 am

If you want shrouded headers, I found these on CPC - not actually used them yet (Waiting on PCBs to be delivered), but they should work. Maybe...

https://cpc.farnell.com/amphenol/t82111 ... dp/CN16426

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Re: Question about substituting components

Post by khyber » Tue May 05, 2020 8:40 am

These are questions I still wrestle with, especially with components like capacitors given the variety of types of caps there are in the market. There is an art to substituting certain types of components in a given category, but given my intermediate experience I try to not stray too far from what's outlined in the BOM.

Lead spacing can be one area where compromise is afforded. I would not purchase a bunch of resistors that are differently sized than the through holes on the PCB, but for some components where you're only using a handful, you can contort the leads a bit to make them fit. I had to do this with a capacitor recently on a DU KRPLS build, I haven't tested the module yet but I am pretty sure the component will work in this build. Just make sure the bent leads do not come into contact with any other component's leads or conductive surfaces (especially if sandwiched under another board full of components).

Do pay attention to component height though, again, with this DU KRPLS build, I managed to buy 3 electrolytic caps which were too tall for the build. I'm still using them, just bent a little to the side. Everything seems to fit nicely at this point but I have yet to build the control board and test the unit. Given the circuit bent nature of the KARP/DU KRPLS I am interested to see what results I get from the substitutions I've made (using a few 1% and 5% resistors in the build as well as I had these extra components lying around).

I do get concerned when I see the component the BOM specifies is out of stock or EOL but I have to imagine that following a few specific guidelines on the type of component and size, ratings, etc should lead to a correct match. Some components leave a lot less wiggle room though (transistors, ICs, etc).

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Re: Question about substituting components

Post by EATyourGUITAR » Tue May 05, 2020 8:50 am

here is the new part number for the capacitor

860020672005
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Re: Question about substituting components

Post by BartBral » Tue May 05, 2020 9:29 am

You can always try TME, they have a lot of parts and shipping prices are far better for Euro countries. Shipping is very fast as well. https://www.tme.eu/nl/

Mouser can be a bit of a hassle, if you forgot one little thing... Katjingkatchingcatschiennng! And they ship only after a few days... And you need credit-card, or it will be even more of a waiting game.

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Re: Question about substituting components

Post by Studioalethea » Tue May 05, 2020 10:13 am

Here’s another resistor link for you:

https://www.mouser.com/ProductDetail/Ya ... iJp5LuU%3D

Parts come in different packaging. In this case the “bulk” packaging is out (which is just loose individual resistors), while the new link is “cut tape“, which is actually my preferred resistor delivery format. It’s tidier than loose bulk resistors.

Most people use the literal parts of a BOM as suggestions. As you move along, you’ll get a favorite resistor type, film cap tap, electrolytic, etc. You’ll mix and match. As long as you have the right value, tolerance, AND the lead spacing fits in the footprint, you will be good.

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Re: Question about substituting components

Post by Whelm » Wed May 06, 2020 11:15 pm

So I'm no expert, but here's some knowledge I've picked up being a couple steps ahead of you on this escalator. Apologies for all upcoming inaccuracies me not engineer.

Different types of components have different salient properties, and it seems like many components have properties that are not relevant to SDIY stuff. So the trick is to learn what you need to know about each type of component.

Resistors are the easiest. They are defined by the material, the wattage, the tolerance, and the resistance. Metal film is what seems to be used in everything, so that's easy. The wattage rating will also determine the size (for through-hole parts). The standard in SDIY is 1/4 watt, though keep your eyes open because Befaco and maybe others use 1/8th watt. Tolerance is the degree to which any unit will vary from it's designated value. There seems to be virtually no price difference so you may as well go for 1%.

Capacitors are trickier. There are many different types of capacitor, some are polarized, some are not. There are different materials (film, ceramic, electrolytic, etc). Most capacitors you run into will be ceramic or electrolytic. However it's further complicated by the fact that there are a number of different dialectric variations on ceramic capacitors. So that's when you'll see something specified as NG0 or X7R or whatever.

With capacitors, you need to be careful with the voltage rating. I've fucked this up a number of times. The higher the voltage rating, the bigger the cap, and you need it to be rated higher than the maximum voltage it will be exposed to. In Euro this seems to generally be 25v. You can use bigger ones if you can make them fit. So if searching on Mouser for capacitors I typically filter by 25v, Radial termination, then see what I can find in the type and capacitance I'm looking for.

For ICs, transistors, regulators, etc, the main thing is the package type - SOIC, DIP, etc. There will often be many different variations on a part, like a TL072, that are functionally identical but have different naming codes for whatever reason. The same type of part (78L05, for instance) can come in very different form factors. When substituting different types of transistors etc, make sure you check the datasheet against what's on the BOM for the pinout.

You'll pick stuff up as you go and as you fuck up Mouser orders. Hope that helps somewhat.

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Re: Question about substituting components

Post by Junk » Thu May 07, 2020 3:23 am

Thanks guys there's a lot of really useful information in these answers!

I have another question, I think it's pretty basic so I'm not gonna start a new thread but just ask it here.

When I'm ordering from Mouser, it obviously makes sense to buy a bit extra of some components. Which kinds of components should I be looking at doing that with. I'm guessing any resistor or capacitor, but is there anything else? Are there specific resistors or capacitors which come up more than others?

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Re: Question about substituting components

Post by ronnieb » Thu May 07, 2020 3:50 am

Junk wrote:
Thu May 07, 2020 3:23 am
Thanks guys there's a lot of really useful information in these answers!

I have another question, I think it's pretty basic so I'm not gonna start a new thread but just ask it here.

When I'm ordering from Mouser, it obviously makes sense to buy a bit extra of some components. Which kinds of components should I be looking at doing that with. I'm guessing any resistor or capacitor, but is there anything else? Are there specific resistors or capacitors which come up more than others?
Matthew from North Coast Synthesis has some really good posts on this topic, you should definitely check them out:

Common parts to keep in stock
The vanity of "Having A Lot Of Parts"

Would really recommend picking up a kit or two from them or at very least, read the build docs.
So detailed, so informative and easy to digest.

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Junk
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Re: Question about substituting components

Post by Junk » Thu May 07, 2020 4:13 am

Awesome, thanks ronnieb!

Also what about 3.5mm jacks...

BOM is telling me to buy Thonkiconn... but I want to save money by not ordering from a bunch of different sites. A quick search in Tayda brings up a bunch of jack inputs but only one of them looks like it has the same mounting (two 'legs' coming out of the back, and one coming out the bottom and heading to the back)

https://www.taydaelectronics.com/pj-300 ... -jack.html

Thonkiconn is rated 0.5A and 30VDC
This Tayda jack is 1A and 12VDC

If amps rating is higher all should be good... Volt rating is lower, but also the input to the jack would never go over 12VDC is euro, right? Or am i missing something.

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Re: Question about substituting components

Post by Agawell » Thu May 07, 2020 4:50 am

100r 1K 10K 100K resistors
100nF (0.1uF) ceramic caps
10uF 22uF 47uF electrolytic caps - get the short ones - they work anywhere

a good idea is to get a lot of BOMS together that you want to build and buy for all of them at once - or at least look at any common components - and get them

always check price at 100 units - there's usually a significant price drop - often 100 is cheaper or only slightly more than 40 for example

make sure you know where your free shipping point is and make sure you hit it - mouser shipping is expensive
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Re: Question about substituting components

Post by EATyourGUITAR » Thu May 07, 2020 6:25 am

I order $200 from mouser, the shipping is still $8. that is cheap shipping. I order PCB from china $200 order, $48 shipping. yeah.
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Re: Question about substituting components

Post by Junk » Thu May 07, 2020 6:29 am

Found the answer to my question about the jacks here:

viewtopic.php?f=17&t=220910&p=3107831&h ... k#p3107831

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Re: Question about substituting components

Post by Studioalethea » Thu May 07, 2020 12:11 pm

Junk wrote:
Thu May 07, 2020 3:23 am
Thanks guys there's a lot of really useful information in these answers!

I have another question, I think it's pretty basic so I'm not gonna start a new thread but just ask it here.

When I'm ordering from Mouser, it obviously makes sense to buy a bit extra of some components. Which kinds of components should I be looking at doing that with. I'm guessing any resistor or capacitor, but is there anything else? Are there specific resistors or capacitors which come up more than others?
Order extra of everything always. I make sure to have at least double whatever the BOM says because I usually breadboard a circuit and leave that intact while I solder up the PCB to check voltages and such. Plus you want even more extra ICs and transistors because those are easy to damage.

Always look at the bulk price discount. Many items get a nice break at 10, so I always order at least 10 of most capacitors. Whereas you'll see things like switches, the break isn't so amazing, so a lot of times I'll decide what I need and buy those per project.

It's nice to slowly build up your 'pantry' of components, so you can experiment and learn. It gets expensive, though, so just do what you can. Have extras on hand and have fun.

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Re: Question about substituting components

Post by Studioalethea » Thu May 07, 2020 12:16 pm

Whelm wrote:
Wed May 06, 2020 11:15 pm
Resistors are the easiest. They are defined by the material, the wattage, the tolerance, and the resistance. Metal film is what seems to be used in everything, so that's easy. The wattage rating will also determine the size (for through-hole parts). The standard in SDIY is 1/4 watt, though keep your eyes open because Befaco and maybe others use 1/8th watt. Tolerance is the degree to which any unit will vary from it's designated value. There seems to be virtually no price difference so you may as well go for 1%.
If you're breadboarding, make sure the lead diameter is .6mm -- thin, cheap resistor leads are so frustrating in a prototyping environment. I buy Yageo with the MFR-25FTE52 part number prefix, and the specific value is at the end: 603-MFR-25FTE52-360R, for example is a 360 ohm resistor. I also always buy in an ammo pack, whose paper packaging I write the value on multiple times. Loose resistors are obnoxious to keep track of and remember their values.

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Re: Question about substituting components

Post by Whelm » Thu May 07, 2020 12:37 pm

EATyourGUITAR wrote:
Thu May 07, 2020 6:25 am
I order $200 from mouser, the shipping is still $8. that is cheap shipping. I order PCB from china $200 order, $48 shipping. yeah.
For me Mouser is $20 shipping no matter what, unless you spend >$99, in which case it is free. I'm surprised they don't offer free shipping over $100 in the U.S if they do for Canada.

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Re: Question about substituting components

Post by BartBral » Thu May 07, 2020 12:59 pm

Whelm wrote:
Thu May 07, 2020 12:37 pm
EATyourGUITAR wrote:
Thu May 07, 2020 6:25 am
I order $200 from mouser, the shipping is still $8. that is cheap shipping. I order PCB from china $200 order, $48 shipping. yeah.
For me Mouser is $20 shipping no matter what, unless you spend >$99, in which case it is free. I'm surprised they don't offer free shipping over $100 in the U.S if they do for Canada.
Yes, what is that all aboot...
When I order from Ze Netherlands... I get free shipping over €50,- And then they ship it all the way here... and backorders are flown over here for the same price.
Sometimes even two 'okking parts per 20x30x10cm cartboard box??? Even if I have checked the "Send when everything is available in one go" option.

Just ckecked Mouser's site... And the say:
Free Shipping
You can now enjoy free shipping whenever your order is over 50€ EUR or $60 USD. **
and then:
** May not apply to all shipping options or carriers. See details in checkout.
So best to check the options before hitting that "BUY" button.

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Re: Question about substituting components

Post by EATyourGUITAR » Thu May 07, 2020 2:54 pm

It was 2 day shipping for $8.99. just got a mouser in the mail today. Much better than Amazon.
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Re: Question about substituting components

Post by KSS » Fri May 08, 2020 5:30 am

Junk wrote:
Thu May 07, 2020 6:29 am
Found the answer to my question about the jacks here:
viewtopic.php?f=17&t=220910&p=3107831&h ... k#p3107831
Hopefully your answer was *not* to use the Tayda jacks.

Jacks and switches are the two most used and important parts of your synth. They are *not* the place to try to say a few cents. Or dollars.

Even metal which looks the same may not be the same. Phosphor bronze and beryllium copper are very different, but you won't see that when they're plated.

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Re: Question about substituting components

Post by BartBral » Fri May 08, 2020 6:42 am

KSS wrote:
Fri May 08, 2020 5:30 am
Junk wrote:
Thu May 07, 2020 6:29 am
Found the answer to my question about the jacks here:
viewtopic.php?f=17&t=220910&p=3107831&h ... k#p3107831
Hopefully your answer was *not* to use the Tayda jacks.

Jacks and switches are the two most used and important parts of your synth. They are *not* the place to try to say a few cents. Or dollars.

Even metal which looks the same may not be the same. Phosphor bronze and beryllium copper are very different, but you won't see that when they're plated.
I had that with jacks where I wanted to bend the "leads" and they just broke off of the Tayda jacks (not the fake Thonkies though)... I can imaging that this metal-fatigue would show up after inserting a jack for 100 times as well...
Since then I only use those fake Thonkies and other jack-inputs only on my breadboard or other cheapycheapy things... I hope things I made before that knowledge don't break down soon... but they probably will one day... during a liveset. ;)

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Re: Question about substituting components

Post by tonefloat » Wed May 27, 2020 4:12 pm

Hi folks! I am embarking on my first real builds (some hex Mutant Drums I bought years ago!) and have sourced most of the parts, with quite a few on back order and a few substitute parts. I have a Q about resistors that I cant find an answer to here (apologies if missed)...

I was waiting for some back order 1/4W 1K ohm 1% that were on a long lead (along with a couple other values..) so rather impatiently I just ordered some subs from eBay which arrived super fast and I thought were good to go. I then received an update from Mouser that my 1k's were in back in stock and had them shipped through.

The Mouser ordered resistors arrived today When I opened and compared to the eBay sourced resistors I noticed they were significantly smaller - around 3mm long compared to 6mm (eBay). I will go ahead and use the ones from Mouser as they from the Hex BOM - but I wondered if someone could explain the difference and significance of using 3mm or 6mm? I have subbed some other resistors so wondering if it will be an issue using a physically bigger or smaller resistor?

I read something to do with the power & voltage capabilities; but wondering how relevant?

Multi-thanks in advance if anyone is able to advise.

Hope you are safe and well.

https://www.ebay.co.uk/itm/50-x-1-4W-0- ... 2749.l2649
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Re: Question about substituting components

Post by emmaker » Wed May 27, 2020 4:22 pm

tonefloat wrote:
Wed May 27, 2020 4:12 pm
The Mouser ordered resistors arrived today When I opened and compared to the eBay sourced resistors I noticed they were significantly smaller - around 3mm long compared to 6mm (eBay).
Typically the size and wattage are related. Higher the wattage the bigger resistor.

6-7mm sounds about right for a typically 1/4W resistor (pads are typically 0.3" apart). 3mm sounds like 1/8W or less.

Look at the Mouser data sheet for the part and validate it is the correct one before you use them.

Jay S.

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Re: Question about substituting components

Post by KSS » Wed May 27, 2020 4:44 pm

Mis-labeled 1/8W. Or mis-binned at mouser distribution. But those are 1/8W.
Except for low values, they'll probably be fine. Use ohms law.

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Re: Question about substituting components

Post by tonefloat » Wed May 27, 2020 4:48 pm


Typically the size and wattage are related. Higher the wattage the bigger resistor.

6-7mm sounds about right for a typically 1/4W resistor (pads are typically 0.3" apart). 3mm sounds like 1/8W or less.

Look at the Mouser data sheet for the part and validate it is the correct one before you use them.

Jay S.
Hi Jay, many thanks for replying - its much appreciated.

The mouser carts I followed via modular addict just specify 1/4W 1k, the resistors in the BOM cart linked are the KOA Speers, 'MFS1/4' - link here;

https://www.mouser.co.uk/ProductDetail/ ... DCT52R1001

Checking the data sheet as you wisely suggested, shows that the BOM cart linked 'MFS1/4' resistors have a physical length of 3.2mm - so that checks out. The 'MF1/4' resistors listed on the data sheet are 6.3mm and that would correspond to the eBay sourced resistors' physical length. Completely without experience I thought the bigger ones 'looked right'.

Laying both the smaller (Mouser BOM cart) and the larger (eBay) resistors dry against a 1K designation on the PCB -I'd say the 6.3mm ones from eBay look like they are mean to be! But doubt has set in due to the BOM cart - which I know has a few missing bits and anomalies - maybe also things (links) have changed over time too - admittedly Ive left it a long time to do this - and for that reason I am erring on the side of caution.

:confused:
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