NOOB - What parts do you keep on hand?

I'm interested in getting into this hobby more, and wondering what parts most of you keep "on hand" for various projects? I'm interested in building amplifiers mostly, but eventually other things like DACs etc. While I understand the basic process of ordering a BOM for a project, from reading lots and lots here on the forum I get the sense that people have accumulated a good "stock" of piece parts through their time in the hobby. For someone just starting out, what would you recommend? I don't want to get in to a project just to find I need some $.20 part which I have to order. Is there a set of basic values for piece parts that one should have at hand?..or is the variety of components just so vast that there's no point in even trying? Say I wanted to spend $200 to fill a parts bin with resisters, caps, screws, standoffs, hook up wires, fastons, etc, what would I order?
 
Well, it's an addictive hobby so be prepared for a few years of building. What you do is buy a few extra parts when your order them for your first build - sometimes there is a lower price if you buy 5 or 10 and for some parts that are cheap, like resistors, just buy a big stash. Then you start adding parts from junk that you find, stuff friends give you etc.

What you avoid is collecting any suspect parts in terms of possible fakes. Just not worth the savings. I bought some transistors from China-eBay once and I refuse to use them in an active circuit (they were used by cutting off the legs and using them as spacers in one of my projects).
 

adason

Member
Paid Member
2004-11-10 8:31 pm
Maryland
I keep small signal resistors, all values, in small bags stock 10-50 all the time. That way if I decide to build something, I am only ordering caps, transistors and power resistors.

Over the years I accumulated lots of useful transistors, so often I do not need to order those, and select the circuit I have transistors already. When you are going to build some transistor based amplifier, order few extra, just in case.

When it comes to caps, I have generic power supply caps, generic mp caps for crossovers, when experimenting, but there is no way to stock each value, each voltage, as things get more complicated here. Still, I have boxes and boxes, so often I just need to dig in and I often find what I need.

Do not go nuts on ordering all parts, there is a chance you will not use them.

You will accumulate stuff as you go no matter what in this hobby, no need to go overboard right away.

Good luck!
 

U230421

Disabled Account
2017-02-07 1:54 pm
On stock:
resistors, pots, trimmers, nonpol caps, electrolytes, semi's (bjt, jfet, diode, zener), wires, cables, connectors, casings, heat sinks, transformers, switches, pcb...
And tools:
obvious metering, scope, power supplies, generator, iron, pc with simulation & cad...
And documentation:
databooks, datasheets, application notes, articles, magazins, designs...
And inspiration:
set course to find the semiconducter replacement for a tube (done: n&p variations)
And:
DIY!!!
 
I have been in electronics for 65 years, professionally for about 50. I have been accumulating parts all along. I have tens of thousands of dollars wrapped up in parts. And you know what? I still have to order parts every week.

Just start ordering extra parts with each order. Look at resistors. I can but six of them for a dollar, or I can order 100 of them for a couple bucks more. if I need 220k resistors, I buy a bag of 100.

A useful MPSA06 transistor is maybe 30 cents, or a couple dollars for 10.

But no matter what you buy, there will always be something you need.
 
Look at Mouser or Digikey for kits of resistors, hardware, capacitors, etc.
I've rarely got a bargain from those guys. $.20 minimum for every resistor
Otoh, if I need a 470 ohm metal film resistor, 1/2 watt, I'll put 455 to 486 limits in newark, .5 to 3 watt. A lot of times I'll get 1% 457 ohms or something for $1.50 a hundred, whereas the spot on 470 ohm 10% resistor is $.18 each. 10% resistors are just as likely to be 100% nominal value-9.5%, the days of random distributions are over.
And be patient. I have bags of decades of resistors, I put a card in each of what values I'm missing (of 1.0, 1.2, 1.5, 2.2, 3.3, 4.7, 6.8, 7.5, 8.2, 9.1) I'll search the ones I don't need that day, if they are $.20 each they can wait. If they are $1.00 for 50, then I'll stock up on that. the freight is $9 a box, may as well fill it up.
If your work vacuum tubes or PA amps, you may need 2-3 watt resistors to hold off the higher voltage. There is a voltage rating, short resistors will arc over with dust on them.
Transistors, I keep npn & pnp in TO92 Vceo 80v, 120v, TO220 80 v & 160v 300v, and TO247 or 263 150v 250v 350v. The numbers may not match, like one time MPSA06 is $.33 ea and MPS8099 was $8 a hundred. Slight difference in Ft is all the difference, and the cheap ones were the faster ones. Look for performance in the selector tables, instead of specific part numbers.
But sometimes digikey or mouser is the only place that has what I want, I don't buy much extra there because they don't play the closeout game.
Wire check the closeouts, I had to pay list for black but nearly every other color can be had on closeout sometime.
Ebay & surplus house wire is sometimes attractive particularly in teflon & kynar, which don't melt when you touch them with a soldering iron. The worst wire was NTE solid core from a real distributor, that stuff is brittle and fractures easily.
Screw hardware is cheaper from mcmaster.com in 50's or 100's and if you order SS 318 or milspec you can avoid the ones from a country that makes "steel" out of scrap copper & lead. I buy nema CE board from them too and saw & drill them myself, perfboard at $10 a 4" x 6" square is rediculous.
 
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kodabmx

Member
Paid Member
2011-10-31 1:00 am
Toronto
I keep 1% resistor in almost all values in 1/4W and 1/2W, and I keep 1W, 2W, and 5W MO power resistors in common values for my designs (2k - 100k basically).

I also keep polypropylene caps from 0.01u to 2.2u, and common electros for tube amp power decoupling etc. I keep an assortment of LEDs and certain voltage regulators. Oh, and LOTS of tubes (Hundreds of them).

Oh, and diodes and bridges, zeners, too. Pots, heatsinks, tube sockets too.

Then there are switches, relays, power connectors etc. I have six big parts cabinets full of components.

As far as hardware, I buy it all from China. 1/10th to 1/100th of the price of buying from US or Canada. This includes M3 nuts, cap screws, stand offs, and M3 torx bolts, capacitor clamps etc.

I get my wire from Sayal. I'm sure there are more things I forget...

Cheap Chinese components are fine for all but the most demanding task, certainly good enough for prototyping an idea, and you can always "spring" for higher quality parts from Digikey or whatever.
 
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phase

Member
2004-10-04 11:59 pm
At the beginning it’s good to strip as many used appliances and audio devices for their components as possible in order to have stuff around for experimenting.
For tweaking speakers, it’s good to have a stash of 1uf polyester caps around, at least to determine values before spending on more expensive parts.
A $20 soldering iron will work at first, but be prepared to buy something better if you stay in the hobby.
 
... Is there a set of basic values for piece parts that one should have at hand?..or is the variety of components just so vast that there's no point in even trying?

Both are correct.

... Say I wanted to spend $200 to fill a parts bin with resisters, caps, screws, standoffs, hook up wires, fastons, etc, what would I order? ...

What do you want to build? Will it be with electron tubes or solid state? Parts with long leads you can solder to, or SMD / SMT parts? Or both?

You will use resistors the most. In most instances, values are not that critical, and you can use something close to what someone else used. You will get an intuition for this over time.

Start with the decades, at least 20 or 25 of each:

10, 100, 1000, 10K, 100K, 1M
22, 220, 2200, 22K, 220K
47, 470, 4700, 47, 470K
68, 680, 6800, 68K, 680K

you can fill in more values later, if need be. If you are doing solid state stuff, 1/8 watt is fine, 1/4 watt if you like bigger parts. You might want a few potentiometers, maybe 10K and 100K, a couple of each.

You will use a lot of bypass capacitors and coupling capacitors. In audio, the values are pretty large: 10 nF, 100 nF, 220 nF. Larger caps in electrolytic: 1 uF, 4.7, uF, 10uF, 100 uF would be a good start. You might want a few 1000 uF for filters in power supplies. 16 to 25 volts is ok for solid state.

You'll want some general purpose transistors; 2N2222, 2N2907, 2N3904 and 2N3906 are common and can be used as amplifiers and switches. You'll probably want some inexpensive n channel JFET's, but these part numbers come and go. A few three terminal positive regulators are handy to have around: 78L05, 78L08, and 78L12, three or four of each to start. Maybe a ten strip of a few cheap op amps like 5532 or 5534, Or even 741. Maybe a half dozen LED's. Rectifier diodes like 1N4001 or maybe a little higher PIV.

Velleman has a wire kit that has lengths of eight or ten colors, but starting out you can probably get by with red, black, and one or two more of your choice.

You obviously need a source of power, either a small variable power supply, or some battery holders to hold penlite cells. A small power supply would be a good first project; you'll need an 117 to 25 volt transformer or equivalent wall wart, LM317T IC, and a 5K potentiometer in addition to your "stock" stuff.

You need something to build on, either perforated boards or clad boards, depending on how you want to do it. I woudn't fool with screws, fasteners, other hardware, etc.. Get those as needed when your project is mature enough to put in a case or chassis.

Last but not least, you need good soldering iron or station, that can be set to and hold a temperature, plus solder. I've gotten to where I like the solder with a small bit of silver in it. If you will be doing SMD/SMT a hot air gun is just about essential for reworking things.

If you don't have an oscilloscope, you will at least want a VOM / DMM that can reliably read audio frequency ac voltages in the millivolt range.

You can get "assortments" of general purpose common parts, both leaded and SMD/SMT, from China really cheap via ebay or AliExpress. I have had good results with these for hobby use.

My $0.02 USD, good luck, hope it was helpful.
 
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I do agree with just getting a few extra parts with every order and in addition I like to buy stock from people who are not in this hobby anymore or from house clearances. Except maybe for caps there is a very good chance those parts still work and also a very good chance they are genuine. Also no matter if you are new to this hobby or if you are doing it for years I still think its fun to go through piles of parts discovering some rare things like transistors which go for several € each on ebay or some of those green wirewound resistors from back in the day which are praised to be the best by some people and I got a kilogramm of them for 1€
 

H713

Member
2017-11-24 11:21 pm
Madison WI
Figure out where the price break is when you order parts- sometimes ordering 100 is almost the same price as ordering 25. Everyone mentions resistors and film/ceramic caps. Make sure you have a metric busload of 100nF 100V "box" caps. You'll use a lot of these if you build solid-state projects.

Here's a few semiconductors and other things that I personally like using:

1N4007- 1 kV 1A diode
1N4148 100V small signal diode- commonly used for protection, biasing, etc

BC550C and BC560C. IIRC, the C version has a higher current gain. Reasonable low-noise general purpose transistors.

KSC1845 and KSA992. These are a 120V part IIRC, relatively high current gain and low noise. Good for projects with higher voltage rails.

BD139 and BD140. About the cheapest TO-126 package. Good for drivers and VAS. Output transistors for preamps.

KSC3503 and KSA1381. Excellent driver / VAS transistors. 300V rated, but more expensive than BD139s.

IRF510 - Good generic MOSFET for general purpose switching.


Op-amps: Everyone has their personal favorites. You don't need to stock 20 different types, but here are a few to consider:

NE5532- Good general-purpose audio op-amp.

LM4562- Better than a 5532 for most things, but a bit more costly and with a higher input bias current. Pick your poison.

TL072/TL074- World's most common JFET input op-amps, and they don't sound half bad if used correctly.

OPA604- Lots of people rave about how this thing "sounds". I love the fact that it works with up to +/- 24V power rails.


Power transistors are expensive, so typically I suggest buying these as-needed. Get a few extras whenever you buy them so you have a few in your parts stash. With that said, get some TO-3 package 2N3055s and 2N2955s to keep on hand- lots of equipment uses these as series pass transistors, so it's good to have a few on hand for servicing linear power supplies.

IXCP10M45S HV current sources- only if you play with tubes. These make great current sinks for long-tail pairs.

LM317 / LM337 adjustable regulators. You should have some 78xx and 79xx regulators on hand too, but I prefer to use the 317 and 337 in my own designs because I can set the power supply rails at exactly +/- 18V or whatever. They are also lower noise than fixed regulators.

Zeners- Get some common values from 3.2 to 30 volts or so. If you play with tubes, you will want some HV zeners too.

Everyone tells you to get a variac and isolation transformer, but I suggest keeping at least one big control transformer with a pair of 120 windings and a pair of 240 windings. This is useful for working on 120V equipment (if you're in Europe) or 240V equipment (if you're in the US). It can also make a seriously wicked plate transformer if you're into tubes.