My First Build - Noob Advice Required about components.

[mth5044]

4.7u = 4u7. Same goes for nano farads, so 4.7n = 4n7. It's a lot more common in resistance values, such as 4.7k = 4k7. I believe this is done because decimal points tend to vanish when photocopies and pictures were made of schematics. Dots can be hard to see. With a letter shoved in there it's much harder to mistake 4k7 for 47k than 4.7k.

For the caps - that is some times a problem, but most of the time not. Your layout isn't using anything that gets too hot if populated properly. You don't want a cap or a resistor touching power regulators or other items that are geneally heat synced. Two caps touching each other is not a problem. I'm going to assume you are using the greenie caps. You will be much better off getting the box type caps as they are way smaller and have more standard shapes. But for now, as long as they fit, your likey okay that they are touching.

Make sure that bending them doesn't cause any fracturing of the legs near the body though.

[steveyraff]

Whats confusing me is that for example, I have a cap that is tagged and labelled as 100n. But if I take a magnifying glass to it, it has 10n F printed onto the cap itself. I used conversion calculators etc online and none of them say that these are the same values? I might be doing something wrong?

[Hemmel]

Best thing you could get is a MultiMeter with a capacitor setting. I bought one (~ 30$) and I did notice that sometimes parts are mis-labeled. Especially with the ceramics, where 10pF were marked as 1pF, for example.
Unfortunately, my MultiMeter only goes up to 20µF, but then anything above that value is easy enough to read directly on the cap.

[steveyraff]

I have a few untagged Caps that I am trying to make sure I have correctly identified.

I'm still not the best at reading the various values as they seem to decimal them slightly differently on differently manufactured varieties.

Here's 3 that I am not 100% sure about. If someone could tell me what value they are. Some or all of these is hopefully a 220n cap. Although maybe some of these are 22uf ?!

Thanks again. Sorry for all the questions - the answers are helping me learn fast!

Cap 1:
Cap 2:
Cap 2 again:

Just bumping this up again as its on the previous page now and I haven't managed to work it out for myself yet. Thanks.

P.S Heres the cap with 100n wrote on it in Marker Pen. But as you can see from the actual cap printing, it seems to say 10n F.

[Jdansti]

In general:

A) If the number has a decimal, it is usually in uF. This is the case of the orange ones you have.  The orange electrolytic is 10.77uF (I've never seen one like that).   The orange poly is 0.22uF, or 220nF.

EDIT: Your orange electrolytic might be 220uF/16V.  Checking now...

Found it: It is 220uF/16V  here's the datasheet: http://pdf.datasheetarchive.com/indexerfiles/Scans-008/Scans-00160485.pdf

B) Three digits on ceramic or polys: the third digit is a multiplier of 10 (0 = x1) and the units are pF.

470 = 47 * 1 = 47pF
471 = 47x10 = 470pF = 0.47nF
472 = 47*100 = 4,700pF = 4.7nF
473 = 47*1,000 = 47,000pF = 47nF
474 = 47* 10,000 = 470,000pF = 470nF
475 = 47*100,000 = 4,700,000pF = 4,700nF = 4.7uF (This would normally be a polarized tantalum)
105 = 10*100,000 = 1,000,000pF = 1,000nF = 1uF (This would normally be a non-polar poly or a tantalum)

C) Sometime the unit is placed where the decimal place would go:

4n7 = 4.7nF
4u7 = 4.7uF

Your blue poly is 10nF.

D) Other letters and numbers pertain to tolerances, voltages, max operating temp, etc.  In general, 99.9% of the poly and ceramic caps are fine for stompbox voltages.  Watch your electrolytics though.  Use at least 16V electrolytic caps for pedals using up to 12V.  Go higher as appropriate if your pedal runs at a higher voltage.

Best thing you could get is a MultiMeter with a capacitor setting. I bought one (~ 30$) and I did notice that sometimes parts are mis-labeled. Especially with the ceramics, where 10pF were marked as 1pF, for example.
Unfortunately, my MultiMeter only goes up to 20µF, but then anything above that value is easy enough to read directly on the cap.

+1  Or get one of these:
http://www.amazon.com/Capacitance-Meter-DIY-KIT/dp/B00C5TRI3Q

A lot of us on the forum have this one.  If you build it, get some help from the forum.  I found that there's a diode labeled backwards on the instructions when I built mine.

As far as damaging the caps with heat, they normally stand up well as long as you have a good soldering technique.  This is a good video on soldering.

[steveyraff]

In general:

A) If the number has a decimal, it is usually in uF. This is the case of the orange ones you have.  The orange electrolytic is 10.77uF (I've never seen one like that).   The orange poly is 0.22uF, or 220nF.

EDIT: Your orange electrolytic might be 220uF/16V.  Checking now...

Found it: It is 220uF/16V  here's the datasheet: http://pdf.datasheetarchive.com/indexerfiles/Scans-008/Scans-00160485.pdf

B) Three digits on ceramic or polys: the third digit is a multiplier of 10 (0 = x1) and the units are pF.

470 = 47 * 1 = 47pF
471 = 47x10 = 470pF = 0.47nF
472 = 47*100 = 4,700pF = 4.7nF
473 = 47*1,000 = 47,000pF - 47nF
474 = 47* 10,000 = 470,000pF = 470nF
475 = 47*100,000 = 4,700,000pF = 4,700nF = 4.7uF (This would normally be a polarized tantalum)
105 = 10*100,000 = 1,000,000pF = 1,000nF = 1uF (This would normally be a non-polar poly or a tantalum)

C) Sometime the unit is placed where the decimal place would go:

4n7 = 4.7nF
4u7 = 4.7uF

Your blue poly is 10nF.

D) Other letters and numbers pertain to tolerances, voltages, max operating temp, etc.  In general, 99.9% of the poly and ceramic caps are fine for stompbox voltages.  Watch your electrolytics though.  Use at least 16V electrolytic caps for pedals using up to 12V.  Go higher as appropriate if your pedal runs at a higher voltage.

Best thing you could get is a MultiMeter with a capacitor setting. I bought one (~ 30$) and I did notice that sometimes parts are mis-labeled. Especially with the ceramics, where 10pF were marked as 1pF, for example.
Unfortunately, my MultiMeter only goes up to 20µF, but then anything above that value is easy enough to read directly on the cap.

+1  Or get one of these:
http://www.amazon.com/Capacitance-Meter-DIY-KIT/dp/B00C5TRI3Q

A lot of us on the forum have this one.  If you build it, get some help from the forum.  I found that there's a diode labeled backwards on the instructions when I built mine.

As far as damaging the caps with heat, they normally stand up well as long as you have a good soldering technique.  This is a good video on soldering.

Extremely helpful as always. Lots of very useful info here.

I have a multimeter, I think its just a little too basic on functions.

Thanks - helping me each step of the way here

[steveyraff]

When I was doing all my resistors I had to miss out R39 as it said it was a 50K resistor. I can't seem to find a 50k resistor on any of the component website stores I buy from, even the ones specifically aimed at those building stomp boxes etc. Is a 50K resistor rare or something?

Maybe its an error on my build guide and its supposed to be some different kind of resistor in there?

Incase any of you want to see what I am talking about, here is the build guide I am using with schematic and parts lists:
http://www.madbeanpedals.com/projects/Darkside/docs/Darkside_ver.2.pdf

I'm doing the older PCB version on the very last page.

Thanks for checking this for me Appreciate it. I am a million questions a day at this stage! 

[Jdansti]

50k is not a common resistor. You usually see 47k and 51k. Given that R39 is on the output, one option would be to use a 47k or 51k resistor. You shouldn't notice much difference. Maybe a slight decrease on bume in volume with the 47k vs the 51k.

Another option is to use either 2 100k resistors in parallel or a 47k and a 3k (3.X) in series to get close to 50k. If it were me, I'd use 47k if I had one. If all you have is 51k, go for it.

[steveyraff]

50k is not a common resistor. You usually see 47k and 51k. Given that R39 is on the output, one option would be to use a 47k or 51k resistor. You shouldn't notice much difference. Maybe a slight decrease on bume with the 47k vs the 51k.

Another option is to use either 2 100k resistors in parallel or a 47k and a 3k (3.X) in series to get close to 50k. If it were me, I'd use 47k if I had one. If all you have is 51k, go for it.

Thanks for confirming that for me. From what I had read, I figured it should be 'safe' for me to solder in a 51K that I happen to have here - but on this steep learning curve I tend to feel I need to be babysat through ever baby step incase I am doing something wrong in ignorance.

I must say - you are all very patient with the shear landslide of queries I am coming in with! Great, fast learning process this way though.

Highly appreciated, thanks!

[mth5044]

If your resistors are 5% tolerance, there's a decent chance that the 51k would be 50k anyway. Hell it could even be close to 47k 

[PRR]

Long ago, a 10K 20K 50K 100K sequence WAS common.

However that leaves large gaps of in-between values you can't buy.

Today we use a 10K 15K 22K 33K 47K 68K 82K 100K sequence, so there is no more than 10% gap between nominal values.

R39 seems very odd. There's no real need for it. There's certainly no reason for 50K exactly. I'd leave it out. But you may as well use the 47K or 51K in hand.

In general, "all" audio amplifier components can be +/-10% from the design value. We used to build everything with +/-20% parts. Today you can't buy anything worse than +/-5%. However when you can't find the "right" value on your bench, use anything within 10%.

[steveyraff]

Long ago, a 10K 20K 50K 100K sequence WAS common.

However that leaves large gaps of in-between values you can't buy.

Today we use a 10K 15K 22K 33K 47K 68K 82K 100K sequence, so there is no more than 10% gap between nominal values.

R39 seems very odd. There's no real need for it. There's certainly no reason for 50K exactly. I'd leave it out. But you may as well use the 47K or 51K in hand.

In general, "all" audio amplifier components can be +/-10% from the design value. We used to build everything with +/-20% parts. Today you can't buy anything worse than +/-5%. However when you can't find the "right" value on your bench, use anything within 10%.

Useful tip, got a better idea of the logic behind it now. I just wasn't sure how much give or take was in allowance before there was noticeable audial change.

[duck_arse]

it's nice to see a design specify bc549 transistors. they were the industry standard for low noise small signal back when we had manufacturing here in australia, and about all we could get as hobbyists for a long time.

and all the rest of the world transistors are backwards, with regard to the pinout. so, what transistors do you have in front of you, before you solder them in?

[steveyraff]

it's nice to see a design specify bc549 transistors. they were the industry standard for low noise small signal back when we had manufacturing here in australia, and about all we could get as hobbyists for a long time.

and all the rest of the world transistors are backwards, with regard to the pinout. so, what transistors do you have in front of you, before you solder them in?

To be honest - I went a bit component mad any time I've ordered. I've been enjoying the build process so much that even before completing it or knowing if it will work or not, I'm dying to start new builds! So I am stocking up.

As for transistor, I've some BC547B's, BC547 and I've just the one BC549. I've a crapload of different diodes.

[duck_arse]

all the bc5xx transistors have the same pinout, so you're ok there. it's always best to order 5 or 10 when you only need 1, and 100 when you need 10, cause then you have it later, and need to do less and less ordering. whithin your budget constraints, of course.

have you run the trasistors through the dmm transistor tester yet?

[steveyraff]

all the bc5xx transistors have the same pinout, so you're ok there. it's always best to order 5 or 10 when you only need 1, and 100 when you need 10, cause then you have it later, and need to do less and less ordering. whithin your budget constraints, of course.

have you run the trasistors through the dmm transistor tester yet?

Not yet no. But the transistors were one of the few components I didn't buy. I got them from a relative who works with electronics and he said he had tested them for me. I will be testing them myself again to make sure though. I have a multimeter here, but I have yet to learn to use it - its on my to-do list!

By the way - another thing I've been thinking about. If anyone knows any good drilling templates for 1590B enclosures I'd love to see them. I found a few online but the scale never seems quite right. I need it for designing graphics in GIMP.

EDIT: All good - made my own drilling / graphic template.

[steveyraff]

Pots Question: So I have to get some more pots for my pedal. It requires
SUS 47kA
TONE 25kB
VOL 10kA

The website I am using lists them only in the value of (K) so I am not quite sure how to work that out yet. Is 47kA and 10kA the same as 47K and 10K, if so what would that make 25kB ?  Whats the difference between Log and Linear?

Another questions is that I bought sockets for my transistors but now that I took them home I see that the holes for inserting the plugs into my PCB are in a straight line, but the pins of the sockets are offset in a triangular formation. Why is this? I guess I need to use some of my straight socket strips.

Finally, Question 3: When you guys are placing your PCB into your enclosure, what is the method generally used for securing the PCB in a stable place within the enclosure so that it is not free to rattle around? Its just something that came into my head today.

I think after this I am going to be near completion of my first pedal's circuit.

Thanks for all the help,
Steve.

[Jdansti]

All good questions.

1) The "A" and "B" designate whether the pot's sweep follows a logarithm or linear taper. A = log and B = linear. The resistance changes in equal amounts per degree of movement on a linear pot. The resistance changes according to a log function on a log pot. Log pots are normally used for volume due to the way our ear perceives the loudness of sound (this is a very sketchy explanation, so you can do an internet search if you want to learn more).

2) The triangular pin configuration used to be more common on transistors, but now days a straight configuration is more common.



You just cut to fit.

3) Some people glue or screw standoffs to the enclosure and screw the PCB to them:



Others use double sided sticky foam tape. There are other ways to do it.

[steveyraff]

All good questions.

1) The "A" and "B" designate whether the pot's sweep follows a logarithm or linear taper. A = log and B = linear. The resistance changes in equal amounts per degree of movement on a linear pot. The resistance changes according to a log function on a log pot. Log pots are normally used for volume due to the way our ear perceives the loudness of sound (this is a very sketchy explanation, so you can do an internet search if you want to learn more).

2) The triangular pin configuration used to be more common on transistors, but now days a straight configuration is more common.



You just cut to fit.

3) Some people glue or screw standoffs to the enclosure and screw the PCB to them:



Others use double sided sticky foam tape. There are other ways to do it.

Brilliant! Great summary - again, thank you!

[steveyraff]

47k and 25k are proving hard to find.

Is there some give and take here? Can I use a 50k and a 20k? I am guessing a 20k may cut off some of my accessible range?