watt, volt, degrees, preset, linear, log??????? WHAT????

[madstayen]

1st I'd like to say hi to everyone, I'm new here. Much intrigued by building my own stomp. I am an extreme noob when it comes to electronics, so hopefully someone can help me sort this out. So I got the pcb lay-out for the boogey stomp box here http://www.diystompboxes.com/smfforum/index.php?topic=46426.0. Thought to myself, this doesn't look so difficult, I can do this. I wrote down all the parts on a piece of paper, went to my local electronics store, and handed them the slip, asking a quote, like I have been doing this for YEARS!! First thing the guy asks me is, what wattages are we looking at, and temperatures, and volts, and is the pots log, linear, or preset? I felt like a true arse!!!!!!! How am I supposed to know this stuff?! I work from the drawing. So, I am wondering if there is somebody out there that can give me the CORRECT data of the parts, so that I can go to another shop and try. AAAAAAAGhh!



I don't SUFFER from madness, I ENJOY every moment of it

[deadastronaut]

lol...just be honest to the guy in the shop... (what country are you in?).....please dont say you went to maplins, they are a nightmare.

1/4 watt resistors...will do you fine.

9 volts= pp3 battery/ or voltage of common pedal power supplies.

linear is a B POT

log is an A POT.

100k trim pots..

j201= n channel j fet. (3 legged transistors)

1n4001  diode. (protects against reversing polarity.. ( reversing your power and blowing stuff up... )

as a noob, the dr boogey isn't a wise choice...but not impossible, but .i would try something else first to dip your toe into...

welcome btw.

[jmwreck]

^
agree, and the boogey seems to be pretty complicated on biasing those j201, by meter or by ear.

[Govmnt_Lacky]

Another good recommendation...

Get some SHIELDED wiring. You WILL want to use shielded wire from the input and output jacks to your stomp switch at the very least. 

[madstayen]

Thanks, I live in South Africa. The guy also asked me what the degrees of the caps should be, 85 or 105 Celsius? So I thought to myself, boet, I wanna see you holding something in your tiny little hands that is a 100 degrees Celsius! lol

[madstayen]

Whooosh I got a lot to learn. What does bias mean?

[Mark Hammer]

Yep, if you're just learning to swim, always best not to jump into the deep end of the pool wearing lead-lined boots!  

For the vast majority of building projects you will run into here, you will be fine with 1/4 watt 5% resistors, and 16 volt-rated capacitors (although 25V ratings will remove all anxiety, and should not result in any appreciable difference in cost or size, as it might have 20-30 years ago).

ANY taper of the same value of pot will work, although different tapers will provide differing degrees of "dialability" for the particular function.  For example, because of the way the circuit works, most people will find that a reverse-log taper pot will spread out the various modulation speeds for tremolo, chorus, phase, flange, et al, over a larger portion of the "speed" control, where linear or log taper will tend to bunch them up too much.

Similarly, if the function of the pot has some sort of "middle" (cut/boost and blend/balance controls are textbook examples), then you will want a linear pot so that at midpoint there is as much resistance on one side as the other.

Other recommendations, I would make would be to get yourself a sampler pack of some of the 24AWG pre-bonded wire that Small Bear sells.  When folks build something for the 10th time, or have enough building experience, it's fine to use thicker wire.  When you're starting out, and pretty much winging it, you'll appreciate having wire that is sturdy enough but turns corners easily, doesn't take up too much room if you used to much and have to bunch it up between pot and circuit board inside the box, tins easily, and fits through PCB holes without fuss.  Having multiple colours is also handy for keeping track of what wires are coming from or going to somewhere.  Once you turn semi-pro, you can use single-color, solid-core, pre-cut, pre-bent wire.

Make sure you have a nice pointy tip on your soldering iron so that you only melt the solder in the place you want to.  And if you plan on doing more than one pedal, get yourself a small bottle of liquid flux.  That stuff can work miracles sometimes.

"Biasing" means adjusting one or more appropriate resistors so that a DC voltage is applied to the transistor in question.

[jmwreck]

Whooosh I got a lot to learn. What does bias mean?

I can't explain that word clearly, but for actual usage of it to the boogey, there are 5 trimpots, 4 of which should get your j201 to 4.5v reading from the meter, read it further on madbean's chunk chunk. But, also by listening to it, you can hear that while turning those trimpots, the best sound will come out if you've hit the sweet spot.

[armdnrdy]

The guy also asked me what the degrees of the caps should be, 85 or 105 Celsius?

Just ask for general purpose caps.

I have never been asked the temperature rating for a cap!
I think that this guy was just showing you how "knowledgeable" he was.
If he were that "knowledgeable", he would have asked what you're using these caps for and then made a suggestion!

[madstayen]

  maaaaaaany thanx to all you fellas. Maybe I'm just a hard headed guy, but I am determined in building the boogie. I sincerely appreciate all the help you so freely give, and I will keep you okes updated on how the build is going.....           ......and I will most likely be asking another 1 or 2 Q's on this build. Thanx a lot guys.

[madstayen]

so then I guess I can ask for linear pots, and give them the detail in the drawing (GAIN is 1M-A) etc?

[Mark Hammer]

ALL things are buildable.  It's just a matter of how long a person wants to wait before arriving at functionality.  Some people can persist at a complex task without losing steam for quite a while, where others need to have some sense of impending or actual success in order to maintain motivation.

The Dr. B is far from impossible, and I suppose you are better informed about your own motivational limits than anyone else here would be.  Just know that you may have instant success or you may be faced with a couple of months of exasperation and asking questions here.  Either way, we'll be here to support you or congratulate you...whichever comes first.  

Typically, whenever a newbie asks for recommendations for a project, I like to recommend a loop-selector.  My reasoning is simple:
- there are no components really needed other than jacks, switches, and a box,
- none of the parts is critical
- nothing requires adjustment or fine tuning,
- it's easy to build and has no real issues as far as power or layout is concerned,
- you may not like the tone of the Dr. Boogie 4 months from now, but you'll always have a use for a loop selector.

[Hemmel]

Welcome, Madstayen,

Don't worry about questions here. The community is very helpful (I've gotten great help from many here).

If you're using the PCB layout shown in reply #10 on the thread you linked to (reply made by "mydementia"), then your pots can be identified as audio (log) or linear by the "-A" or "-L" shown after the value.
For example, 1M-A is a 1 Mega-Ohm Audio (log) pot and 100K-L is a 100 Kilo-Ohm Linear pot.

Now also, depending on where you are in the world, you might or might not find the exact values (such as 22k pots, I can't find any here in Montreal. I can find 25k pots, though, which will do. Same for 220k, 250k will do).

[madstayen]

  Ah, makes sense now, thanks. I will see what I can get. Thanks guys, lotsa help, truly!!!!!!!!!!!!!!

[PRR]

> I guess I can ask for linear pots, and give them the detail in the drawing (GAIN is 1M-A) etc?

"1Meg A" is *probably* Audio taper.

Linear would work electrically, but frustrate the user because half the action is in the "0" to "1" crack of the knob.

Yes, bring the plans, IF you have a too-helpful shopkeeper.

105 degree C caps are used in high power amps, especially tube amps. They may never hit a hundred, but the life at 105 deg C and full energy rating is only a month or few. Working cooler, they last longer.

As you say, DIY stage-toys don't need high-temperature caps. You will faint before the caps do, the total load-hours is really quite small, and if after many years the caps do fail you can fix it yerself.

Yes, in stompbox work the "Watts" are usually irrelevant. Many positions could be filled with 0.001 Watt resistors. But they don't make them that small, if they did you couldn't find them on your bench, and they'd cost more than "regular size" resistors. "Regular size" used to be 1/2W, lately 1/4W. Often 1/8W parts are fine. Anything smaller is rare and expensive.

-------

BIAS: transistors only pull one way. Like a mule that pulls only to the left. Audio swings both ways (Guitar string swings up AND down, speaker cone moves in AND out). To make a one-way device work both ways, we "bias" it to a half-way condition, so that the audio can swing both ways from there. Like tieing the mule to a spring to a tree on the right, now the reins can swing the mule left or right.

For an "ideal" (clean) amplifier we bias to half-way. For distortion effects we sometimes bias "bad", because that is a more interesting sound.

Another thing. Most "good" circuits tend to be self-biasing. (You don't bias your cellphone or TV.) Many guitar distortion effects originate in olden times when self-biasing cost too much; or have been re-invented by people without complete understanding (or who love to tinker). Also distortion is a "bad" amplifier and different users will have different notions of "bad" and thus favor different (mis-)biasing.

[madstayen]

  so the build is going quite good so far, pcb is done, looks good, got most of the parts yesterday, except for the j201s. only got 3. rest will come tuesday, maybe wednesday. for some extremely odd reason, you dont get 5nf, or 3nf caps in south africa, but you do get 4.7nf, and 3.3 nf. will this make a big difference? can i use them like that, or do i have to change something, or import the right ones? will post pics tomorrow. thanx guys.

[gcme93]

We very often substitute parts for the most similar value we can get hold of (or have around for the lazy ones!). The best thing to do if you're not sure is add a socket in at that point, like two of these pins:

You can then easily swap in different values to see which works/sounds best. You'll find a lot of people do this in circuits that have a choice of transistor, as transistors are quite a core part that can change the sound of a pedal. Always nice to try out different variations!

To answer your question more directly, those two substitutions you've suggested should work perfectly. Try and remember which parts aren't exactly the right value so you can let others know if you need to 'debug' it.

Good luck!

[Jdansti]

4.7 nF and 3.3 nF are standard values. 5 nF and 3 nF are uncommon. 99% of the time you can use the closest standard value.  Here's a table of capacitor and resistor standard values:

http://ecee.colorado.edu/~mcclurel/resistorsandcaps.pdf

[Thecomedian]

You can also add parallel resistors for a lower resistance, or series caps for a  lower capacitance. Series R and parallel C for simple addition of values together.

1/x both values, add those together, then 1/x the result, if you are doing parallel R or series C.

I have 47u caps until my Tayda shipment arrives on the snail bus, so If I need 20-22u I just series 2 47u's (the answer is 23.5u). This also happens to be a good way to get very strict values out of high tolerance (or is it low? Which one means more % drift from desired operation) caps or resistors. Find some over and unders and put them together to get within 1% or less of the actual schematic value.. most times you probably won't need to do this.

If you do happen to find yourself in a situation where the simulations or math calculations show too much drift for falling away from the "ideal" number by 5% or more, you can either buy 1% resistors and caps (expensive), or fab your own use over/under mixes, cheaper too.

[madstayen]

  Well, turns out Kings of Chaos been so on my mind, I only realized now that i printed the pcb inverted from what it should be, face-palm, face-palm, face-palm, face-palm, !!!! Back to reprint, 

ooops, also turns out I cannot post images