# Question For The DIY/Electronics Folks



## keto (May 23, 2006)

Iyam a total noob with respect to electronics, but am teaching myself and trying to build a few pedals.

In my search for parts, the schematic for a Jordan Bosstone calls for a 50pf capacitor. Another schematic, for the Red Llama, calls for a 51pf cap. 

All I could find were 47pf 'square box' caps, they were cheap so I bought a pack of 5. Are these going to work, is that value 'close enough'?

I can find and link the schematics/layouts if it will help.


Also....I forgot to clarify at the store, too much on my mind. Is a c333kaa the same as .033uf? Is a c223kaa the same as .022uf?

Thanks in advance!


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## keeperofthegood (Apr 30, 2008)

Post up the schematics anyways but I will offer a wild guess. The lower the capacitor the higher the frequency of the circuit it is in. 50pf is pretty low, it could either be a timing element or a high frequency bleed off or blocker. In the timing case yes, a few pico farads can have a fair impact, in the bleed off odds are they will be close enough.

In another manner they can be seen as the same:
20% tolerance so 47 + or - 20% would be:

47 + (47 * .2) = 56.4
47 - (47 * .2) = 37.6

So yea, I would just go with it and not worry


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## Guest (Dec 29, 2009)

+1 to don't sweat a few microfarads. If they're on filters it's likely you won't hear the differences. And you won't screw anything up fooling around with alternate values.


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## mhammer (Nov 30, 2007)

Ditto.

It is fair of you to inquire about component values and wonder how they change the sound. They do, for sure. But the fact of the matter is that, unless otherwise stipulated, most passive components will have the sorts of tolerances/variation that make it unworthy of your worry of small differences. certainly, if you want the tone to be a little more this way or that, you can play with component values. But in most instances, if a valid schematic is wired properly with values that are close enough, it will work; maybe not to your satisfaction, but it will work well enough for you to know what it is you like about it and what you wish to change.

The Bosstone is a cool little circuit. by the way. There are two versions of it: a California and a Nashville version. I've only ever built the California version.


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## keto (May 23, 2006)

So, I finished it up....but I've never done this before, and it doesn't make fuzzz. I couldn't find switches, so I tried to wire it up without a switch and that *could* be the problem. Anyone care to take a peek and speculate?

You can see the intended layout above.


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## mhammer (Nov 30, 2007)

I notice that you have a metal can transistor. Note that their pinout is somewhat different than the usual black plastic type. Possible you don't have the right pins in the right place?

The soldering needs a bit of work. I'd recommend making ground connections not by simply bending a piece of wire over your "ground bar", but actually soldering to it. Remember that in the world of electrons, a one micron gap that is not visible to the eye is like leaping across the grand canyon.

These are all typical beginner errors. Been through all of that myself....too many times to want to think about. In time, you'll anticipate all of that and experience the joy of a build that fires up at first go.


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## dtsaudio (Apr 15, 2009)

keto said:


> Is a c333kaa the same as .033uf? Is a c223kaa the same as .022uf?



Yes, that's correct. The third number is the number of zeros to give the capacitance in picofarads.
ie. 333 = 33000 picofarads = .033 microfarads


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## greco (Jul 15, 2007)

mhammer said:


> Remember that in the world of electrons, a one micron gap that is not visible to the eye is like leaping across the Grand Canyon.


Good one ...must remember this!! :bow:

Cheers

Dave


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## keto (May 23, 2006)

Thanks folks!

-I double checked the pinout of the 2N2222A metal can trans, I have it correct.

-I had trouble getting solder to stick to my bridge wire, the bare copper one....but I do think there is a connection. I may tear it all apart and start over, got some different bare-but-tinned wire yesterday to use for this sort of thing.

I was much more suspicious of my wiring to the input jacks being incorrect, especially given I have done this without a switch.....I ended up with an extra ground wire, which I put to the 'attack pot' ground.


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## Guest (Dec 29, 2009)

Make sure you haven't accidentally shorted tip to ring on your in and out jacks. Use a MM in short mode to test that there's no path between them. Omitting the switch should actually simplify things.


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## keto (May 23, 2006)

iaresee said:


> Make sure you haven't accidentally shorted tip to ring on your in and out jacks. Use a MM in short mode to test that there's no path between them. Omitting the switch should actually simplify things.


Have a DMM, don't know how to use it properly. Ah, the joys of self-education. But if you look at the pic above, the black wires are ground wires so you should be able to see what's what on the input/output jacks. I'm 99.99% sure I got them right.

So, I've rebuilt it from scratch. I'm down to the last transistor, the metal cap 2N2222 (2222A in this case, that's actually another question - should it make a difference?)

I have myself good and confused about which way to orient it, further to Mark's post above. I thought I had it right....last night I built it

2N2222A 2N3906
e------------e
b------------b
c------------c

This makes sense to me, because both 'c's' go to ground. See below for possible flawed logic on my part.

I know the 2222 is NPN and the 3906 is PNP, but I don't understand how that relates to what I am building.

Help?


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## Guest (Dec 30, 2009)

keto said:


> Have a DMM, don't know how to use it properly. Ah, the joys of self-education. But if you look at the pic above, the black wires are ground wires so you should be able to see what's what on the input/output jacks. I'm 99.99% sure I got them right.


There should be a mode on your DMM that lets you probe for continuity. Basically it beeps at you when the path between the two probes is connected (for example: it beeps when you touch the two probe ends together creating a continuous path from one to the other). Put it in this mode. Touch one probe to the tip portion of the jack, the other to the sleeve. It shouldn't beep. If it does you have solder flowing between them on the jack. It can happen if you over-use solder on those jacks.



> So, I've rebuilt it from scratch. I'm down to the last transistor, the metal cap 2N2222 (2222A in this case, that's actually another question - should it make a difference?)
> 
> I have myself good and confused about which way to orient it, further to Mark's post above. I thought I had it right....last night I built it
> 
> ...


Are you using this schematic for your circuit: http://www.diystompboxes.com/pedals/bosstone.gif ??

It sounds like one of your transistors is in backwards. Double check that for the _NPN_ transistor its _emitter_ leg is tied to ground. And for the _PNP_ transistor its _collector_ leg is tied to ground.

This is a great pedal BTW. Stick with it! I have one Mark built and it's awesome. See?


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## keeperofthegood (Apr 30, 2008)

keto said:


> Have a DMM, don't know how to use it properly. Ah, the joys of self-education. But if you look at the pic above, the black wires are ground wires so you should be able to see what's what on the input/output jacks. I'm 99.99% sure I got them right.
> 
> So, I've rebuilt it from scratch. I'm down to the last transistor, the metal cap 2N2222 (2222A in this case, that's actually another question - should it make a difference?)
> 
> ...



 There is a much forgotten rule with transistors. Never trust them run to run. While the "standard" for company A is EBC, they could always put them into the molding machine backwards, CBE, depends on how good or bad a day the guy working the line has had. And just because NEC did it one way, is no guarantee that Vishay did it that way. So, always verify with a DMM. The Base - Emitter Junction Resistance is less than the Base - Collector.


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## keto (May 23, 2006)

Layout here: http://www.aronnelson.com/gallery/main.php/v/MarkMs-Gallery/album15/album76/Jordan_Bosstone_LAYOUT.gif.html

Well, I went ahead and guessed before you 2 posted  ((did it same way as last night, intuitively that should be right)) So....I have output, but only if I HAMMER on the strings....single notes yield 0 discernable output. It's extremely gated when it does put out....and fuzzy, sounds more or less like what I expect, but should be less gated and more output.

Is this symptomatic of anything specific?


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## keto (May 23, 2006)

Anyone? Thanks in advance.


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## keeperofthegood (Apr 30, 2008)

I would suggest removing D1 and D2 temporarily. *Edit, I say this because they short the signal out. If, for any reason, they were over heated and damaged, they could act as a very low resistance load, dropping your signal in/out. This is step 1.


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