My First Build - Noob Advice Required about components.

[duck_arse]

apply the 10% rule. any value can usually be replaced by another value, if it is within 10% of the original specified. plus or minus.

(any system that can't survive a 10% change is not stable. I think that's right, but I'll bracket it in case.)

and I realise 25k is not 110% of 20k, but still.

[deadastronaut]

in the UK .. (sorry no idea where you are)

we generally have 47K and 22K pots

in the USA they generally have 50K and 25k pots

because they are just awkward, ..

i doubt its going to make it very noticable/unusable if its not bang on spec.. there are 'tolerances as DA said with components anyway' ..

[steveyraff]

I'm in the UK. Well, Northern Ireland depending on what your political stance is. Mine is F* Politics lol.

I was just going to go ahead and put 50k and 20k in there, but I was worried it would cut off the range of those pedal functions?

[Jdansti]

While you're at it, you might want to experiment with a 50k for the tone. You'll eventually use the spare pot in another project. The reason I say this is that most other Muffs use 100k. I'm not sure why Cornish used 25K. It might have something to do with the caps and frequency cut offs. That's beyond my understanding. I'm just saying that while the 20k will probably be fine, it wouldn't hurt to clip a 50k in there too and see if you can hear the difference.

[steveyraff]

While you're at it, you might want to experiment with a 50k for the tone. You'll eventually use the spare pot in another project. The reason I say this is that most other Muffs use 100k. I'm not sure why Cornish used 25K. It might have something to do with the caps and frequency cut offs. That's beyond my understanding. I'm just saying that while the 20k will probably be fine, it wouldn't hurt to clip a 50k in there too and see if you can hear the difference.

Good idea - I'll experiment and see what the difference is. Cheers dude.

[deadastronaut]

yeah @#$% all that political crap!.. make some noise!.

[steveyraff]

Ok - Resistors and Caps all done!

Today is Transistors then Diodes.

1: Heres my first question today... the guide states Transistors 1 to 6 to all be BC549. I have all the sockets in for these, but I do NOT have 6 BC549's. I only have one of those. Then I have two BC547B and three BC547's.

Its still 6 transistors in total. I just don't know how major the sound difference is going to be. These will still work on in the circuit though, right?

2: Also, my 5th Diode is only for polarity protection (or so I've read). It asks for a 1N5401. On most other builds I see a 1N4001. I dont have a 1N5401 but I do have lots of 1N4001, and a very large, beastly looking 1N5822. Is it ok to just use a 1N4001 here? I guess I am just using 9v batteries for now and maybe later a standard UK boss style mains power supply.

3: I have a the 3PDT switch wiring diagram here. The only problem is, the connection terminals on the back of the switch doesn't seem to have any markings whatsoever. This means I am unable to tell if there is a specific way around to start wiring it up. Can someone please explain this to me?

Many thanks.

Steve.

[steveyraff]

Any takers?

[GoranP]

Im on my phone so I cant type much but to address your third question, you dont need any markings. Almost all (if not actually all) 3pdt wiring schemes will have you orient the switch that the solderlugs are oriented horizontally. Now you have three vertical sets of three dual throw switches, hence 3pdt. These are completely interchangeable and as long as you keep "columns" separated, its all the same and you can have many diagrams actually showing the exact same thing while looking completely different. Which schematic are you looking to use?

[steveyraff]

Im on my phone so I cant type much but to address your third question, you dont need any markings. Almost all (if not actually all) 3pdt wiring schemes will have you orient the switch that the solderlugs are oriented horizontally. Now you have three vertical sets of three dual throw switches, hence 3pdt. These are completely interchangeable and as long as you keep "columns" separated, its all the same and you can have many diagrams actually showing the exact same thing while looking completely different. Which schematic are you looking to use?

Thanks - at the moment I am using Madbean's version that came with the guide for this particular circuit. You can find the wiring guide I am using HERE:  http://www.madbeanpedals.com/projects/Darkside/docs/Darkside_ver.2.pdf

[steveyraff]

I'm also confused as to why all my DC jacks have only 2 lugs - the wiring diagram I have required it to have 3 by the looks of it. 

[GoranP]

Again, I cant type much so check this out and see if it helps

http://www.beavisaudio.com/techpages/PedalPower/

[mth5044]

That is a thoroughly confusing wiring diagram especially for a new person at this. Your switch will still be held with horizontal lugs as Goran said and it will be situated correctly compared to the PDF. However, the wiring diagram is not true bypass, which you may or may not have known. You also don't even need a 3DPT, a DPDT will do, but if you don't have one, a 3PDT is ok.

Your signal will always see the input buffer as the input jack is hard wired to the input buffer (non true bypass). When the switch is in the effect off position, the input buffer connects to both the output resistor network and the input of the fx buffer. I have never seen this done this way. In the other position, the input buffer and fx buffer are still connected, but are no longer connected to the output resistor network, but the fx output is, giving you a fuzz signal. This is what is happening on the left side of your switch.

On the right side is your LED indicator when switched to ground is on.

Can you show your DC jacks? Are they the standard plastic kind?

[steveyraff]

That is a thoroughly confusing wiring diagram especially for a new person at this. Your switch will still be held with horizontal lugs as Goran said and it will be situated correctly compared to the PDF. However, the wiring diagram is not true bypass, which you may or may not have known. You also don't even need a 3DPT, a DPDT will do, but if you don't have one, a 3PDT is ok.

Your signal will always see the input buffer as the input jack is hard wired to the input buffer (non true bypass). When the switch is in the effect off position, the input buffer connects to both the output resistor network and the input of the fx buffer. I have never seen this done this way. In the other position, the input buffer and fx buffer are still connected, but are no longer connected to the output resistor network, but the fx output is, giving you a fuzz signal. This is what is happening on the left side of your switch.

On the right side is your LED indicator when switched to ground is on.

Can you show your DC jacks? Are they the standard plastic kind?

Aaah! Really? The more I work at this pedal the more I realise I picked a very ambitious one for a beginner to start with. Dammit. I would have preferred True Bypass for sure. I guess its how the original Cornish G-2 was wired. This sheds some light on things I'd read back at the start about how clean the input buffer is on the original G-2. I guess it needs to be if its gonna preserve the signal quality if it is not true by pass and always running through that part of the circuit.

Oh well.

Here is a pic of the DC jack. I've probably wired it wrongly. It had two identical lugs except one was slightly shorter than the other.

This outboard wiring is turning into the most difficult and confusing part for me!!

[Jdansti]

Your DC jack will not allow you to disconnect the battery when you plug your adapter into it. If you use that adapter, do not try to wire the battery to it unless you add an additional toggle switch to switch between battery and adapter.

Re true bypass: You can still do it. The pedal isn't a limiting factor. I'm at work right now, but I'll send send you a TBP scheme that will ground the board input during bypass.

[steveyraff]

I think I have everything wired up as in the diagram for now anyway.

The only thing missing from my circuit now is the transistors.

I have the sockets for them all in. I have a diagram showing me the pinouts too. But my schematic doesnt show me which pin goes where.  Anyone care to shed some light on this for me?

[mth5044]

I warned you in the second post it was difficult build 

For the trasistors, look at the circuitboard. There are outlines that show the orientation of the transistors. If you look at the data sheets for all your transistors, you can tell if they are the same or not (I believe this was discussed on page one as there are imagines of pinouts there). If they are all same, place them as the silk screen on the PCB shows. I don't always trust the image on the PCB, but Madbean makes very good layouts and I would imagine he took the time to get it right. In my experience it's mostly a problem when it comes to layouts made on DIYLayout program (I think that's the name anyway).

So if you see one of the transistors has an opposite pinout from the 549's on the PCB, rotate the transistor 180 degrees. You should be able to identify what the pins are with the datasheet, schematic and PCB.

[steveyraff]

Ok guys, I have EVERYTHING wired up now. Its not in its enclosure yet.

I plugged it in for its first test.

Good and bad news. I think something is wrong, but I think it is minor.

When I plug in and turn my amp on - all I hear is lots and lots of noise. Just one big buzz. But when I touch a metal surface with my hand then play the frets with my other hand - it sounds like it works pretty well. I presume this means a grounding issue? I dont think I even have done anything to ground it yet?

Also, I don't have an LED hooked up yet. If you look at the schematic I am using on the very last page of this PDF http://www.madbeanpedals.com/projects/Darkside/docs/Darkside_ver.2.pdf you can see on the left hand side, it shows where an LED goes. At the moment, I have two wires soldered in here, they are going no where though. Do I put my LED at the end of them???

If so, which way around??

Thanks.
Steve.

[steveyraff]

I warned you in the second post it was difficult build  

For the trasistors, look at the circuitboard. There are outlines that show the orientation of the transistors. If you look at the data sheets for all your transistors, you can tell if they are the same or not (I believe this was discussed on page one as there are imagines of pinouts there). If they are all same, place them as the silk screen on the PCB shows. I don't always trust the image on the PCB, but Madbean makes very good layouts and I would imagine he took the time to get it right. In my experience it's mostly a problem when it comes to layouts made on DIYLayout program (I think that's the name anyway).

So if you see one of the transistors has an opposite pinout from the 549's on the PCB, rotate the transistor 180 degrees. You should be able to identify what the pins are with the datasheet, schematic and PCB.

You were right - it IS difficult lol. Thanks for the info. If anyone can help me on the problems I've stated in my previous post - it'd be great!


I have the LED working now - but I just need to know how to ground the thing while its out of its enclosure. All I hear is very loud buzzing. But when I touch something metal with my other hand the pedal actually sounds BRILLIANT! Really freakin good! I am very excited now. I just need someone to help me with this last little step and I can rock out for the rest of the night and enjoy my hard work! lol
Almost at the finish line I think.

Steve.

[mth5044]

If you have the bypass wired as it is showed, you should have the LED wired to the LED space on the bottom right side of the PCB. Not sure what other part you are talking about.

Everything needs to be grounded to the power jack. People say star grounding is the best way to do it, which is essentially having all ground points connect together at one spot, ideally the power jack. I didn't look toooo hard, but I believe what you need to be grounded are the input and output jacks and the PCB. So three wires going to the negative lug of the power jack, or connecting by the easiest way as your enclosure is laid out.