First build - Fuzz First

[ipoo2]

Hey all first post but have been lurking for a little while  

I posted this in another forum, but have got no replies. Hoping for better here! Here goes...

I am building my first pedal, a Fuzz Face! Here is the schematic, its the NPN one, http://pigeonfx.com/layouts/layoutff.html

Wire it all up and then had sound 'clean', but when engaged no fuzz and no sound. I realised that one jack was wired incorrectly. Fixed that, same result.

My worry now is the switch, an alpha latching switch. This has 1 2 & 3 on the right hand side, aligned with the three lugs on the right hand side. Looking at the schematic, I assumed "1" was the top right? Is this correct? Also, the two lugs connected on the switch, I connected using a tiny bit of wire. Is that OK?

Thanks in advance!

As an aside, this was a great resource to learn about jacks and how to wire them! http://gaussmarkov.net/wordpress/pa...acks-and-plugs/

[lopsided]

not sure if it helps, but check this link http://www.generalguitargadgets.com/diagrams/switch_lo_dpdt_input_grd.gif?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a it is the same bypass wiring but at least for me it is more easy to read what goes where.

and check this: http://www.diystompboxes.com/smfforum/index.php?topic=970.0
it shows how switches work, it doesn't really matter if you connect something  to lug 1 or 3. Make sure the central lugs are right and that the relations of the other lugs are the same as in the diagram.
Also check the next picture. It is wiring for a 3PDT switch, but examine the jacks, to see whether you have the terminology of Sleeve, Tip and Ring right.

I connected using a tiny bit of wire

This should be fine. Make sure it doesn't touch any other lugs. I like to use a piece of isolation from a striped wire and pull it on a cut off lead from a resistor or something.

One last thing make sure your using an input cable with a mono jack, this wiring will not work if you insert a stereo jack.


Personally i prefer to test my circuits with as little wiring as possible. Obviously I need pots and a battery. Then I attach jacks with crocodile clips, and check whether the circuit works by itself.


Hope this helped a little.
l_s

[ipoo2]

Cheers lopsided, some interesting reading 

However, I have checked all wiring and it matches the diagram (the two links certainly helped) - yet no difference.

i.e. Its clean, so the bypass is working, yet nothing when engaged in 'fuzz mode' ! Its frustrating, but a nice learning curve! I guess it could be my soldering, the three wire into one lug, does not look great! I think tonight I will unsolder the jacks and attach using crocodile clips.

If that does not work I will need to learn how to take readings of the board using a multimeter!

[lopsided]

it might be worth to start with the multimeter before you start resoldering stuff. If you have one (if you don't, buy one, it can be any cheap digital multimeter), it is very easy way to find out whether the circuits itself is working. Good way to start is: set it to read DC, connect the black cable to ground of the circuit and check the voltages of all three lugs of the transistors with the red cable. When something doesn't work, this is really the simplest way to start debugging it.

If you already haven't, check this for a list of suggestion, what to do, when pedals don't work: http://www.diystompboxes.com/wiki/index.php?title=Debugging

l_s

[ipoo2]

Wow! Thanks again!! My bookmarks are filling up 

Luckily I do have a multimeter. Do I have to ground to the circuit or can I use the aluminum project box? I read somewhere that you could use the negative terminal of the battery??

Any ideas what sort of readings i should be getting?

Thanks again

[petemoore]

  http://www.diystompboxes.com/wiki/index.php?title=Debugging

  Do I have to ground to the circuit or can I use the aluminum project box?. the box is conductive, all marked grounds are common ground, ie 'DMM beep', or 0.0v should can be tested/or measured between grounds.
   I read somewhere that you could use the negative terminal of the battery??
  NpN negative Gnd. ? = Gnd. Neg. connects to - of battery or power supply.
Any ideas what sort of readings i should be getting?
  The ones which you should be getting ! !
   It depends on the circuit bias, which is either off-base [ie theres a miswire int he circuit], somewhere close [ie Q2C bias resistor could use an adjustment] or right on [the FF sounds great, and Q2C is somewhere's towards the middle of the supply voltage...5 or 6volts from Gnd.
  Q1C is 'unusual' in that this is a 2 transistor feedback loop amplifier stage...see runoff grooves voltages, something like ~1.2v here.
   Should bias ~easy and boost a lot.

[lopsided]

Yes, in our context Ground means the negative terminal of the battery  or a place on the circuit, which is directly connected to it. On the layout you posted a sign for ground is bellow the lower left corner of the board (the triangle made of 3 lines), so that place should do.

One more advice, after you hopefully make this work, consider building the beginners project found on this side. It is an easy booster, but the building process is very well explained. So it will help you to gain the very basic knowledge necessary for building other projects.

l_s

[ipoo2]

Defo think I will do the beginner project next. I think I have jumped in to the deep end on this one! It has been a massive learning curve, as I found out yesterday. I had assumed the pots on the schematic was looking at them top down rather than from the bottom 

So, rewired and I have fuzz! Sort off, I only get something when the linear pot is turned to max... Is this a dodgy pot problem??