Fuzz pedal makes vague choppy sound and makes loud buzz :/

[Jage]

Hi guys,

My first time here and also my first time building a pedal (i got it into my head i wanted to make one and am now really frustrated after many failed attempts)

I have got to the point where when i plug my guitar in and turn on it makes a very loud buzzing sound (also buzzes but less loud when the switch is off). I can hear the guitar very faintly and it just sounds like a clean signall through the buzzing noise!

I am following a design from a youtube video by Oskar Jungell (youtube diy fuzz pedal and its the blonde bearded guy with a red tele)

Literally don't know where to begin debugging this, hence why i'm here asking the wise people on this site! Any tips would be HUGELY appreciated as im about ready to give up

Thanks
Jage

[bloxstompboxes]

First off, Welcome Jage! Glad to have you here. Next though, to get that pedal working, we need more info. Read this below and you will get more assistance. Probably should pst in the "Building Your Own Stompbox," section too to get more views.

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[Cozybuilder]

Start by reading the debugging section and comparing your build to the schematic. If you post photos of your build, someone here may be able to help. It sounds like you have a ground problem at the least.

Here's the referenced schematic:


Edit-
I just spent a few minutes breadboarding this- its a surprisingly good sounding fuzz! The 5K pot gives a good range from mild OD to all-out fuzz. For a seven-component fuzz, this is a lot of bang for the buck.

[Jage]

Ok, as far as i can tell i've got everything in the schematic. (Note: i used his drawing of the wiring too) i'm gonna try and post some pictures in a second (cant do it on my phone). Ive layed the components on a board but the rest is just point to point wires!

[Jage]

Edit-
I just spent a few minutes breadboarding this- its a surprisingly good sounding fuzz!

haha this makes my 4 weeknights and a saturday in the garage to no avail seem pretty useless lol

ok, so I went from this version as I found it alot easier to look at and I can just trace the wires. The only thing i assumed is that the black wire going to ground actually goes on the negative terminal on the 9v battery?



As mentioned above I put some stuff on a plain board, but wired everything point to point so my pictures are probably just a heap of wires :/ I tried to make them as clear as possible by separating wires here and there!:

Components in the board (I used a 4.7 pot instead of 5 for the gain other than that i think the transistor i used a BC547 transistor as i couldnt find the one he had):

http://www.aronnelson.com/gallery/main.php/v/diyuser/IMG_7264.JPG.html

http://www.aronnelson.com/gallery/main.php/v/diyuser/IMG_7265.JPG.html

http://www.aronnelson.com/gallery/main.php/v/diyuser/IMG_7266.JPG.html

http://www.aronnelson.com/gallery/main.php/v/diyuser/IMG_7267.JPG.html

[Cozybuilder]

Jage-
Your photos don't show up. Did you post them to a web-based host first? (Photobucket, Imgur etc). Once posted, use the URL for the photo between the "insert image icon", "" (above the first smiley face emoticon).

Two things jump out- the transistor is oriented EBC, legs down, in the drawing. And the orientation of the 3PDT should be holes line up top to bottom. Verify the function with your ohm meter- its easy to orient the switch 90 degrees off.

The ground from the battery is connected to the sleeve of the stereo jack, the rest of the grounds are connected as shown. This is your battery on-off switch.

[Jage]

thanks for the fast response I used the Aronnelson site as recommended on the forum rules, I've changed them to url so hopefully they should work now.

I had to rewire the transistor today as I did have it the wrong way but now it should be fine.

I've also used a 4pdt switch which should be the right way round (i'll check for good measure now though!). Could it be a faulty part maybe?

[Cozybuilder]

The switch looked like it was oriented correctly.

This could be done on a 4x6 perf:

[Jage]

Ah, that would perhaps have been a more efficient way of setting out the board!

Switch is definitely on the right way, which means unfortunately I still haven't found the fault Could any particular parts be the cause of this kind of problem. Also what parts are not that important if they get changed (i.e can i swap out for a different value of capacitor or another model of transister?)

Sorry for all these questions, first build is stressing me out! Thanks for all your help thus far :D

[Cozybuilder]

Try drawing out what you have now, all components on one side, and use a different color to make the connections, as it exists. It looks like there are some wiring errors.

[Jage]

ok, so here is my schematic from what I actually have made. I can't spot the differences from the original though, and unfortunately don't understand the electricals behind it well enough yet to know what else could be wrong :/ any advice?

http://www.aronnelson.com/gallery/main.php/v/diyuser/IMG_7269.JPG.html

Thanks
Jage

[Cozybuilder]

Jage-
It looks like the problem is at the switch and caps. The input tip should go to the 220nF cap, and cap 2 (100nF) should go to lug 3 of the Volume. It looks like these are reversed.

[Jage]

oh my -_-, I think my frustration at previous attempts has blinded me. I think you've solved my problem! I shall correct this tomorrow as soon as I can and report back the findings. Hopefully I can get the same good fuzz that you achieved!

Thanks so much, Will report on results tomorrow
Jage

[Cozybuilder]

I look forward to hearing how it works out for you. 2N5088 sounds great in this too- I'm sure any medium to high gain transistor would be fine.

[duck_arse]

Jage - in that wiring dia with all the colours, the output jack is missing a ground connection.

[cozy - what transistor on your perf?]

[Cozybuilder]

Hi Duck-
I tried MPSA18, 2N5088, 2N5089- all sounded good. EBC legs down looking at flat side. Jage's photo showed the missing ground, so I didn't comment on it.

[Jage]

Ok, UPDATE: it now stops buzzing when the switch is off, but it still just buzzes and i cant hear the guitar when it is on. :/

With respect to the missing ground on the output. If i connect the shield on the output jack to the negative of the 9v battery, would that be correct??

Again, sorry for my beginner knowledge and thanks so much for the help

[Cozybuilder]

The battery negative lead goes to the sleeve of the input jack. All other grounds are connected together. When you plug into the input jack, connection is then made between the battery and the ground circuitry.

I'm puzzled why it doesn't work if you rewired the input from the switch to C1 (220nF), and moved the output at C2 (100nF) to Volume pot lug 3.

[Jage]

MAJOR SUPER UPDATE (plus 1 simple question): IT WORKED!!! I connected the sleeve of the output jack to the ground circuit on i believ lug 3 if the gain pot! And it certainly makes a sound Thank you so much for all your help from the start!! It's really made me want to keep going and maybe build another one trying out different parts in the near future

My one additional question was in terms of adding an indicator led to the circuit. Would it work to attatch the led to the positive terminal of the 9v battery and to one of the 2 spare middle pins in the switch?

Edit: sorry, basic thing. I believe it should be positive 9v to ground so it's broken when there is no input   thanks again so much for all your help on this! I'll be around on this site much more in the future me thinks

[Cozybuilder]

Glad to know you have it working now 

For an LED connect the battery pos to a current limiting resistor, then the resistor to the LED anode (+). Connect the LED cathode (-) to one of the unused pairs of the 4PDT, same side of the switch as the connections to the circuit. Wire the middle lug to ground. If you use a standard diffused red 3mm LED, probably 2K2 will be fine for the resistor. If you use a super bright clear blue, then 47K will be small enough, and it uses a lot less current (longer battery life).