Home Forums GuitarPCB Build Support PUTB v3? HELP! (solved) Reply To: PUTB v3? HELP! (solved)

#7026
Barry
Keymaster

The extensive guides for beginners are on the Guides Page. Since all builds are almost exactly the same we simply do not repeat this large amount of redundant information for multiple reasons. That said it is always available to anyone and unlike other places we have a dedicated forum to help. Go to our Guides Page by using the big Red button on either the Form Home Page or the actual Home Page of GuitarPCB

See image below:

 

 

To answer the first question:

We just upgraded the design to v3 which was entirely cosmetic. I simply did not add a second board photo yet as I have been in the hospital. That said onto the build questions:

The V3 layout only has some some components moved around to make more space for the transistors to fit but no part numbers were changed. The In and Out wiring is exactly the same and all parts are populated exactly the same using the board silkscreen as your layout guide. We would have gladly clarified this before building or during building since we are here to help and do not assume we are going to berate you.

Our unique In/Out wiring scheme additionally is exactly the same for all pedals. Again beginners can find these Guides on our Guides Page for reference or even print them out since they are a “one size fits all”.

Probable Build Issues:

  1. I cannot tell exactly from the photos provided but you cannot lay the solder side of the board against an enclosure without some type of non-conductive protective barrier (electrical tape) or the bulging solder joints will short out against the enclosure. Likely why you would have “crackly noises” and other issues.
  2. You absolutely must Bias a Fuzz pedal for it to sound correct (this is a fine adjustment) so it is not really considered a beginner pedal however it is not that hard to do. You must take voltages using your DMM and testing the Collector with the Red probe and place a black probe on any ground and take a voltage reading and simply adjust the trimmer till you get the required reading. (again see our Guides Page).

Here is a copy and paste from the actual build doc:

In order to have this circuit sound like a Tone Bender, you must use transistors in the recommended gain (hFE) ranges and bias the circuit. There is a 20K trimmer potentiometer on this board designed to help you adjust the bias. Using your digital multimeter (DMM), measure the voltage between ground and the collector pin of Q3, and turn the trimmer to the right until your DMM reads around -7V. The board layout has each pin of the transistors marked if you look closely enough (zoom in or print this document). ​The bias can be adjusted up or down by a volt or so to your personal liking​. There have been reports of some original vintage tone benders having the bias as high as -8.5V, while other germanium fuzz pedals like the fuzz face were biased at around -4.7V. In addition to a slight change to the tone, a larger negative bias value will increase the circuit’s output level, which may factor into where you decide to set the bias.

As you can see this circuit will not function without Biasing. This is the same for any PNP Germanium Fuzz project available on any site.

If you need further help after checking over the Guides on the Guides Page we will need voltage readings and just ask the basic questions of what you do not understand about biasing or whatever.

I hope that helps.