Home Forums GuitarPCB Build Support PUTB Loud Buzz – No Fuzz

This topic contains 3 replies, has 2 voices, and was last updated by  wilkie1 2 months, 1 week ago.

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  • #6056

    Joe
    Participant

    I just finished assembling my PUTB.

    The bypass works OK, the light changes color, but when the pedal is engaged I get a loud buzz sound that is louder than the guitar.  The buzz goes away when the level is all the way down, and goes up as you increase the level.  See the video.

    I did not add the three disc capacitors that were optional to reduce hum.  Aside from adding those, and maybe re-flowing the solder joints I’m kind of clueless about how to troubleshoot this.  I guess I can verify all the ground paths per the schematic.

    I’d appreciate any advice.  Here is a short video of what I get.

    https://www.dropbox.com/s/i10j0xv4h5ads6p/IMG_0203.m4v?dl=0

     

    #6057

    wilkie1
    Moderator

    Look at the IN and OUT pads on the circuit board.  The is a small letter “T” next to the pads that carries the signal.  The pad next to that is a ground pad.  You have the wires reversed on both the IN and the OUT pads.

    #6063

    Joe
    Participant

    Thanks Wilkie1, that was exactly the problem.  I missed the “T” on the board.

    So I have a functional Fuzz now, but it’s not quite right.  The attack doesn’t seem to do anything.  It makes a very slight change in the sound, but it’s really subtle.  The level seems really hot too (I’m 99% sure I didn’t get them reversed, I checked them with the multimeter before I mounted them).  At about 1:00 on the level knob the pedal is roughly as loud as when playing in bypass.

    Also, I get a lot of noise from the unplayed open strings.  For example, fret the 6th string, play a note, release it, and there is a lot of buzzing (fuzzing?) from the other strings that weren’t played or fretted.  If I dampen them it immediately stope.  There isn’t any noise when the pedal is on.

    The bias on Q3 is too hot too, with the trimmer all the way clockwise I still have -7.8 volts.

    #6064

    wilkie1
    Moderator

    Regarding the attack, confirm the value, orientation and soldering of C8, P1 and R5.  Other than that, I am not sure why the attack is not to your liking.

    If you have unity level at about 50% rotation of the VOL pot, that is very typical of many pedals.  Most designs are not intended to dime the VOL in order to reach unity.

    Undesired hum or noise when the strings are not being touched is usually a matter of poor shielding of pickups, cables or pedal enclosure.  Look for a poor ground connection.  Re-soldering may disclose a bad joint. Try installing those 3 ceramic caps even if you do not have the exact values.

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