Pages

▼

Sunday, 3 February 2013

Tufnel Distortion

From Beavis Audio Research: Finally something that actually does go to eleven. I love the 386 power amp chip. It is incredibly versatile. As the engine behind the Ruby, Little Smokey, and Noisy Cricket amps, it is the best bang for the buck single-chip amplifier.
But it is more than that: it is also used widely in distortion effects.




at

14 comments:

  1. onthetundra4 February 2013 at 06:19

    Gain pots are backwards and the tone pot isnt doing anything.

    ReplyDelete
  2. onthetundra4 February 2013 at 07:37

    The cap coming off of pin 5 of the second chip needs to come down one more row for the bright pot to work.

    ReplyDelete
    Replies
    1. mirosol4 February 2013 at 09:05

      The gains have been swapped - but i don't agree on the bright pot.
      http://www.beavisaudio.com/projects/tufnel/Tufnel_Schematic_V1_1.gif

      Pin 5 of the IC2 has two caps connected - 100n which goes to Volume 3 and Bright 1&2. The other cap, 4n7, connects to 10R resistor going to ground.
      +m

      Delete
  3. STAALHAAR14 March 2013 at 18:32

    Tone pot ( Bright ) dont work on mine Is this Verified ?

    ReplyDelete
  4. STAALHAAR14 March 2013 at 18:34

    What is the far right Cut doing ? I Dont get it..

    ReplyDelete
  5. mirosol14 March 2013 at 18:50

    Tag says unverified.

    That cut seems to be leftover, so it has no function.

    Compare this to schematic: http://www.beavisaudio.com/projects/tufnel/Tufnel_Schematic_V1_1.gif
    +m

    ReplyDelete
  6. STAALHAAR15 March 2013 at 17:24

    I Have seen the schematic ... And the tone pot still don´t work

    ReplyDelete
    Replies
    1. mirosol15 March 2013 at 17:55

      So you agree that the layout is on point with the schematic?

      You could try out what onthetundra said earlier: The cap coming off of pin 5 of the second chip needs to come down one more row for the bright pot to work.
      +m

      Delete
  7. STAALHAAR15 March 2013 at 17:30

    Anybody out there...Who can verifi this with the tone pot working

    ReplyDelete
  8. STAALHAAR15 March 2013 at 18:01

    I tried what onthetundra sugested but the tone is still not working...Thanx for your fast online support...
    Greetings from Copenhagen Denmark

    ReplyDelete
  9. dexxyy5 August 2013 at 00:48

    This looks to be correct as per the schematic but the bright pot is definitely doing nothing. I've snipped the bright pot off and it still sounds the same, guess Dano might have made a boo boo on the schem.

    ReplyDelete
    Replies
    1. mirosol5 August 2013 at 07:10

      Sure looks like it. You interested in modding the schem for working bright control? :)
      +m

      Delete
    2. dexxyy5 August 2013 at 16:13

      It seems bright enough for my taste, I might do switchable input/output caps ala the dam meathead for a bit more balls tho'. It is crazy mental loud tho :-)

      Delete
  10. Jupnitski7717 July 2015 at 12:51

    I did my own vero layout of this one ages ago, based on that same schematic.
    My version acts just the same, Bright doesn't do anything. And to me, two separate gain controls are just waste of pots. So I substituted those gain pots with a 10kB dual pot.
    A dual 10kB was all I had, so I recommend trying a dual 1kB or 5kB pot, because with 10kB the distortion starts changing in the last half of the pots rotation. I'll report the results when I have a dual 1kB to play with.
    And I made the Bright pot into a typical filter pot, because it was too easy :)
    Just reverse the connections of Bright-3 and Bright-1&2 on the board AND remove connection of Volume-3 from the board and connect it to Bright-1&2.
    Here's a link from where you can find the idea (though in my mod there's no resistor after that filter pot):
    http://www.electrosmash.com/proco-rat-analysis/pedals/distortion/pro-co-rat-distortion.html

    ReplyDelete