Home › Forums › Vintage EHX › Help needed identifying a Small Stone (v2/v3 mix?)

Viewing 5 posts - 16 through 20 (of 20 total)
1 2
  • Author
    Posts
  • January 14, 2009 at 10:57 pm #90726
    MrHaroldA
    Member

    This could be useful, but I’ll first try to place a good opamp or jfet based buffer before the SS…

    Quote:
    From R.G. Keen

    The loss of volume when engaged is correctable in the Issue J Small Stone
    by changing the gain of the two-transistor preamp at the input of the circuit.

    There are two 4.7K resistors at the emitters of the input transistors. One
    (R7) goes to ground from the emitter of Q1, the second (R42) connects the
    emitter of Q2 to the emitter of Q1. Those two resistors set the feedback gain
    of the two-transistor compound.

    Increase the 4.7K between the emitters (R42) to increase the gain. Start with
    10K. Be aware that this will affect the stage biasing, so the headroom may
    be affected; I don’t think this will really be a problem.

    The silly thing *ought* to have included a JFET buffer in front of it for
    buffered bypass and a bit of gain in the first place.

    August 26, 2009 at 10:47 pm #100944
    volkan
    Member

    I m sorry for that my bad english
    resistance in the picture, such as burns and broken pots. broken cables. I do not know where I would connect the cables.
    Can you help please?
    goruntu118.jpgw1280.png

    May 18, 2019 at 10:00 am #125245
    Airell
    Participant

    Hello,

    My question is similar to this one and the board also seems the same, so this might be the same answer (an H model). So it seems multiple boards, only a hand full of cases (V3 this one).
    There is an extra capacitor on the back and I think some later soldering on one of the IC’s which might indicate a repair.

    The pot reads 1378048 (1980 week 48), and there is a difference with the original poster’s board that it has an extra TCI-A4H 94HB written on it.

    I will add some pictures, but I didn’t take the unit completely apart to get an image of the top of the board.

    Regards, Airell.

    May 18, 2019 at 10:02 am #125246
    Airell
    Participant

    Print side 1

    May 18, 2019 at 10:02 am #125247
    Airell
    Participant

    Print side 2

  • Author
    Posts
Viewing 5 posts - 16 through 20 (of 20 total)
1 2
  • You must be logged in to reply to this topic.