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Re: A-155 New/Old differences???

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  • Tim Stinchcombe
    Hi Richard, ... Newer 155 s have a small mod on them, which I believe is to stop it stepping more than one step when manually clocking it (and it s also the
    Message 1 of 7 , Jan 1, 2004
      Hi Richard,

      > Does anybody the difference in circuit design that would cause this
      > effect? Can I easily modify my newer A-155 to behave the same way?

      Newer 155's have a small mod on them, which I believe is to stop it
      stepping more than one step when manually clocking it (and it's also
      the thing that stops you clocking it very fast!). Underneath 'Board 4
      (Controller Board)' (one of the small ones), on your newer 155 you
      should see a capacitor and resistor soldered together and bridging a
      couple of pins on an IC. I suspect this mod may be what stops newer
      ones behaving this way. I know Bakis (for one) has removed this mod
      on his 155's, so perhaps if he is listening he can quickly try
      clocking it with a sawtooth to see if it does clock 'randomly'?
      (It'll save me getting my soldering iron out, but I will carry on
      looking at it to see if I can figure the exact mechanism out...)

      Tim
    • Tim Stinchcombe
      ... this ... also ... 4 ... a ... I can indeed confirm that removing this mod causes the behaviour you have observed with the sawtooth clock input,
      Message 2 of 7 , Jan 1, 2004
        > > Does anybody the difference in circuit design that would cause
        this
        > > effect? Can I easily modify my newer A-155 to behave the same way?
        >
        > Newer 155's have a small mod on them, which I believe is to stop it
        > stepping more than one step when manually clocking it (and it's
        also
        > the thing that stops you clocking it very fast!). Underneath 'Board
        4
        > (Controller Board)' (one of the small ones), on your newer 155 you
        > should see a capacitor and resistor soldered together and bridging
        a
        > couple of pins on an IC. I suspect this mod may be what stops newer
        > ones behaving this way. I know Bakis (for one) has removed this mod
        > on his 155's, so perhaps if he is listening he can quickly try
        > clocking it with a sawtooth to see if it does clock 'randomly'?
        > (It'll save me getting my soldering iron out, but I will carry on
        > looking at it to see if I can figure the exact mechanism out...)

        I can indeed confirm that removing this mod causes the behaviour you
        have observed with the sawtooth clock input, particularly noticeable
        with a falling sawtooth. I simply de-soldered the junction between
        the extra resistor and capacitor. The (comparatively) slow fall of
        the sawtooth causes havoc with the logic - it cannot decide if it
        should be 'high' or 'low', quickly flipping between both states until
        the ramp has come down enough for it to be sure. This 'noise' on the
        logic clocks the sequencer very fast, thus giving the appearance of
        randomly jumping backward and forward through all the steps. The mod
        prevents this from happening. (Without it, as previously mentioned,
        it is now possible to clock the sequencer at frequencies well into
        the audio range - nearly 6kHz from my A-145 at full bore!)

        Tim
      • TonyBlack [JohnnyBusca]
        Hello! I also own an old one, and I like that feature, but I m wondering if another thing is also fixed in the new version. When you use the trigger on the
        Message 3 of 7 , Jan 2, 2004
          Hello!

          I also own an old one, and I like that feature, but I'm wondering if
          another thing is also fixed in the new version.

          When you use the trigger on the first step, it keeps on triggering when
          you use the sequencer in combination with the A-199 midi interface. (midi
          clock --> sequencer clock, midi reset --> sequencer reset.)

          I often use the seqeuncer to trigger a bass kick on my SDS-800, and
          pressing STOP on my MPC2000xl results in a lot of kicks.

          Does this also happen in the new version?

          Best regards,
          JohnnyBusca
          > Date: Thu, 01 Jan 2004 11:46:19 -0000
          > From: "Tim Stinchcombe" <timothy@...>
          > Subject: Re: A-155 New/Old differences???
          >
          > Hi Richard,
          >
          >> Does anybody the difference in circuit design that would cause this
          >> effect? Can I easily modify my newer A-155 to behave the same way?
          >
          > Newer 155's have a small mod on them, which I believe is to stop it
          > stepping more than one step when manually clocking it (and it's also
          > the thing that stops you clocking it very fast!). Underneath 'Board 4
          > (Controller Board)' (one of the small ones), on your newer 155 you
          > should see a capacitor and resistor soldered together and bridging a
          > couple of pins on an IC. I suspect this mod may be what stops newer
          > ones behaving this way. I know Bakis (for one) has removed this mod
          > on his 155's, so perhaps if he is listening he can quickly try
          > clocking it with a sawtooth to see if it does clock 'randomly'?
          > (It'll save me getting my soldering iron out, but I will carry on
          > looking at it to see if I can figure the exact mechanism out...)
          >
          > Tim
          >
          >
        • Bakis Sirros
          hello tim, yes, i have removed this mod on one of my 3 newer a155 s and it behaves just like my older a155 s.i ll remove this mod soon,also, from my other two
          Message 4 of 7 , Jan 2, 2004
            hello tim,
            yes, i have removed this mod on one of my 3 newer
            a155's and it behaves just like my older a155's.i'll
            remove this mod soon,also, from my other two new
            a155's in order to be able to clock them in audio
            frequencies in combination with my a196's.
            bakis.




            --- Tim Stinchcombe
            <timothy@...> wrote:
            > Hi Richard,
            >
            > > Does anybody the difference in circuit design that
            > would cause this
            > > effect? Can I easily modify my newer A-155 to
            > behave the same way?
            >
            > Newer 155's have a small mod on them, which I
            > believe is to stop it
            > stepping more than one step when manually clocking
            > it (and it's also
            > the thing that stops you clocking it very fast!).
            > Underneath 'Board 4
            > (Controller Board)' (one of the small ones), on your
            > newer 155 you
            > should see a capacitor and resistor soldered
            > together and bridging a
            > couple of pins on an IC. I suspect this mod may be
            > what stops newer
            > ones behaving this way. I know Bakis (for one) has
            > removed this mod
            > on his 155's, so perhaps if he is listening he can
            > quickly try
            > clocking it with a sawtooth to see if it does clock
            > 'randomly'?
            > (It'll save me getting my soldering iron out, but I
            > will carry on
            > looking at it to see if I can figure the exact
            > mechanism out...)
            >
            > Tim
            >
            >


            =====
            Bakis Siros
            Parallel Worlds / Polariton
            Athens-Greece
            [Doepfer_a100] group owner
            http://www.rubber.gr
            http://www.ward12.com

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