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Anti-chuffing mod

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  • unrevealed_source
    I m wondering how many people reverse the anti-chuffing mod after using the radio for a while. I did. I found the loud boink very annoying, and it was a
    Message 1 of 8 , Aug 1 6:20 PM
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      I'm wondering how many people reverse the anti-chuffing mod after using
      the radio for a while.

      I did. I found the loud boink very annoying, and it was a bother to
      turn the volume control down just to change bands or turn the radio on
      and off. More seriously annoying was the pop-pop-pop when you're
      tuning across a crowded band. (Synthesizer locking and unlocking). I
      prefer the chuffing to those two noises.

      I did try the resistor trick, and actually tried quite a few different
      values. Anything that mutes the boink and the popping also brings back
      the chuffing. I think the best overall configuration for normal use of
      this radio is stock, without the mute mod.

      But that's just my opinion. I'm wondering how many other people have
      reversed it, finding that the side-effects were worse than the
      chuffing. Anyone?
    • Mentalo
      I did the mod a long time ago and have been very happy with it. It s odd that I don t recall anything negative happening after the mod. I also did the fine
      Message 2 of 8 , Aug 1 8:20 PM
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        I did the mod a long time ago and have been very happy with it. It's odd that I don't recall
        anything negative happening after the mod. I also did the fine tuning mod and would never
        want to go back to the stock configuration.

        Fred
      • phil6han@netscape.net
        That is why I installed a convenient on/off switch for this mod. Sometimes its better on and vice versa. ... [Non-text portions of this message have been
        Message 3 of 8 , Aug 1 10:09 PM
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          That is why I installed a convenient on/off switch for this mod.
          Sometimes its better on and vice versa.

          jneese@... wrote:

          > I'm wondering how many people reverse the anti-chuffing mod after using
          > the radio for a while.
          >
          >
          >
          >



          [Non-text portions of this message have been removed]
        • WS8E
          I agree with Fred. I m not even sure I know what you mean by boink.............
          Message 4 of 8 , Aug 2 5:52 AM
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            I agree with Fred. I'm not even sure I know what you mean by boink.............

            On Fri, Aug 1, 2008 at 11:20 PM, Mentalo <mentalo@...> wrote:
            > I did the mod a long time ago and have been very happy with it. It's odd
            > that I don't recall
            > anything negative happening after the mod. I also did the fine tuning mod
            > and would never
            > want to go back to the stock configuration.
            >
            > Fred
            >
            >
          • adenton0
            I had read reports of the boink and decided to do the chuff mod right. The chuff happens because the muting is too early in the gain chain so the small
            Message 5 of 8 , Aug 4 7:27 AM
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              I had read reports of the boink and decided to do the chuff
              mod "right." The chuff happens because the muting is too early in
              the "gain chain" so the small offsets generated when the muting
              transistors switch are too amplified.

              So I "bit the bullet" and moved the two transistors to the top of the
              volume control. I cut the circuit traces and installed 3.3k resistors
              in series with the volume control (between the end of the control and
              C231/C232) and relocated the two NPN transistors to shunt the junction
              of these new 3.3k resistors and the vol controls to ground. Their
              base circuit remains the same (I relocated the resistors also).
              Everything gets mounted on the foil side of the main board, below the
              RF board ("under" it if you've just opened the case, toward the upper
              left).

              The results are fantastic. There are no chuffs nor boinks. This is
              because the signal level is MUCH higher at that point, so the mV-level
              offsets generated by the transistors are basically inaudible. Another
              way to visualize it is that the "chuffing" from them now gets 'cut
              down' by the volume control (in the stock configuration, it doesn't).

              It is quite doable. Sometime I should open 'er up and take some pix
              and write it up as a real 'mod'.

              If anyone wants to try this, be *very* sure to note the pinouts of the
              muting transistors BEFORE you unsolder them -- i.e., which "leg" goes
              to ground. You could also just grab two new NPNs from your junkbox --
              any "general purpose" transistor would be OK.

              The only "penalty" here is that the max. volume is lowered VERY
              slightly as the 3.3k and 50k of the volume control now reduce the
              audio. This reduction is tiny and IMHO is totally unnnoticable.

              Adam

              --- In Sangean803@yahoogroups.com, "unrevealed_source" <jneese@...>
              wrote:
              > I'm wondering how many people reverse the anti-chuffing mod after
              using
              > the radio for a while.
            • phil6han@netscape.net
              Adam, Are the transistors you refer to Q309 & Q310? I would like to see a photo. I might try a version of your plan. Phil adenton@bear.com wrote: ... So I
              Message 6 of 8 , Aug 5 9:51 PM
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                Adam,
                Are the transistors you refer to Q309 & Q310? I would like to see a
                photo. I might try a version of your plan.
                Phil

                adenton@... wrote:

                ...
                So I "bit the bullet" and moved the two transistors to the top of the
                volume control. I cut the circuit traces and installed 3.3k resistors





                [Non-text portions of this message have been removed]
              • unrevealed_source
                I guess my take on all that is that if you are moving transistors, or performing other modifications of that magnitude, maybe a different radio altogether is
                Message 7 of 8 , Aug 22 1:27 PM
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                  I guess my take on all that is that if you are moving transistors, or
                  performing other modifications of that magnitude, maybe a different
                  radio altogether is in order.

                  I mean, the 803A is a very good radio for what it is and for the price
                  you can pick one up on eBay, but it's hardly worth doing major surgery.

                  If you know what stations you want to listen to and can tune right to
                  them, this is a good radio. But for "cruising the bands" and trying
                  to find new signals, it's just not that great, with or without the mods.
                • Anthony Lenzo
                  ... price ... surgery. ... trying ... mods. ... you think huh?
                  Message 8 of 8 , Sep 3, 2008
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                    --- In Sangean803@yahoogroups.com, "unrevealed_source" <jneese@...>
                    wrote:
                    >
                    > I guess my take on all that is that if you are moving transistors, or
                    > performing other modifications of that magnitude, maybe a different
                    > radio altogether is in order.
                    >
                    > I mean, the 803A is a very good radio for what it is and for the
                    price
                    > you can pick one up on eBay, but it's hardly worth doing major
                    surgery.
                    >
                    > If you know what stations you want to listen to and can tune right to
                    > them, this is a good radio. But for "cruising the bands" and
                    trying
                    > to find new signals, it's just not that great, with or without the
                    mods.
                    >
                    you think huh?
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