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  • Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



    RedOctober and BossBand Bob Asked if I could post up some of the emails I've had from Kon on making up his easy overdrive unit.</P>


    These especially apply to use on the M and L series, which only have one G terminal, how to use it on Hammond clones and Synths, and how to make an ultra simple unit to test if you like the sound or not.</P>


    I'm of course at work and will have to get back to this tonight or tomorrow. But are there any other folk out there interested in this?</P>


    I apologise to those who wanted the secret of putting manual tapering into a spinet. I'm getting there eventually, I have the recipe from kon, but the composing of elegant prose and adding pics is going to take time.</P>


    I'd also like to add that Kon will build these units for anyone who has the dough, and I can put you in touch with him.</P>


    That ingenious mad scientist proffessor DrFarndurk, one of our own here at the Organ Forum also has a magical touch with the soldering iron, and he's devising Hammond specific effects for us too, as we speak. If you have the desire to buy rather than build, you could alsodrop him a line toot suite!</P>


    There, that's two choices, you can't do better than that!</P>


    Now, on to the DIY stuff....</P>
    -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
    -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
    -DIY 760 FrankenLeslie/rat hideout-
    -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
    -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

  • #2
    Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



    I for one am interested, especially if that other cat over on Hammond_zone comes up with a PC board layout for the zener OD. (I can sort of use a schematic, but not really read one, if you know what I mean!)</P>


    cheers,</P>


    Scott</P>
    Nobody loves me but my mother,
    And she could be jivin' too...

    --BB King

    Comment


    • #3
      Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



      A PCB would sure make it easy to understand, Kon's drawing appears less simple than it really is. Once you start to follow the drawing you realise there's actually nothing to it.</P>


      I would post photos tonight, but our digital camera flash has started whiting out badly....I'll have to wait for a sunny moment tomorrow.</P>


      Here's Kon's super easy try out version....</P>


      </P>


      <FONT size=2>"Before fully building the complete passive zener diodes based overdrive unit you can try out a simplified version of it to see if you like the overdrive sound.</FONT></P>


      <FONT size=2>To make a simplified version of the overdrive unit all you need to do is to connect a few 3.3 volt rated IN2748 zener diodes in series and a 10 uf electrolytic capacitor in series with the diodes and then connect this across the GG outputs of the preamp in the organ , as shown further down below. </FONT></P>


      <FONT size=2>The 3.3 volt rated zener diodes and the 10 uf capacitor are very cheap to buy. The 10 uf capacitor can be a 16 volt or 25 volt rated electrolytic capacitor or non polarised capacitor. The polarity of the capacitor is irrelevant in this circuit.</FONT></P>


      <FONT size=2>You can connect this simple set up across the GG outputs with two alligator clips.</FONT> </P>


      <FONT size=2>Wire up six zener diodes back to back in series and then check the different levels of distortion produced by connecting one of the alligator clips to a different number of zener diodes. </FONT></P>


      <FONT size=2>When all six diodes are in series with the 10 uf capacitor , there is the least amount of distortion produced when the organ is played at full volume.</FONT></P>


      <FONT size=2>When four or three diodes are connected in series then a similar level of distortion as that of a stock Leslie 122 or 147 played at full volume is produced when the organ is played at full volume and the drawbars are pulled all the way out.</FONT></P>


      <FONT size=2>When two zener diodes are connected in series then a similar level of distortion is produced as that of a heavily overdriven Leslie 122 or 147 when the organ is played at full volume and the drawbars are pulled all the way out as heard on the 1970's albums by Uriah Heep ( Ken Hensley ).</FONT></P>


      <FONT size=2>When only one diode is in series with the 10 uf capacitor , there is the most saturated level of distortion and volume loss when the organ is played at full volume.</FONT></P>


      <FONT size=2>To test the overdrive distortion sound at a comfortable volume level , you can set the organ expression pedal at full volume and all the drawbars pulled out and then turn down the volume control of the Leslie or the external amplifier so that the volume level is set at a pleasant comfortable listening level , and then try out the simple overdrive circuit by connecting it across the GG outputs.</FONT></P>


      <FONT size=2>Here below are four diagrams of the simple version of the overdrive unit. The four diagrams show how to connect the alligator clip to the different number of diodes in order to get different levels of distortion when the organ is played at full volume.</FONT></P>


      <FONT size=2>If you like this overdrive sound then you can go ahead and build the full version of the solid state OD circuit that uses the master volume control and the bypass switch.</FONT></P>


      [I've edited these back to intended appearance, oras close as possible- 23May 09 - Brendon]</P>


      <FONT size=2>To produce a slight level of distortion:</FONT> </P>


      <FONT size=2>G output 1 ( Black wire ) G output 2 ( Red wire) </FONT>
      <FONT size=2>/\ /\</FONT>
      <FONT size=2>l l
      </FONT><FONT size=2>l Alligator clip 1 l Alligator clip 2</FONT>
      <FONT size=2>l l </FONT>
      <FONT size=2>l---ll----------&gt;l--l&lt;--&gt;l--l&lt;--&gt;l--l&lt;---l</FONT>
      <FONT size=2> 10 uf capacitor Six 3.3 volt rated zener diodes</FONT> </P>



      </P>


      <FONT size=2>To produce a similar level of distortion as a stock Leslie 122 or 147 played at full volume:</FONT> </P>


      <FONT size=2>G output 1 ( Black wire ) G output 2 ( Red wire) </FONT>
      <FONT size=2>/\/\</FONT>
      <FONT size=2>l l</FONT>
      <FONT size=2>l Alligator clip 1 l Alligator clip 2</FONT>
      <FONT size=2>l l </FONT>
      <FONT size=2>l---ll------------&gt;l--l&lt;--&gt;l--l&lt;----------l</FONT>
      <FONT size=2> 10 uf capacitor Four 3.3 volt rated zener diodes</FONT> </P>



      </P>


      <FONT size=2>To produce a heavy Uriah Heep style level of distortion </FONT></P>


      <FONT size=2>G output 1 ( Black wire ) G output 2 ( Red wire) </FONT>
      <FONT size=2>/\ /\</FONT>
      <FONT size=2>l l</FONT>
      <FONT size=2>l Alligator clip 1 l Alligator clip 2</FONT>
      <FONT size=2>l l</FONT>
      <FONT size=2>l----l l---------------&gt;l--l&lt;--------------l</FONT>
      <FONT size=2> 10 uf capacitor Two 3.3 volt rated zener diodes</FONT> </P>



      </P>


      <FONT size=2>To produce a heavily saturated level of distortion </FONT></P>


      <FONT size=2>G output 1 ( Black wire ) G output 2 ( Red wire) </FONT>
      <FONT size=2>/\ /\</FONT>
      <FONT size=2>l l
      </FONT><FONT size=2>l Alligator clip 1 l Alligator clip 2</FONT>
      <FONT size=2>l l </FONT>
      <FONT size=2>l----l l-----------------&gt;l----------------l</FONT>
      <FONT size=2> 10 uf capacitor One 3.3 volt rated zener diode</FONT> </P>
      <P mce_keep="true"></P>


      ..." Here ends transmission one!</P>


      From there its only a step to the rest. My PR40 didn't need the sweetening capacitors, though I did build them in I can't tell If they're working or not!</P>


      The PR of course having no speakers smaller than 12 inches, thehighscoming outoverly toppy is impossible.</P>
      <P mce_keep="true"></P>
      -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
      -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
      -DIY 760 FrankenLeslie/rat hideout-
      -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
      -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

      Comment


      • #4
        Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



        From there I asked Kon how the zeners are wired up to the 6 way switch in the full circuit and whether the try out version needed the G terminals to be unsoldered. He replied thusly:</P>


        "&gt;1/ with the simple try out circuit, do the G-G terminals still need to
        &gt;be unsoldered as they do in the full circuit?

        No there is no need to unsolder anything , you just simply connect the
        zener diodes in series with a 10 uf capacitor across the GG output
        terminals with alligator clips.

        &gt;2/ I don't seem to have any alligator clips handy. Can I get away with
        &gt;just winding the wire around it a few times?

        You can try this but it would be better to try to secure this with
        some sticky tape.
        You can buy alligator clips and appropriate lengths of wire from
        Jaycar Electronics. You need four alligator clips and two pieces of
        approximately 1 meter long wires so that you can connect the alligator
        clips to the GG output terminals and then be able to place the long
        wires with the other two alligator clips with the zener diodes on them
        on top of the organ so that you can then easily control how many diodes
        are connected in series whilst you are seated at the organ.

        &gt;3/ Since I won't be able to switch the OD off, what is your recommended
        &gt;number of zeners for the most versatile range of drive with clean at
        &gt;low volume? They always tell me I'm playing too loudly anyway, so it
        &gt;doesn't matter if I'm playing softly to get a clean sound at times!

        I recommend that you connect five or six 1N4728 3.3 volt rated zener
        diodes back to back in series followed by a 10 uf capacitor wired in
        series with one end of the diode network. Then you can connect one
        alligator clip before the 10 uf capacitor and after that you can
        connect the other alligator clip on to the number of diodes that
        produces the desired amount of distortion. Regardless of the number of
        zener diodes that you choose , the 10 uf capacitor should always be
        connected in circuit in series with the diodes.

        Three diodes connected in series will produce a similar level of
        distortion as that of an overdriven stock Leslie 122 / 147 when the
        organ is played at full volume.
        You can get a more saturated distortion and also get distortion at lower
        expression pedal settings if you connect one zener diode in series with
        the 10 uf capacitor. This would be useful if you are forced to play the
        C3 at lower volume levels but you still want distortion.

        As you do not have alligator clips at the moment , you can tie the end
        of one of wire around the external leg of the 10 uf capacitor a you
        can tie the other end of the wire around the zener diode that you choose
        depending on the level of distortion that you want. Tying the wire will
        be clumsy and awkward so therefore I strongly recommend that you buy
        the alligator clips. The zener diodes , the 10 uf capacitor and the
        alligator clips are all quite cheap at Jaycar Electronics.

        &gt;4/ if I find the time to try building the full circuit (or at least the
        &gt;bits I've got left after cannibalising them for other jobs!!) you
        &gt;appear to only have six diodes attached to the six way rotary switch. Is
        &gt;each one attached to the terminals of the switch, linked like a daisy
        &gt;chain from terminal to terminal, so that as you turn the switch it &gt;only
        &gt;cuts into a part of the chain?
        &gt;I THINK this is what you are showing, but I just want to be sure I'm
        &gt;not getting it wrong!

        Yes that is correct. The switch setting determines how many diodes are
        connected in series by switching between the different junctions of the
        diodes. Remember to wire the zener diodes back to back in series with
        the opposite sides connected to each other like this:

        10 uf D1 D2 D3 D4 D5 D6
        To G1 &lt;----| |-----&gt;|---|&lt;---&gt;|---|&lt;---&gt;|---|&lt;---
        /|\
        |
        o----------&gt; To G2


        &gt;Thanks for all of your help, I hope your time is all going well!

        I am currently working on an overdrive unit and during the weekend I
        hope to build an analog mVpp meter for Dave Hughes who sent me money to
        build the mVpp meter so that he can measure the output levels of the
        sinewave TG notes 13 to 91 and I also bought a set of MKT polyester
        capacitors so that Dave can replace the aged wax paper capacitors from
        the TG notes 49 to 91 and also the aged wax paper capacitors from the
        vibrato line box of his RT3 organ .

        All the best.
        Kon."</P>


        So there you go, Tonewheel1966 is going the whole hog and is living proof that Kon can build abloke agood millivolt meteralso.</P>


        I'll draw a picture shortly and show you how I interpreted his picture and wired up my rotary switch with the diodes....</P>


        ... But first, two more of kon's posts:</P>


        1/ how to attach it to the M or L series</P>


        2/ how to attach it to a synth or clonewheel</P>
        <P mce_keep="true"></P>
        -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
        -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
        -DIY 760 FrankenLeslie/rat hideout-
        -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
        -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

        Comment


        • #5
          Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



          -----Original Message-----

          Hi Kon!
          JonC3 from the hammond forum posted up this adaptation of your zener OD
          adapted for an M user.
          It's been there for AGES and you've probably already seen it, but I
          realised I've never asked if you have!
          http://organforum.com/forums/permali...ead.aspx#61591

          The Kon Zissis Zener Overdrive is well known, but M users probably don't
          realise they can adapt it to their organs.
          Have you thought about posting up an M variation on HamWiki, or even
          marketing an M version?

          Cheers!
          -Brendon</P>


          Hi Brendon.
          Thank you for the link.
          I saw JonC3's modified schematic some time ago.
          These days I do not use the "optional 200 ohms " resistor and I have
          also made changes to a few other parts of the circuit
          I have never experimented with an M-series organ and I don't access to
          an M-series organ so therefore I am not sure about the best way to wire
          up a zener diode overdrive unit on to a M-series organ.
          I would need to have access to an M-series organ so that I can
          experiment to work out the best way to wire up the zener diode overdrive
          unit before posting a schematic and an article on the internet or
          before considering marketing an M-series version of the overdrive unit.

          In the meantime I did draw up a schematic of an single unbalanced line
          version of the zener diode overdrive unit after Marco Forlano asked me
          if it can be used with a Roland VK7 organ. This version of the zener
          diode overdrive unit connects to the Roland VK-7 as an overdrive unit
          box after line out or the headphone output jack in the same way that
          you would connect an effects pedal after an electric guitar.

          Marco indicated that this version of the zener diode overdrive unit did
          work OK with his Roland VK-7.

          I have attached a schematic of this unbalanced line version of the zener
          diode overdrive unit.
          I cannot verify if it will work properly with an M- series organ but it
          might be worth trying it out.
          I do not know how safe it is for the output transformer or the output
          valves to connect this zener diode overdrive unit on to the speaker
          outputs of the amplifier.

          CAUTION
          The signal output levels coming from the balanced GG output terminals of
          the AO10 , AO28 etc preamp of the console organs are at line levels so
          therefore it is OK to use the 10 K Master Volume potentiometer but I
          expect that the very strong 10 watts - 20 watts RMS or higher speaker
          level signal will very quickly burn out the 10 K Master Volume control
          so therefore I think that the Master Volume control will need to be
          omitted if the overdrive unit will be connected to the speaker output
          of the power amplifier.

          In order to protect the amplifier or the output transformer from damage
          I think that it would be wise to wire up an 8 ohms or a 16 ohms 20 watt
          or higher wattage rated resistor in series with the overdrive unit
          input wire in order to prevent the possibility of the overdrive unit
          heavily loading down or shorting the speaker output signal to ground.
          All the best.
          Kon
          </P>
          -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
          -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
          -DIY 760 FrankenLeslie/rat hideout-
          -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
          -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

          Comment


          • #6
            Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



            Actually, I was mistaken, Kon didn't actuallyverify if JonC3's redrawn diagram works or not.</P>


            However, Here's Kon's diagram for the above circuit:</P>
            <P mce_keep="true"></P>


            </P>


            A full size printable version can be found here too:</P>


            http://i432.photobucket.com/albums/q...drivecircu.gif</P>


            Edit: 29/June/09:</P>


            Kon has verified this unit doesn't work and says he has built a working one using mixtures of zeners,LEDs and germaniums. I've decided to leave it up in case you want to experiment yourself!</P>
            -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
            -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
            -DIY 760 FrankenLeslie/rat hideout-
            -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
            -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

            Comment


            • #7
              Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



              Okay, here's how I added the zeners to the rotary switch in thefull circuit:</P>


              </P>
              <P mce_keep="true"></P>


              This is a LITTLE different than what Kon had in his circuit on Hammond Wiki, in that, position 1 isn't an "empty" setting on mine.</P>


              Kon's original circuit made allowance for aNO overdrive positionso that you can hear by itselfthe part of the circuit which simulates a damaged jensen driver.</P>


              Position 1 has all 6 zeners (back to back, note, not all the same way round) which means there's only a little overdrive at full swell. You still get to hear the crackly "shot" driver quite well anyhow!</P>


              To do it the way Kon had it in the original circuit there is only enough room for 5 zeners. </P>


              This worked for me!</P>


              I HIGHLY recommend adding the part of the circuit whichcreates the jensen dirt apart from the straight overdrive.</P>


              Let me know if you need any more drawings to explain the circuit!</P>


              Because I only own one half of my C3 and the other owner wants to keep it stock, I made the overdrive without the master volume controls.</P>


              They would only work, I think, when you permanently install the unit by unsoldering the wires from the preamp G terminals (yup, those ones with "G" stamped above 'em! I found where they were by looking at one of Farndurk's pictures of his A100 where he pointed them out for plebs like me!) and soldering the unit between the wires and the the terminals.</P>


              By omitting the master volume pots itmeans I don't need to have the unit installed permanently, but by using the alligator clips Kon had me go and buy, I can pop off the back of the organ, clip onto the G-G's and have the unit sitting on my cheek block with a couple of long wires running to it.</P>


              It was a fantastic night, the first night of performing with overdrive on the C3! It was prog-rock-heaven-on-earth.</P>


              The PR40 has been overdriving all along, but in a clean singing sustained way, no hair nor teeth.
              Now the folks don't say "Hey, we felt likewe wuz at church, heh heh!"</P>


              Which of course they were, one of those white "non-traditional" pentecostal types of church which has more traditions than they think, one of which is that they traditionally try not to sound traditional.
              Took a lot of aggressive posing to get an oldchurch organ allowed into the building and onto the stage!</P>


              An open minded, reasoning, thinkingperson is never so easy to find even in this "enlightened"day....</P>
              <P mce_keep="true"></P>


              -Brendoon the just as foolish, but in other ways.</P>
              <P mce_keep="true"></P>
              <P mce_keep="true"></P>
              -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
              -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
              -DIY 760 FrankenLeslie/rat hideout-
              -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
              -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

              Comment


              • #8
                Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



                Thanks, that's a great diagram. I was also having trouble visualizing the wiring from the schematic alone. Nice to have a commercial illustrator in these parts...</P>


                What mH value did you find worked best for the inductor in the Jensen-dirt part of the circuit? Kon said to experiment, but he did list avalue.I was thinking aboutomitting that part of the circuit to keep it simple. Now I may not.</P>


                You should make a recording or two with the C3/PR40/zener OD rig. I'd love to hear how it all sounds, and nowI'm curious about that Jensen dirt setting.</P>
                1955 M3 (in good hands!)
                1962 A100
                1942 BC
                too many other keyboards...

                Comment


                • #9
                  Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



                  I should add that the circuit Kon Drew up for the clonewheel has some important variations on the original which will make it easier to build for your own console or spinet:</P>


                  The Jensen dirt circuit is simplified: The switch is omitted. I found in my use with the C3 and PR40 that I liked the most crackly setting (I haven't ascertained if it was with 2 or 3 diodes. I expect it would have been the lesser number.) which I adjusted with the pot alone.</P>


                  Kon's simplified the sweetener selector. The moral is probably to buy the listed greencap capacitors and see which one suits your treble driver the best and install that by itself, as Kon also suggested in the original recipe.</P>


                  I see in this one Kon still has 5 zeners on the overdrive. It may be that the entire 6 isabout the same as having no zeners at all, aseach additional diode decreases the effect.</P>


                  I'm not sure if there are other changes.</P>


                  I also notice that while the Console version used the G toG terminals plus the ground for the two master volume pots, the clonewheel version uses G and ground, which suggests it may work fine for the M and L series organs.</P>
                  -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                  -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                  -DIY 760 FrankenLeslie/rat hideout-
                  -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                  -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                  Comment


                  • #10
                    Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



                    Bob can get the email alerts at work, but can't visit the forum (obviously!) and he asked me about what he needs to buy on the way home for the quick try.... I expanded it a bit into a slightly fuller version though... guess I can't follow a simple instruction!</P>


                    Here's Bob's qusetion and my answer:</P>


                    Hi Brendon, </P>
                    <DIV>I can't get on the Organforum at work but since I'm on break I'd like to ask you a few questions about your (or Kon's) Zener OD. (if you don't mind)</DIV>
                    <DIV>I've had good luck ordering electronics parts throughhttp://www.parts-express.com</DIV>
                    <DIV>But what type of zener diodes and rotary switch did you use? They have a whole bunch to choose from of both. From your sketch this looks like something I could do as I do know how to solder. What are the two objects on the two lines outside the rotary switch? Feel free to post these answers or my email as well. I may not be able to get on the forum until tomorrow to see it. I'm going to see Southside Johnny and the Asbury Jukes tonight!</DIV>
                    <DIV>Thanks</DIV>
                    <DIV>Bob</DIV>
                    <DIV></DIV>
                    <DIV></DIV>
                    <DIV><FONT face=Arial size=2>Hi Bob! </FONT></DIV>
                    <DIV><FONT face=Arial size=2>*The zeners are 1N4728, 3.3V 1W diodes, but parts express only seems to have 1N4729 3.6V 1W listed. Ask for the first, but get the second if that's all they have.</FONT></DIV>
                    <DIV><FONT face=Arial size=2>They have them listed for thirty something cents each. Get a dozen just to cover yourself.</FONT></DIV>
                    <DIV><FONT face=Arial size=2></FONT></DIV>
                    <DIV><FONT face=Arial size=2>*You'll need four alligator clips. They don't have them listed separately, but theres a pack of 10 test leads: Sku 360-150 for $2.95</FONT></DIV>
                    <DIV><FONT face=Arial size=2></FONT></DIV>
                    <DIV><FONT face=Arial size=2>*You'll need about 4 metres of wire to run from the preamp in the organ to where you can comfortably reach it. I didn't bother looking this up, you've probably got some at home, 2 lengths of anything above 1.5 metres. Kon suggested one length of twin core shielded for this trial version, I think. (twoif you're going to include master volume control later)</FONT></DIV>
                    <DIV><FONT face=Arial size=2>*You'll need a 10 uF capacitor, I believe this one will do for you: Sku 020-1142,costing a massive 9 cents.</FONT></DIV>
                    <DIV><FONT face=Arial size=2></FONT></DIV>
                    <DIV><FONT face=Arial size=2>*The rotary switch isn't necessary for the test version, but what you need is... hmm... not on parts express's list. Ask for a switch which can select at least 6 ways. If it does more than 6, I'll tell you how to adjust it....</FONT></DIV>
                    <DIV><FONT face=Arial size=2></FONT></DIV>
                    <DIV><FONT face=Arial size=2>*Look into the sweeteners later. They cut the harsh treble whic may result from a bright treble driver oreven a bright organ. </FONT></DIV>
                    <DIV><FONT face=Arial size=2></FONT></DIV>
                    <DIV><FONT face=Arial size=2>The damaged/dirty Jensen thing is cool too. That uses at least 2 or 3 zeners (included in the above dozen!) </FONT></DIV>
                    <DIV><FONT face=Arial size=2>also</FONT></DIV>
                    <DIV><FONT face=Arial size=2>* a 0.33uF capacitor (I think that can also be read 330 pF) this ought to do: Sku 020-1624 which costs 12 cents.</FONT></DIV>
                    <DIV><FONT face=Arial size=2>*</FONT><FONT face=Arial size=2>a 1K linear potentiometer. Sku 023-510, $1.48</FONT></DIV>
                    <DIV><FONT face=Arial size=2>* an optional "Two pole / two position centre off switch" can help you choose between the best jensen setting. This one LOOKS the coolest: Sku 060-087 at $2.09</FONT></DIV>
                    <DIV><FONT face=Arial size=2>but there's also this: Sku 060-083 at $1.75, a smaller, less flamboyant switch. DPDT means double pole double throw, which means it can choose between two different options and switch two separate circuits at once.</FONT></DIV>
                    <DIV></DIV>
                    <DIV><FONT face=Arial size=2>If you want it to look tidy, a box, plastic or metal, about 10cm square or even smaller: Sku 320-712 for $5.11 shouldbe bigger than you need, and give you space to spread out. I recommend drilling holes in the lid for the components. If you muff it, use the base of the box. The lid can be replaced with a flat panel, at any rate.</FONT></DIV>
                    <DIV><FONT face=Arial size=2></FONT></DIV>
                    <DIV></DIV>
                    <HR align=left width="25%" SIZE=1>
                    -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                    -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                    -DIY 760 FrankenLeslie/rat hideout-
                    -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                    -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                    Comment


                    • #11
                      Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects

                      <DIV><FONT face=Arial size=2>Ah! and sorry, the two objects on the lines out are: </FONT></DIV>
                      <DIV><FONT face=Arial size=2>going in to pin 1, the 10uF capacitor and a zener diode.</FONT></DIV>
                      <DIV><FONT face=Arial size=2>and of course, just a wire coming out of the centre pin.</FONT></DIV>
                      -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                      -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                      -DIY 760 FrankenLeslie/rat hideout-
                      -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                      -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                      Comment


                      • #12
                        Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



                        For those who want the shopping list from Kon's original circuit, here it is: </P>


                        PARTS LIST </P>


                        • Four pole / two position switch (bypass / overdrive on switch). x 1 </P>


                        [I wonder if this is necessary: the jensen dirt can be wound right out with the pot, and Kon's original design had NO zener on position one, which is essentially a bypass. Because I couldn't understand thetest version having 6 while the original circuit seems to only have 5, I wired the thing in such a way to have all 6. However, I've since learned the rotary switch can be adjusted to take up to 12 positions, so it could also beused to have all six PLUS a bypass. If you get a rotary switch get one that has only one or two poles, not a four pole switch.]</P>
                        <P mce_keep="true"></P>


                        • Rotary two poles / six positions switch (diodes selector, overdrive depth and sweetening capacitors selector). x 2 </P>


                        • Two pole / two positions centre off switch (Bass compression level and Jensen V21 clipping threshold selectors ) x 2 </P>


                        • Single pole / two position switch ( Sweetening capacitors on or off ) x 1 </P>


                        • 1K ohms linear potentiometer ( Jensen V21 dirt level control ) x1 </P>


                        • 10 K ohms linear ( or log depending on which has a more even volume tapering response along it's travel path ) dual ganged potentiometer (master volume) x 1 </P>


                        • 1.65 milli Henry, 0.04 ohms DC resistance inductor or little transformer to block the higher treble from passing through to the Jensen V21 dirt simulator. The actual inductor mH value may need to be experimented with in order to find the mH value that works the best. x 1
                        [Kon omits this part from the circuits he builds now. A lot of folk have trouble sourcing it anyhow.]</P>
                        <P mce_keep="true"></P>


                        • Knobs for the six position overdrive selector switch and the sweetening capacitor selector switch and the Jensen V21 dirt level and the Master volume control x 4 </P>


                        • 3.3 volts IN4728 zener diodes (overdrive clipping diodes and Jensen V21 dirt simulation ) x 9 </P>


                        • 100 uf 25 volt non polarised capacitor ( Capacitor in series with the diodes to prevent an unpleasant gnarly sounding inter modulation characteristic to the overdrive sound and also to allow the full bass distortion ) x 1 </P>


                        • 4.7 uf 25 volt non polarized capacitors ( Smaller mfd value capacitors in series with the diodes to prevent an unpleasant gnarly sounding inter modulation characteristic to the overdrive sound and also to block the lower bass frequencies from passing to the diodes thus resulting in less bass distortion and compression and a louder but cleaner bass to be heard ) x 2 </P>


                        • 0.068 mfd MKT or greenback capacitor ( sweetening capacitor 1 ) x1 </P>


                        • 0.1 mfd MKT or greenback capacitor ( sweetening capacitor 2 ) x1 </P>


                        • 0.150 mfd MKT or greenback capacitor . ( sweetening capacitor 3 ) x 1 </P>


                        • 0.220 mfd MKT or greenback capacitor . ( sweetening capacitor 4 ) x 1 </P>


                        • 0.330 mfd MKT or greenback capacitor . ( sweetening capacitor 5 and Jensen V21 dirt simulator capacitor ) x 2 </P>


                        • 0.470 mfd MKT or greenback capacitor . ( sweetening capacitor 6 ) x 1 </P>


                        • OPTIONAL 1 K ohms 1 watt resistors (Only needed for the Master Volume potentiometer if there is some hum when the master volume is set to a low volume position . If there is hum , the 1 K resistors are wired between the Pins 1 and the Pins 2 of the 10 K ohms dual ganged master volume potentiometer.) x 2 </P>


                        • OPTIONAL 200 ohms 1 watt resistors for current limiting protection in the event of a short circuit between the GG outputs x 2 </P>


                        • Six metres of twin core shielded cable (two or three metres each for the two new cables) </P>


                        • Metal box big enough to comfortably contain all of the overdrive circuit components x 1 </P>
                        -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                        -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                        -DIY 760 FrankenLeslie/rat hideout-
                        -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                        -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                        Comment


                        • #13
                          Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



                          And some photos of the circuit as far as I've made it. the full circuit needs room for two more pots only:</P>


                          </P>


                          And the inside.</P>


                          A disclaimer: my soldering is a bit messy. BUT if you install your bits in the LID and NOT in the BOX you'll fare much better!</P>


                          Not everybody is as daft as me.</P>


                          </P>


                          Those two big notches in the side aren't a soldering accident. They were for an earlier project which needed some hefty cables to get into the box!</P>


                          Cheers! </P>


                          Brendoooon.</P>
                          <P mce_keep="true"></P>
                          <P mce_keep="true"></P>
                          -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                          -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                          -DIY 760 FrankenLeslie/rat hideout-
                          -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                          -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                          Comment


                          • #14
                            Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects

                            [quote user="redoctoberff"]


                            Thanks, that's a great diagram. I was also having trouble visualizing the wiring from the schematic alone. Nice to have a commercial illustrator in these parts...</P>


                            What mH value did you find worked best for the inductor in the Jensen-dirt part of the circuit? Kon said to experiment, but he did list avalue.I was thinking aboutomitting that part of the circuit to keep it simple. Now I may not.</P>


                            You should make a recording or two with the C3/PR40/zener OD rig. I'd love to hear how it all sounds, and nowI'm curious about that Jensen dirt setting.</P>


                            [/quote]</P>


                            Crumbs Red!</P>


                            I missed your comment there, somehow. Konsays he omits the inductor these days, and it also costsabout as much as the rest of the components together, from memory. I didn't end up using it, maybe in the future. Of course, excessive highs aren't a problem on the PR40.</P>


                            I'd just go with Kon's suggested one myself,if I buy it, I reckon he's done enough experimenting for the rest of us!</P>


                            Then jensen bit is cool. It sounds just like an overloaded dying driver crackling away!</P>


                            I'll try and get some recordings, but as I said, I haven't figured out to record this beast yet, and it's in a building which is often in use by others.</P>


                            cheers!</P>
                            <P mce_keep="true"></P>
                            -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                            -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                            -DIY 760 FrankenLeslie/rat hideout-
                            -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                            -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                            Comment


                            • #15
                              Re: Some Extra Info on Kon's Zener Overdrive, and a Nod to the Farndurk Hammond Effects



                              Here's the parts of the circuit labelled:</P>


                              </P>


                              If you look closely you can see that the overdrive part is the first part of the circuit, and each other part is just piggy backed on with a wire.</P>


                              Because this had no master pots, there was no ground needed, just an in and an out. I can draw each part out separately if folks want it. </P>


                              Just say so!</P>


                              In the jensen dirt thing I used two single-pole-centre-off switches (SPDT) because I didn't have a DPDT handy. It means I have to throw them both at once. I would just eliminate this switch altogether, as Kon did for the clonewheel oneand use the either the 2 or 3 diode setting permanently, whichever gives the sound which suits best.</P>
                              -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
                              -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
                              -DIY 760 FrankenLeslie/rat hideout-
                              -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
                              -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

                              Comment

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