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  • Leslie Modification



    Hi all! </P>


    I was thinking this morning about my Leslie. Is there a way on the Leslie 900 to get all sound, even the high treble tones, through the bass speaker. Whenever I unplug the top rotor speaker, I only hear the bass notes. I want everything trough the bass speaker. I'm guessing somthing with the crossover? Thanks everyone. </P>

  • #2
    Re: Leslie Modification

    It should absolutely be the crossover. Is it external in the 900 or built into the amp?

    Comment


    • #3
      Re: Leslie Modification

      The 900's amp is built in. But I have another question. On the amp, there is diffrent volume pots for the the treble and bass drivers. By turning down the bass driver volume, am I sending some bass tones to the treble driver, or simply lowering the volume. I think this is all cross over again.

      Comment


      • #4
        Re: Leslie Modification



        I think you're only lowering the volume.</p>

        Having a quick read of the manual, it says the x over is set at 800hz.</p>

        I'd download the 900 service manual from captain foldback and see if you cant bypass it or adjust it.</p>http://www.captain-foldback.com/Lesl...ers_manual.zip

        </p>

        Comment


        • #5
          Re: Leslie Modification

          I misunderstood the question earlier, the crossover I belive is built into the amp. I think if there is a way to manually adjust the crossover, that is is the way to go. Then everything would go to the bass speaker...

          Comment


          • #6
            Re: Leslie Modification



            G'day old Bean! Sorry I'm late to the piece, got a busy day on. However, the !5" speaker will do a terrible job trying to produce the trebles, you won't get a lot above the mids at all, even the high mids will be pretty sparse. </P>


            Why do you need it thru the bass rotor? Has your Treble driver burned out, are you wanting to mic it with only one mic, or is it just making too much volume in the treble? If the latter, of course you can drop the treble volume.</P>


            Ah! I've just seen the pic on Captain Foldback. The 900 has the horns in a separate cabinet, and no slow speed on the lower rotor. Could it be that the Horn cabinet is missing? It also has reverb speakers.</P>


            The active crossover (cos I THINK the 900s are the same as the 760 in this respect, though I may be wrong) takes the signal and splits it. This should also have a master volume on it. The split signals go separately to TWO amplifiers, one does the bass and sends to the rotor, the other goes out to the horns.</P>


            What you have on your hands, without the treble being produced, is a rewiring job!</P>


            You'll have to bypass the crossover board, sending the full signal to the bass amp board.</P>


            Does this sound in your sort of league?</P>


            I can dig out the schematics of the 760 and we could work thru the spots to solder if that's to your liking...</P>


            Cheers</P>


            -Brendon</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: Leslie Modification



              Hi Brendon!</P>


              The 900 is complete with the horn and bass rotor, and my treble driver is fine. I just thought it would be kind of cool to expierement with only one rotor, you know? But it sounds like it could be quite complicated, and a little bit over my head.</P>

              Comment


              • #8
                Re: Leslie Modification



                I'd have to think about it to see if it can be done easily. I also realised you explained the situation in the first post but I sort of skimmed it!</P>


                If you've ever played a home organ with an internal leslie, you'll probably have realised that a single rotor leslie is only half the fun anyhow!</P>


                My own frankenleslie is made up of two such units with crossover and different speakers, and soon to be 760 power amp as well. I could post up recordings of one rotor vs 2 rotors (as the thing evolved), you'll find it not quite so exciting as the full effect, though I think experimentation, if it doesn't ruin the thing in the process, is a good thing, I commend it!</P>


                This is after all how things get invented....</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


                • #9
                  Re: Leslie Modification

                  Thanks Brendon! You are absolutley right, half the leslie means half the fun! I appreciate your willingness to help, however! Speaking of single rotors, I believe Steppenwolf used a Leslie 125, which has only the bottom 2-speed rotor. But man, do they ever make that thing scream, especially in Born To Be Wild. Good stuff, man...

                  Comment


                  • #10
                    Re: Leslie Modification

                    Mm! Yum!
                    -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: Leslie Modification



                      Hi, also late into this fold. Interestingly I have a Leslie 130 (the decorator SS version of the 125 with a stationary tweeter) and have modified it with a DIY top rotor and additional amp &amp; 2 800Hz crossovers. Before I did that, I used an easy way to get the treble signals to fire into its bass rotor that may work for you with an additional speaker and switch. First I changed the tweeter to a louder high efficiency midrange with a good high frequency response. (A weak tweeter gets lost in the twirling down there.) Just wire your "third" speaker from the upper rotor's driver. Temporarily remove the woofer and install speaker #3 under the woofer using the holes on the brace over the bottom rotor and whatever washers, nuts bolts that will mount it on properly. You have to get it in the middle so it does not touch the speaker cone above it. You can test that by putting some chalk or powder on top of the smaller speaker #3's magnet. If it still touches, you can cut a jig ring out of 5/8" plywood and drill the screw holes through to raise the woofer higher and seal the sound in. I can find you pix on how do do this if you want. In essence, you have made the bottom speaker into a coax this way. If you hook in a switch between the rotor's driver and speaker # 3 you can turn it each on &amp; off whenever you want! Not sure if you should wire speaker 3 in parallel or series with the upper rotor driver to effect the ohms. I always get those figures mixed up, but with a switch I don't think it makes a difference as long as one is off and speaker #3 is the same omage as the upper rotor driver.
                      </p>

                      The BTBW Steppenwolf effect is great. I heard it was done with chorus 3, Leslie fast and a tube pulled from the 125's tube amp. That's one thing i wish I had on the 130 but maybe my soon to be installed Zener Overdrive will be able to emulate that!</p>

                      Bob</p>
                      http://www.petty-larceny-band.com/



                      Yamaha DGX-300
                      1959 Hammond M3
                      1961 Hammond A101
                      VB3 with M Audio Axiom
                      1975 Leslie 130 upgraded with V21 top rotor, tube amp, wood lower rotor
                      1972 Leslie 825 upgraded with top rotor, etc.
                      2011 Neo Ventilator
                      Casio WK-7500
                      Yamaha P50m Module
                      Roland VR-09
                      Casio PX-5S

                      Comment


                      • #12
                        Re: Leslie Modification

                        I agree with that. The only problem with our solid states is their total inabbility to go into a silky overdrive. I can overdrive my M3, but it sounds rigid, and cold compared to the a tube leslie, and plus, it's not to good for the leslie's speakers at high volume. By the way, why is it that a tube overdriven leslie sounds diffrent than a tube overdriven organ? To sort of mend this problem, Trek,has a mini tube overdrive board of sorts, and supposedly emmulates a Leslie 122 in overdrive almost exactly. I think it just involves some minor soldering, and you're good to go...

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