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    Unlocking the Yamaha E70



    I'm delighted to announce that I am now the newest member of the E70 club! [] My E70 arrived a few days ago from the UK, and it's in pretty amazing condition for a 30 year old instrument. Plus, to my great surprise, along with the owners manual was the original registration book, with the demo floppy record still attached!</p>

    I can see why FlametopFred got so excited about the possibilities of the E70. I'm having a lot of fun here at the moment! I've already come up with some nifty Blade Runner-type leads and pads, but I suppose a byproduct of the years spent on various synths leads me to the obvious question: how to unlock the E70 and gain custom control of ADSR, VCF etc? As Fred has already pointed out, it seems to have everything inside for heavyweight synth duties (the various 'Funny' sounds show off the filters nicely, and the chimes would seem to indicate a ring modulator is present), but at the moment everything is preset, with limited scope for adjustment, apart from a brightness (filter cutoff) slider and a switch for upper/lower sustain (a preset release amount).</p>

    Is anyone here familiar with the E70 on a technical level? I have the service manual and another manual called 'Electone PAS System Service Guide Analysis', but when it comes to electronics, I'm afraid I'm just an enthusiastic amateur... [*-)]</p>

    I haven't taken the back cover off yet, but from looking through the service manual, I have identified, among many others, circuit boards for preset control, VCF 1 &amp; 2, VCF 3 &amp; 4, and VCA. There are also 3 tone selector boards (the 3 piston presets?) and TPR1-4 (4 separate boards for these). I have no idea what these TPR boards are for, but according to the schematics, they appear to connect to the following: VCF attack clock, VCF 1st decay clock, VCF 2nd decay clock, VCA attack clock, VCA 1st decay clock, VCA 2nd decay clock, low pass filter, high pass filter, resonance low, resonance high, VCF initial level, VCF attack level, and VCA sustain level.
    </p>

    Is this the starting point? And if so, how and what to start with? []
    </p>

    Cheers</p>

    Frank</p>
    Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

    #2
    Re: Unlocking the Yamaha E70



    Well, it looks like I was wrong about the ring modulator for the chimes - the following is taken from the 'PAS system service guide analysis':</p>

    CHIMES</p>

    Using the tone color of Flute 4', the note of the depressed key (4'), minor 6th lower (6-2/5'), perfect fifth higher (2-2/3') and one octave higher (2') are produced simultaneously, and they decay within a certain length of time whether or not the key is held down.'</p>

    So, are there any potential E70 modders present? FlametopFred? Clavier? []</p>

    Cheers</p>

    Frank
    </p>


    </p>
    Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

    Comment


      #3
      Re: Unlocking the Yamaha E70



      I'm trying. My E-70 is in another state at the moment. When Ihave it again, I will get serious about modding it. I should warn you though, that I'm no electronics wiz. Let me know if you come across another PASS service manual. I'd really like to get one of those.</P>
      <P mce_keep="true"></P>


      -Joe</P>

      Comment


        #4

        Comment


          #5
          Re: Unlocking the Yamaha E70



          [quote user="Clavier"]</p>

          I'm trying. My E-70 is in another state at the
          moment. When Ihave it again, I will get serious about modding it. I
          should warn you though, that I'm no electronics wiz.[/quote] </p>

          </p>

          Neither am I! [:S] But hopefully we can get a few ideas going between us. I'll post any thoughts that occur to me from looking at the manuals, and hopefully we might get some input from those with more technical experience.
          </p>

          </p>

          [quote user="Clavier"]
          </p>

          Let me know if you
          come across another PASS service manual. I'd really like to get one of
          those.[/quote]</p>


          [quote user="dj-decaf"]</p>

          Would you please be so kind as to direct me to a source for the E-70 Service Manual? I have a User Manual, but no Service Manual--and my newly acquired E-70U needs some love! I've checked around a bit (Glinsky's site, etc.) but to no avail.</p>

          [/quote]</p>

          </p>

          The answer to both is eBay... I was lucky and spotted the E70 service manual and the PASS analysis guide about two months ago, and I purchased them both before I'd actually closed the deal on my E70. I had a feeling they might be pretty hard to come by, and it seems they are. I haven't seen any since, and I've kept an eye out in case any fellow E70 owners here might want them... []</p>

          Cheers</p>

          Frank</p>

          </p>


          </p>
          Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

          Comment


            #6
            Re: Unlocking the Yamaha E70

            [quote user="Clavier"]

            Let me know if you come across another PASS service manual. I'd really like to get one of those.[/quote]</p>


            There's one on eBay now. []</p>

            <span class="ebay">Item number:
            190220538245</span>
            </p>

            Cheers</p>

            Frank</p>
            Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

            Comment


              #7

              Comment


                #8
                Re: Unlocking the Yamaha E70



                Good stuff Tev! I'm glad one of you got hold of that manual. What's up with your E70? I don't know if I can help, but I can certainly check my E70 for you to let you know what should be happening in any particular area.

                I just had a conversation with a very good friend of mine, who happens to be an electronic engineer, professional acoustician, and a keen music and audio enthusiast. He's going to pay me a visit soon to meet the E70, and is fascinated by its potential as a synth.</p>

                So far, I think I have figured out the following:</p>
                1. The E70 is 7 note polyphonic for each keyboard, with 2 oscillators per note. The pedal keyboard is monophonic but also has 2 oscillators per note. It has 7 HPF, 7 LPF, 7 VCF and 7 VCA - per keyboard! This allows for fully polyphonic retriggering of VCF and VCA per note. I think there is also resonance control for the HPF and LPF. This is a potential megasynth! And I'm very grateful to FlametopFred for putting up the YouTube videos and putting me on the trail of the E70.
                2. Listening to the various presets, in particular the more complex, evolving 'Funny' sounds, the VCF and VCA appear to be very versatile. We have to tap into these somehow. There are 4 boards (TPR1-4) which provide various combinations of control voltages for the VCF, VCA, HPF, LPF etc, depending on the selected preset. TPR1,2 are for the upper keyboard presets, TPR3 for the lower, and TPR4 is for the pedal tones. These control voltages are then sent off to all the individual VCFs, VCAs etc for each voice of polyphony. There's a chart in the back of the PAS manual that lists all the presets and their control voltages.


                I spoke to my friend today about the idea of hooking up a bunch of pots across these voltage lines, and he said it should work, but it's not as simple as just cutting wires and hanging pots off them! The pots would need all 3 pins connected to properly control voltage, so grounding needs to be considered, and impedances matched. But he also said that it shouldn't be a problem. It's just a case of looking at the circuit diagrams and making some calculations in order to choose the right pots. </p>

                This would of course give a lot more control, but there is one flaw - it would be possible to reduce, but not increase, the control voltages already built in to the presets, which would seriously limit the sound shaping potential. It would then just be a semi-preset synth. So my proposal would be to sacrifice one preset (e.g. Flute), designate it as 'manual synth', and figure out what components would need to be changed on the associated TPR board to set all control voltages for that preset to their maximum (or minimum) allowable amount, hopefully giving us maximum tweakability!</p>

                Any thoughts? [8-|]

                Frank</p>

                </p>
                Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

                Comment


                  #9
                  Re: Unlocking the Yamaha E70



                  Ok, here's today's offering from me:</p>

                  Taken from the service manual 'E70 Overall circuit diagram (Analog section 1/2)', outputs from the TPR boards are as follows:</p>

                  VCF attack time
                  VCF 1st decay time
                  VCF 2nd decay time
                  VCA attack time
                  VCA 1st decay time
                  VCA 2nd decay time
                  VCF low-pass filter
                  VCF high-pass filter
                  Resonance low
                  Resonance high
                  VCF initial level
                  VCF attack level
                  VCA sustain level</p>

                  From this point, I have no idea how best to proceed. [^o)] Does anyone have any thoughts?
                  </p>

                  Cheers

                  Frank</p>



                  </p>
                  Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

                  Comment


                    #10
                    Re: Unlocking the Yamaha E70



                    Just thought I'd bring this old thread back to life, as my engineer friend recently paid me a visit, and instantly fell in love with the E70! We looked through the service manual and the "PAS system service guide analysis", and came to the conclusion that it would indeed be possible to intercept the various control voltages that are sent to the analogue filter and amplifier stages of the E70. This would allow us to build a synth panel to sit on top where the music stand is, and gain access to the parameters I mentioned in my previous post. That's a lot of extra VCF and VCA control, especially when those 13 parameters are available for upper, lower and pedal keyboards!
                    </p>

                    He suggested that the best way to proceed would be to design some new circuitry that could supply the full voltage range for each available parameter, rather than my initial idea of just hanging pots off the various voltage lines. It would involve cutting and rerouting a number of connections via a "preset/manual" switching system that would allow the E70 to work in either stock mode where the voltages are set by the presets, or manual mode, where the voltages are supplied by the new board(s). He also insisted that any mods we make must be undo-able, and that the
                    E70 must not be harmed in any way, and can be returned to stock by
                    simply unplugging the connectors running to the new panel and plugging
                    them back into each other.</p>

                    We have, however, come unstuck regarding waveform selection. This appears to be handled digitally by the E70 and is set according to the selected preset, and he reckoned it would be far too difficult to attempt to intercept those signals. We decided that the best way to proceed would be to use the presets for waveform selection, and the synth panel for VCF and VCA adjustment.</p>

                    If anyone here is knowledgable regarding the inner workings of the E70, please chime in! It would be good to know if we're on to something here, or if we're just barking up the wrong tree, so to speak![]</p>

                    Cheers</p>

                    Frank
                    </p>
                    Hammond C3 & Leslie 122, Yamaha E70, Lowrey MX1

                    Comment


                      #11
                      Re: Unlocking the Yamaha E70



                      Wow...what a great reborn of old E70.</P>


                      Make it more synth-like~</P>


                      would add a lot of fun and potential to the sounds.</P>


                      I also love my EX1~</P>
                      My favorite E.organ are: GX-1, FX-20, D-85.
                      I have EX1, DK40B, C605
                      And lots of synth,
                      YAMAHA's Synth Endorser

                      Comment


                        #12
                        Re: Unlocking the Yamaha E70



                        Congratulations Dr. Funk.</p>

                        I have just received yesterday the
                        Service Manual for both the D-85 and E-70. I actually sat in the
                        backyard reading them, drooling over the fold-out schematics.
                        Schwing! </p>

                        I think a lot can be done, and I have been
                        thinking about mods. I want to think a little while, and study
                        the schematics before diving in. But to start with I want to
                        change the audio outputs ~ and tap the audio outs before they get
                        combined in the internal mixer. Seems to be separate pre-amps for
                        the Drum Machine, the Upper &amp; Lower Orchestra, the Flutes, and
                        maybe a couple other places. This is cool and will help in my
                        recordings.</p>

                        There is also a few different places to add
                        some LFO's .... like the WAH (footswitch). Which might be the
                        best place to experiment. Be nice to get a little LFO that has
                        different shapes (TRIANGLE, SAW and SQUARE) and so on.</p>

                        There
                        is a sample + hold generator, which I did not know about ... trying to
                        figure out why that is, what it does, and also how to modify.
                        Next I want to look at the Coupling switches.</p>

                        I've also had
                        another think about the DIGITAL Control .... and wonder at what point
                        the KEYBOARD is a digital keyboard, and where does that signal go
                        exactly. Much to be learned.</p>

                        But much fun can be had with careful modifications.</p>

                        [quote user="dr funk"]</p>

                        I'm
                        having a lot of fun here at the moment! I've already come up with
                        some nifty Blade Runner-type leads and pads, but I suppose a byproduct
                        of the years spent on various synths leads me to the obvious
                        question: how to unlock the E70 and gain custom control of ADSR,
                        VCF etc?

                        </p>

                        another manual called 'Electone PAS System Service Guide
                        Analysis', but when it comes to electronics, I'm afraid I'm just an
                        enthusiastic amateur...[/quote]</p>

                        Do you think it would be possible
                        to have a PDF scan of that PAS guide? ? I can compensate you for
                        copy costs and postage.</p>

                        I haven't taken the back
                        cover off yet, but from looking through the service manual, I have
                        identified, among many others, circuit boards for preset control,
                        VCF 1 &amp; 2, VCF 3 &amp; 4, and VCA. There are also 3 tone
                        selector boards (the 3 piston presets?) and TPR1-4 (4 separate boards
                        for these). I have no idea what these TPR boards are for, but
                        according to the schematics, they appear to connect to the following:
                        VCF attack clock, VCF 1st decay clock, VCF 2nd decay clock, VCA attack
                        clock, VCA 1st decay clock, VCA 2nd decay clock, low pass filter, high
                        pass filter, resonance low, resonance high, VCF initial level, VCF
                        attack level, and VCA sustain level.
                        </p>

                        Is this the starting point? And if so, how and what to start with? []
                        </p>

                        It
                        is the starting point. I would love to contact an old Yamaha
                        designer or engineer. Mostly to ask about the digital components.</p>

                        </p>

                        </p>

                        Comment


                          #13
                          Unlocking the Yamaha E70



                          One thought that I had was regarding the Wah Footswitch ~ that it
                          would be the ideal place to start with an LFO or other controller.</p>

                          Also,
                          I was thinking last night about using the pull-out drawer section as
                          the other place to experiment with. Those presets are useful, but
                          I think would be more useful to use as entry points for the
                          modifications. In that drawer, there is of course a slider for
                          the filter. Should be a simple place to add either a jack for
                          foot-control (filter pedal) or perhaps an LFO.</p>

                          </p>

                          Later
                          on I want to look at adding a pressure/velocity keyboard. Perhaps
                          one of the early DX-7 61-note keyboards would work. Then a simple
                          matter of connecting the pressure to something like the wah-footswitch
                          for keyboard response on the filter. And then you would really
                          have a good CS-80 keyboard feel.</p>

                          Huh? Why yes, people do call me insane. Why do you ask?</p>

                          Comment


                            #14
                            E70 Magic

                            [quote user="dr funk"]

                            I just had a conversation with a very good
                            friend of mine, who happens to be an electronic engineer, professional
                            acoustician, and a keen music and audio enthusiast. He's going to
                            pay me a visit soon to meet the E70, and is fascinated by its potential
                            as a synth.[/quote]</p>

                            This wild, and encouraging. Very
                            interested to see what you guys come up with. Keep me in the
                            loop, please! Together we should be able to really unlock the
                            latent magic that's been laying dormant in the E-70. Likewise I
                            think we can help out DJ-Decaf.</p>

                            </p>

                            The E70
                            is 7 note polyphonic for each keyboard, with 2 oscillators per
                            note. The pedal keyboard is monophonic but also has 2 oscillators
                            per note. It has 7 HPF, 7 LPF, 7 VCF and 7 VCA - per
                            keyboard! This allows for fully polyphonic retriggering of VCF
                            and VCA per note. I think there is also resonance control for the HPF
                            and LPF. This is a potential megasynth! And I'm very
                            grateful to FlametopFred for putting up the YouTube videos and putting
                            me on the trail of the E70.
                            </p>

                            Thre has to be a way to
                            unlock the potential. The guts are there. I think the
                            potential is there for sure ... we can get (very) close to creating
                            something like a Super-CS80 or something that comes close to what the
                            GX-1 was all about. Different, for sure ... but maybe a whole new
                            beast.</p>

                            It was something I had thought about for a long time ....
                            distilling in my brain for years. Everytime I would see an old
                            Electone with buttons that looked like the CS-80, I would wonder.
                            Then I chanced upon the D-85 and got closer, then found the E-70
                            and confirmed my hypothesis. Insanity can sometimes be a good
                            thing ...[]</p>

                            Listening to the various
                            presets, in particular the more complex, evolving 'Funny' sounds, the
                            VCF and VCA appear to be very versatile. We have to tap into
                            these somehow. There are 4 boards (TPR1-4) which provide various
                            combinations of control voltages for the VCF, VCA, HPF, LPF etc,
                            depending on the selected preset. TPR1,2 are for the upper
                            keyboard presets, TPR3 for the lower, and TPR4 is for the pedal tones.
                            These control voltages are then sent off to all the individual VCFs,
                            VCAs etc for each voice of polyphony. There's a chart in the back
                            of the PAS manual that lists all the presets and their control
                            voltages.
                            </p>

                            Very cool ... and it may be possible to tap
                            into those presets ... that's why I was thinking of looking at the
                            pre-set drawer. That might be a great resource ... either to
                            re-wire in some way, or tap into.</p>

                            So my proposal
                            would be to sacrifice one preset (e.g. Flute), designate it as 'manual
                            synth', and figure out what components would need to be changed on the
                            associated TPR board to set all control voltages for that preset to
                            their maximum (or minimum) allowable amount, hopefully giving us
                            maximum tweakability!
                            </p>

                            </p>

                            That's what I was
                            thinking too ... either the Flute or the Harp sounds. On the
                            CS-80, there are two top-panel banks, which are the non-preset
                            sounds. Remember that the CS-80 itself has preset sounds.</p>

                            One
                            of the keys to the CS-80 is not so much the flexibility of the sounds
                            (the presets) but the keyboard control and the filter, etc. So
                            having one bank on the E-70 being flexible or 'user programmable' would
                            be good ... that's what I was looking at the Drawer for ... that would
                            give all the sliders that we need to access the synth sounds.
                            Maybe ! ![] </p>

                            That whole drawer could become our
                            programming answer. Which might be something I would move to the
                            top of the console, rather than be right where I am playing from the
                            hip.</p>

                            So maybe your friend can also look at the KEYBOARD side of
                            things ... and the CONTROL. I had this thought that we could
                            install two DX-7 61 note keyboards and get aftertouch in some way ...
                            which could trigger some of the Filter stuff.</p>

                            </p>

                            </p>

                            Comment


                              #15
                              E70 Digging Deep



                              The other question for your tech friend, Dr. Funk, is concering the
                              Transposition setting. I would love to (like on the CS80) have
                              one of those be a 5th transpose. I think it's actually 5 1/2,
                              like on the CS-80. That would allow some pretty cool tones
                              ... tones which recreate on the E-70 by blending the flute tones.</p>

                              Come
                              to think of it ... maybe instead of using the drawer sliders for
                              programming the synth section, why not exchange those: that is - use
                              the console flute sliders to control the synth parameters. Then
                              relegate, or relocate the Upper and Lower Flute sounds to the
                              drawer. Hmmmmm ....</p>

                              we do need engineering help .. but I think the potential is huge.</p>

                              </p>

                              Comment

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