Unlocking the Yamaha E70

[Ewaves]

Yes, you only have to connect the 3,9k resistor on the right, on the left you have to connect no parts, look to the LED symbol inside the ic, you have to connect it in parallel with the existed led, cathode to cathode and anode to anode, download the datasheet for pinout.
v out is collector and output, and emitter to ground, only +5 on resistor 3,9k.

Greetings

[Alejandro]

[Alejandro]

Hello Friends,

don't know if for the Star-Stop I can take the tension directly or if I have to put a resistance.
This is what I have done which is what I understood to Ewaves and it works perfectly, although the logic would have led me to another scheme ...

[Ewaves]

Hello Friends,

don't know if for the Star-Stop I can take the tension directly or if I have to put a resistance.
This is what I have done which is what I understood to Ewaves and it works perfectly, although the logic would have led me to another scheme ...

Well done !
Polarity is not reserved, and yes, for safety you can put a 4,7k resister in the 5v line to the middelpart.
When you put the plug in, and touch with the middelpart against ground, you have a short circuit.

[Alejandro]

Ewaves,

What you explained about the noise Marc and I were talking about yesterday. I have understood you perfectly, but you have also given me the necessary push, since what you have described is what I imagined to do, measure, achieve a signal of an adequate level, couple with capacitors, etc. But due to my ignorance in the behavior of electronics, sometimes I am afraid of doing something wrong.

It will be necessary to place some switches in addition to the potentiometer.

We want to do a similar thing in the CSY, and it is about adding the flute sounds to the VCF and VCA of the synthesizer part, so that they behave with the same envelope (now they behave as in an organ, neither attack nor decay d nothing...)
I did tests 3 months ago and managed to introduce the sound with a capacitor to block, etc.
but at the entrance of the VCF the tension of the synth was 20 times greater than what it could deliver with the flutes.
Later I put signal later in the circuit and the balance was balanced enough, but the synth sounded twice and I had to lower the volume of the synth a lot.

Marc's idea was that we could input the output signal of a mixer, and thus in the future, in addition to the flutes, we could add noises, etc.
Speaking with an acquaintance, he told me to be very careful with these things, that they would change impedance values in these parts of the circuit and you had to calculate well ...

Thank you very much for these clarifications, I get down to work.

[Ewaves]

No, its not necessary to put a switch, because on the lowest level on the pot the level is ground, maybe you will need a logarithmic pot for it, if the level is on a great part of the pot less, and in the end everything, you have to find out.
A lineair pot = 8,5K A
A logarithmic pot = 8,5K B
Schematic's for Csy1 I have are not that clear, I have lo look with my scope in it, on an certain moment, but for now I go for the E50.
And yes, be very carefully with wat you are doing, by any doubts do nothing, you don't want to break the exotic parts, we are not circuit modders !

Greetings

[dr funk]

Thanks Ewaves, and thanks Alejandro for the wiring diagram! Would the extra 4.7k resistor go between the +5V power and the switch on the diagram?

[Ewaves]

Yes

Greetings

[Alejandro]

Corrected scheme

[dr funk]

Great, thanks Ewaves and Alejandro!

One more question: did you add another switch (start-stop) or were you able to connect to the E70 drums start-stop switch to start & stop everything together?

[Alejandro]

For me you can ask all the questions you want ... I have not put it, I did tests with the cables ... but we will have to study what is best ... I may even install a foot switch.

[dr funk]

Ok, I understand. Thanks also for the updated wiring diagram, Alejandro! 😀

[Alejandro]

Hi Ewaves, actually the 3 potentiometers you drew in that scheme are not 8.5k but B. 5k 

[Alejandro]

Ewaves,

One question, put the noise at the input of the VCF and also all the waves together ... it will not be more work for the VCF than there are only the waves?, unless we have measured the level and equalize it ... I mean, there will be no attenuate the waves somewhat so that the sum is approximate to when there was no noise? I hope you understand me.

Greetings.

Alejandro.

[Alejandro]

I am aware that the presets have 4 gain lines, because some are made with two different waves and they add more signal, I made a modification there and put a potentiometer to adjust the gain. I will make a measurement of all the waves + noise, but without saturation, and I will try to limit the total signal in some way with noise and waves, I prefer to lose a little level and work safer.