Shruthi-Synthesizer and my "WAVE 1"


#21

Good job! I think if you ever distribute/sell your synth, people will be thankful for that.


#22

Thanks. It’s a long way until the end of my development :slight_smile: The Sounds on my synth have now more “click”.

The next step on my work is: Loading wave-files and sound-parameter from SD-CARD and USB-Stick with ALFAT board.

Greetings from germany


#23

Wow. I just listened to the youtube video and it sounds rather nice !

Congratulations.


#24

Hallo

Here pic from my enveloop. I have change the longest time for attack, decay and release a little bit more time (see pic).

All ENV-Parameters can adjust with midi-controller value 0-127.

Geetings from germany


#25

I just wanted to say: great work so far (sounds quite interesting and I’m really enjoying your live work in progress report here)


#26

Thanks. The next: I work now for SDCARD- and USB-Interface (see above).


#27

Hallo. There is new information in my webblog about shruthi and wave1: http://www.cczwei-forum.de/cc2/thread.php?postid=80248#post80248


#28

The touchscreen is a nice idea. But I can imagine that drawing the display takes some CPU time.


#29

No. The Touch-Screen have a cpu (ATMega) on board. I send short commands for touchbuttons and drawing lines and text.
The ALFAT-Board for SDCARD and USB-Stick have a Soc-Prozessor on board and i send short commands for reading and writing datas to SDCARD or USB-Stick.


#30

Will it be possible to draw waveforms or manipulate envelopes with the touchscreen?


#31

Hallo fcd72

That’s a good idea. This option comes in the future. I work now for the ALFAT-Board on my synth.
The data transfer is verry fast.

My idea is: My synth have a fast 8MByte SDRAM onBoard and you can loading a lot of Sample-Files from
SDCARD ore USB-Stick in my synth and play.

But there is still a lot of work so far. I’m only and i work a little bit every day on my synth.

My synth is my hobby and my love :slight_smile:

Greetings from Germany


#32

Hallo

I have the “ALFAT OEM board” connected to the AVR-Synthesizer (see pic) and programming first funktion as for example init SDCARD and USB-Stick, Format, read rtc-clock.

I have change the cap in the power supply circuit. The +5 Voltage was too little when I contact alfat on my synth. ALFAT Board need 5Volts for USB. For the sdcard there is an internal 3.3 volt regulator on ALFAT Board.

The next step is funktion for save and loding files to sdcard and usb.

Best greetings from germany


#33

Hallo shruthi users

I have change the power supply circuit for my synth. The old version has an 7805 Chip equipped with heat sink module and this was very hot. The new version has two DC/DC Converters for VCC +5 V and VCC +3.3V. The DC/DC Converters work fine without heat sink modul and the temperature is verry low.

Greetings Rolf


#34

I don’t think D6 and D8 are no longer needed ; but a protection diode like D4 would be indeed useful for the switching regulators, as they don’t like sinking currents (this will happen when the synth is powered down and your downstream capacitors discharge).

Do these switching regulators add extra noise on the DAC outputs?


#35

Hallo pichenettes

Thanks for your tips :slight_smile:
The dac outputs have no extra-nois because the MCU (32MHz Xmega with two dac’s) has a separate 3.3V power supply on ATMEL Xplained-Board. It is powered by the +5 V power supply with TSR 1-2450 chip. I think that the protection with diode of the DC/DC converter is not necessary, because data sheet says maximum capacity for output is 470uF. The cap in my circuit are not so high.


#36

> The dac outputs have no extra-nois because the MCU (32MHz Xmega with two dac’s) has a separate 3.3V power supply on ATMEL Xplained-Board.

Ah OK… so there’s still a linear regulator in the loop to clean things up!

> I think that the protection with diode of the DC/DC converter is not necessary, because data sheet says maximum capacity for output is 470uF.

I am not sure this spec is related to the problem I am pointing - and that this capacitance constraint is related to start-up / initial conditions issues. But in your board you don’t have much bypass capacitors anyway…


#37

Ok. I have test the ripple and noise of power supply.

VCC +5 V = 12mV, Nois 500KHz
VEE - 5 V = 5mV, Nois is not measurable
VCC +3.3 V = max 80mV (Touch-Display make high ripple when dimming backlight) 500KHz Nois


#38

So… my next step is a new concept for the panel in my synth “WAVE 1”. When i have work with my old panel (Touch-Display and one encoder), a lot of touch-function for adjust a sound. My new panel concept see the picture.

The new panel has five encoders. Four for datas (example: ADSR) and one for funktion. I think it’s better if I adjust a sound.

Greetings Rolf


#39

Is mode a button or encoder? If it’s an encoder you must be lefthanded :wink:


#40

It’s a Shruthi in a mirror ! :slight_smile: