Rolfdegen
Senior Member

Hello Edwin. Thanks for the good tips. I will check it. Greetings. Rolf

Power circuit for my teensy synth.. Link: https://forum.pjrc.com/threads/63255-New-Teensy-Synth-quot-Shruthi-2-quot?highlight=Teensy+Shruthi

The 1st draft in 3D

The design is not final yet :confused:

New "Jeannie" layout.. The rectangle below the display is the Fx module. This is put on the underside. Greetings. Rolf

Hallo Chris :) Thanks. When I'm done with the development I will upload my project to Githup. Its free. I use the Arduino Lib for the graphics. Parameter settings are converted for a resolution of 128. Look at...

Hello Friends.. Our progress cannot be stopped. This time we really accelerate. The Fx PCB is ready. Now we has started to route the "Jeannie" mainboard. I'm curious.. Fx board

Hello friends.. We have started to route the boards. I'm curious how big they will be. Fx board Greetings from germany. Rolf

Hello and have a nice Sunday :) There are a few changes in the circuit diagram. The DAC output (PT8211) on the Teensy Board has an active 32KHz LowPass filter. This reduces high-frequency interference signals at...

Hello again.. :D The prototype of the Fv-1 circuit is now completely soldered and works flawlessly. Will be a little smaller later because of SMD and relocation of the power circuit (+/- 5V) to the main board.

Sorry.. double post

Hello Tomas I am using a 6N137. Pin 7 is Monitoring node and does not have to be connected. Greetings from germany. Rolf

Hello friends :) It is progressing. Corona also has something positive. You spend more time at home and on your computer. Before I start laying out the boards, I want to know if everything works. I may be there a...

Thanks for your good ideas. There is hardly any space left on the circuit board. It's open source and you can change it if you want :)

Hallo Daniel That is not provided in Jeannie. We want to build this synthesizer very small and inexpensive with good sound. But maybe in an XT version with many pots ans knops :mit den Augen rollen: Gruß Rolf

Hallo friends.. Here are complete Jeannie circuit diagram with FV-1 card. PWM1-4 and SPIN1-4 are Spin FV-1 control lines. MCU unit Control unit

Hallo.. This function is not intended. But the key that was pressed first becomes active. Today I got the FV-1 chips. These are 28 pin SMD chips but it's not difficult to solder. For comparison, an 8-pin IC. ...

The Spin FV-1 effect module is mounted on the back of the Jeannie board. This is an old PCB version. I built it into my other DIY synthesizer "DEGENERATOR". Here are sound examples from Degenerator Synth with...

Hallo friends :) This is the control unit from Jeannie. For the button query, I use an ADC input to save output lines on the Teensy Board. The LED Driver IC8 is controlled via the same SPI bus as the ADC chip but...

Yes that would be good. The envelope code would have to be changed for this :confused:

Hello friends.. I adjusted the envelope Attack time from 1ms to 0.25ms . That makes more punch with percussion sounds. 1ms

Small update .. :cool: The envelopes also get a delay and hold parameter. These two parameters will be added to the graphic later. In addition, there is a peak meter in the header for checking the output level on...

Hello again.. :) My next step is to implement the Filter Envelope and Amp Envelope A better video of envelopes and filters is coming. Best Greetings from wuppertal in germany. Rolf

Hi Frank Thanks for your tip. It's a prototype. The layout isn't final yet. Some buttons, joystick, volume control and LEDs are added.

The filter page The sound interference comes from rendering with MP4 in Video Deluxe. Video: https://youtu.be/2QipRkolZk0 Greetings. Rolf

Hello again.. It is progressing. I am currently programming the filter page and to display the filter fade from LowPass to HighPass. Greetings Rolf

Hello again.. :) I exchanged the LED for two 1N4148 diodes. This reduces the voltage drop behind the LM317. Greetings Rolf

Hallo again.. Voltage output on the LM317. Since the LM317 cannot regulate its output to 0 volts because of its internal Uref of 1.25V, With its voltage drop, the LED ensures that the output voltage begins to rise...

Sorry.. Its IC6 LM317

I still want to save processor power for future functions ;)

@Frank My Teensy Synth blog in deutsch: https://www.sequencer.de/synthesizer/threads/avr-synthesizer-wave-1-de-generator.87599/page-22 :)

Hallo.. AntiPop circuit without relay.. IC5 LM317 slowly increases the operating voltage for the audio amplifier. Audio file: First sound with anti pop and second without

Thanks for your good explanation. :)

Hello .. Today the ordered components came. The relay for the audio on circuit is really small and sweet :cool: The relay then hardly takes up any space on the circuit board. I save on a control line on the...

I think S/N ratio will get a little better with a PCB board. Usability is also very important in my development :) I want to build a small synth with good usability (e.g. Shruthi). Greetings. Rolf

Hi Mark Thanks for your analysis. I made a new measurement (Balckman-Harris 1024 point) with the same audio file. The 1st picture shows only the noise without sound. The 2nd picture shows the complete audio file. ...

Hallo friends.. Today i makes a Noise and interference level measurement by Jeannie. My Behringer Mixer Xenyx QX1222 makes more noise. Jeannie is better than -78dB noise. Audio File:...

This is my current breadboard

I recorded a few more test sounds from my JEANNIE. All with active boost :cool: Audio file: https://drive.google.com/file/d/1cNen9axOS54KOhjGq50l2iQ2f6VHPUtq/view?usp=sharing Greetings. Rolf

Hello loving Teensy friends. I changed the output amplifier and power supply a bit.The amplifier had too much interference from the 9V supply at the output. For this reason I now use a 12V power supply and sieve...

@Luni I tried ResponsiveAnalogRead, but there is also noise in my synth. The best way is an external ADC. There is only 1 bit of noise. My projekt blog here:...

I want to test it with the relay. :confused:

Hallo Daniels Thanks for your tips. I want to think about it :confused:

When the operating voltage is switched on, the capacitor C18 / C19 is charged via the resistor R20 / R21. This prevents a switch-on pop at the output. After 500ms the relay is switched to the audio output. Teensy...

Hi friends.. Circuit proposal with Relais e.g. Omron G6K-2F-Y-TR DC5 G6K-2F-Y-TR DC5

Hallo Freunde .. Versuchte es erneut mit 79L05 und 78L05 als Spannungsquelle für den TL072. Aber auch nicht so schön (siehe Bild). Sie können das Ein- und Ausschalten meines Audiomixers deutlich hören. Mmmm ...

Hallo friends.. Small measurement setup with TL072 and symmetrical power supply. Blue the output voltage at the TL072. Yellow the -9V voltage on the TL1054.

Thanks for the tip :)

Hallo friend.. I have now built a new BassBoost circuit for my Synth. Works very well. You now have the option, by assigning the free switching contacts on IC5a with other resistors R9/R17. change the strength of...

I tried MQS. But there is no good quality with high notes. 16bit sound is much better. I will stay with PT8211 with 4x oversampling. It's a better choice for good sound and cost. Greetings from germany. Rolf

I'm not sure yet if the bass boost and LP filter circuit works. An internal bass boost in the Teensy (via a filter function) overdrives the internal effects and output mixer.

Thanks for your tips. Shruthi uses symmetrical supply voltage. I want to do without that. I want higher output level for bass sound. Teensy mixers and effects overdrive with bass sound.

That would be a nice dream :rolleyes: Maybe there will soon be a "Teensy 4.2" including a 16-bit DAC :confused:

The PT8211 can only be bought on ebay. The MSQ (PWM) output is not a good alternative for me. I want to build a nice synth with 16Bit sound. I would like an equivalent alternative for the i2s output on the Teensy 4.1...

Hallo friends :rolleyes: I am looking for an inexpensive alternative to the PT8211 DAC for the Teensy 4.1 ? Thanks and Greatings from Germany. Rolf

Yes. Could you change that in Teensy Synth "Jeannie" ? Thanks :)

circuit diagram Subject to change. Greatings Rolf

Yes. Its a Teensy Synth. The name of my Synth is "Jeannie" from "I Dream of Jeannie" an American fantasy sitcom from the 60s :Ö Greatings from germany. Rolf My german block:...

Hallo Daniels Jeannie has digital filters. State variable 12dB filter (SVF) with continuous mix between LP and HP (provides notch filter) and BP Cutoff freq and resonance. Four inputs on the MCP3208 are for...

Hello and hopefully to a happy new year 2021 I continued to work on the "Jeannie" and the selection of different waveform banks added. With the free WaveEditor from Synthesis Technology I have the different wave...