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  1. T

    Which version of Teensy for a DIY synthesizer?

    I am currently building something similar, so maybe you can save me some experimentation time. How are you doing the Teensy to Teensy communication. My last multi processor design was in the 1990's using MC68HC11 chips and I used SPI. Here SPI, I2C, and standard serial ports are all viable...
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    Which version of Teensy for a DIY synthesizer?

    I have built a few Teensy synths. The 4.0 and 4.1 boards have the most power, and are my first choice for anything that will be controlled over MIDI only. I have two MIDI only 6 voice poly synths running simultaneously in a T4.1 with a bit of power left over for the UI which is still a work in...
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    Big MIDI mixingconsole project

    I agree with what's been said. This box started out as one of those white breadboards and two pots. Then one encoder was added. Then I wired up the first perf board proto. It had an audio shield strapped on a Teensy, with 3 buttons and 3 pots. It was electrically identical to the board used in...
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    Teensy 4.0 I2S Support

    I'm not sure how much it helps but pictures of my test board are in post #115 of the Teensy 4.0 release thread. My board has sockets for the T4.0 and a T3.2 or T3.6. It is also dual footprint for the Teensy audio shield or Paul's CS42448 board. All 6 combinations work even though I forgot the...
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    Teensy 4.0 Release

    I built a Teensy audio playground breadboard that uses a T3.2, a T3.6, or a T4.0 and either a PJRC Audio Adaptor or Paul's CS42448 board. I used the 1.46 beta 5 code with the fix to the output I2S file. All 6 combinations of the board worked using the Guitar code to test the output functions...
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    Teensy 4.0 Release

    OK, I'm not so stupid after all, I just didn't dig deep enough into all the T4.0 stuff. In post #3913 of the Teensy 4.0 First Beta Test thread user El Supremo has the answer. I applied his fix and the compiler builds code which runs on a T3.2. The compiler gives warnings related to audio clock...
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    Teensy 4.0 Release

    The three T4.0 boards I ordered arrived this morning. This is almost exactly 48 hours from ordering online to boards in the mailbox in "end of the dirt road West Virginia." Excellent service by PJRC, and a stroke of luck with the USPS since they quoted a Saturday delivery. Unfortunately I...
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    Teensy 4.0 Release

    Yes, that thing. I have built two of them and have them working with a T3.4 and a T3.6. The end use will be in a music synthesizer that's part digital and part analog.
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    Teensy 4.0 Release

    I dropped everything and ordered three of them when I got the email from Kickstarter saying BUY NOW!!!! Server struggling? It's dilithium crystals must have melted if everybody got that email at the same time (about 10:30 EST). I couldn't even open the PJRC home page for several minutes, and...
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    Quad channel output on Teensy 3.6

    Sure. The CS42448 board is the output for 6 audio channels created in the audio library. I have had good luck with the digital oscillators that I have been using. They are 1V/oct or MIDI controlled. Trying to make 6 notes of polyphony with three oscillators per note needs 18 VCO's. You can not...
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    Quad channel output on Teensy 3.6

    I bought three of these boards back when they came available. After sleeping on the shelf for nearly a couple of years, I grabbed one and set out to do my first SMD build in about 5 years. I can solder up a vacuum tube amp board in about 3 hours, but I designed it so I know where all the parts...
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    interfacing to an ableton push 2 controller with teensy 3.6?

    The original Push and the new Push 2 are both specifically designed to work with the Ableton Live DAW. Out of the box they will not even work on a PC and a different DAW. I know that there is a 3rd party hack to convert the original Push into a generic MIDI controller, but I am not aware of a...
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    "Screaming" low pass filter / Clipping issue?

    This is an issue inherent in the filter's design and has been discussed before: The only answer is to limit the controls to the filter element as to not go into the unstable zone.
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    where to find good 10k pots for a teensy midi controller

    I used these 858-P0915NEC15BR10K from Mouser in my two synth breadboards. The big one uses 8 to 1 multiplexing so that I can connect 49 pots to a T3.2 (now upgraded to a T3.6). The pots are used for controlling everything EXCEPT absolute pitch (VCO frequency). I use ALPS rotary encoders for...
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    Suggestions for pcb design in Linux?

    WMXZ, thanks for the info. I downloaded DS two days ago and haven't had time to dig into it yet. The version I got was PCB 8.0. What was different about the DS7 business model, it's a free tool. If I need to see a commercial message or two at startup, it won't bother me. My email tool makes me...
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    Suggestions for pcb design in Linux?

    I'm an equal opportunity amp builder. I started out tinkering with tubes in the 60's. You could get tubes and parts then for free, just by taking apart discarded TV's, radios, and HiFi sets. Over the years I have build more class AB transistor amps than anything else, silicon was free (samples)...
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    Suggestions for pcb design in Linux?

    luni, thanks for the input. I checked the Cadsoftusa / Autodesk web site hoping that I could use their "Eagle standard" version. It has a 160 cm2 total area restriction. The smallest board I make is 5 X 5 inches, or 169 cm2. Most of my boards are 250 to 400 cm2 which would require Eagle premium...
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    Suggestions for pcb design in Linux?

    I have been a loyal user of Eagle since DOS version 2.6 (around 1993). I have upgraded each year or so until version 5.11 which is what I an using today. Most of my PCB designs are for vacuum tube electronics, primarily amplifiers. These PCB's are usually rather simple 2 layer designs with 0.050...
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    Custom Midi Controller

    I haven't seen anything like those, but I tend to look for low $$$ options since I'm rather budget constrained right now and my synth currently has 53 knobs on it, with more in the works. The pots are the most expensive thing in the synth followed closely by the knobs. I am building a modular...
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    Custom Midi Controller

    I got my RGB LED encoders from Sparkfun. They have a small clear plastic knob that goes with it. They are not bright enough to see outdoors but work good in a dimly lit room. Mouser has these, but at $6 each, I haven't tried them...
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    Portamento- Teensy (3.1) Audio Sheild

    Portamento can be done two ways. Portamento first appeared in the Voltage Controlled synths of the late 60's / early 70's. The synths of the day (MiniMoog, ARP Odyssey....) were monophonic lead instruments where the keyboard generated a Control Voltage (CV) that changed the pitch of one or...
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    Multichannel USB audio with Teensy 3.6?

    You can stack two audio adapters on a single Teensy for 4 audio inputs at 16 / 44 and 4 audio outputs at 16 / 44. That gives you your 4 in 4 out. I have not tried it yet though, nor have I spent much time with USB audio, but the bandwidth is sufficient so it is possible.
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    LFO using waveform object

    OK, the Big Dumb Blonde One wasn't going to give up without at least blowing up some parts.......That usually only happens when I turn on the big power supplies and play with vacuum tubes, but that's a different forum. I dragged out my Teensy 3.2 breadboard from last May. It has a T3.2, an...
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    LFO using waveform object

    I tried that, then added also. It breaks more than it fixes since it was built from an earlier version. Arbitrary and reverse sawtooth waveforms are not supported, so I commented their use out of my synth, but still got lots of compiler errors. My attempts at messing with the...
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    Loud white noise on the edge of filter

    I have the same issue in my synth. It's one of those nagging loose ends that I have not even had the time to look for yet. Filter freq knob too far to the right AND resonance knob too far to the left makes a loud hissing noise. Fortunately those are not normal operating conditions, and they can...
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    +3.3v Line Shorted to GND

    I don't know what caused the fried boards, but I see one common element here that can blow low voltage CMOS parts like the processor chip. These parts are rated for somewhere between 3 and 6 volts MAX. Most digital ohm meters use a 9 volt battery. Their leads can put out up to 9 volts when used...
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    Eurorackmodular Teensy/Arduino Sequencer?

    This shield is made to plug on top of a UNO. The Teensys are physically smaller than the UNO so the shield will not directly fit the Teensy. Some type of adapter, or maybe even straight wires would be needed to make the two mate up. If you need the 16 bit converters for audio purposes, then...
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    LFO using waveform object

    I explained my method of doing this here: It does require at least two outputs from the Teensy. If you are using a T3.2 without an audio adaptor, it still might be possible to...
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    Just noise with Teensy 3.6 and Audio Adaptor Board

    I had a similar problem with a T3.2 and an audio adaptor connected by wires that were about 3 inches long. It seems that there can be some clock skew and cross coupling in those wires, especially without a good low inductance ground between the two boards. This causes the clock and data to get...
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    Fritzing components for teensy 3.6

    There is also DesignSpark. Some people love it, some hate it. I have not tried it yet. I have been using the professional version of Eagle since the early 90's (DOS version 2.6). I needed the pro version because my simple 2 layer PC boards for vacuum tube amps are too big for any other version...
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    Rocker midi controller

    The Brain and the Brain Jr are PIC chip based devices that are already programmed for one specific function, MIDI controllers. They have a Windows based GUI application that sets up the function of each pin, and what MIDI code gets sent when it is activated. Digital inputs and outputs are...
  32. T

    Rocker midi controller

    That's one option, and one that I have used myself. It requires very little thinking, but you are limited to sending note on / off messages. Another "no think" method is to use a Brain Jr. From Livid. They make several different MIDI controllers that sell for $$$$ but have a whole section of...
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    Teensy Convolution SDR (Software Defined Radio)

    Any plans to do NBFM demodulation using 25 to 30 KHz channel spacing for VHF and UHF ham radio? If so I can design an RF front end for such use. I spent 41 years at Motorola designing two way radio stuff, and was "retired" a couple of years ago. George (KB4LRE)
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    Wiring Midi Input to T3.6

    The yellow wire is connected to the same pin on the optoisolator as the diode. Either the wire or the diode needs to be moved to the left one pin. I don't know which without looking up the circuit.
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    32 Channel Digital Mixing Desk

    Analog pots are easy. One analog pin and an analogRead statement. Encoders require two digital pins each, three if the encoder has a push button and you want to use it. A software library is needed to read the encoders. So on the surface the pots are the way to go. If you want to be able to do...
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    Teensy 3.6 diy board

    These are identical IC die (bare silicon) in two different packages. The packages involve two totally different processes likely designed and built in two different packaging houses. I worked for Motorola when the Freescale spin off happened. At that time we did some packaging in house, and used...
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    Crash when using analogRead on Teensy 3.6

    Yes, I feed the DAC the output of a waveform object. The DAC outputs an analog voltage through a pin on the Teensy which I use externally in some analog hardware. The output of this hardware does get applied back to an analog pin on the Teensy to modulate a VCO by changing the frequency number...
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    Crash when using analogRead on Teensy 3.6

    I am not directly writing to the DACs. I connected each DAC output to a waveform object using the GUI in the audio library to create analog output LFO's (low frequency oscillators) for use elsewhere in my synth. All DAC writing is controlled by the audio library. The audio library also sends the...
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    Crash when using analogRead on Teensy 3.6

    Does the DAC have similar restrictions? I am having weird things happen with the second DAC output while my full synth program is running. The main loop spends most of its time reading 48 pots, and 4 encoders. Breaking this down into small chunks at a time causes no unusual operation. I will...
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    Filter LFO issue

    The analog inputs are multiplexed through a switch matrix into two A/D converters. All of this takes place inside the chip. The converter will connect the selected input to an internal capacitor. The cap is charged for a short time, then disconnected and the charge is read by the converter. If...
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    Filter LFO issue

    It doesn't have to be lower, it just works better in my synth with an upper limit around 10Khz. The filter changes the sound by removing the harmonic energy above it's cutoff frequency. The VCO's have little harmonic energy above about 10KHz, so the filter has minimal effect above 10 KHz or so...
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    Filter LFO issue

    I have heard the filter hiss at me, but I never figured out what caused it. I had some scaling values wrong in the math that figures out things like freq and ADSR settings. All the funny sounds went away when I fixed the math. I wonder why you are using such a high frequency setting, 19 KHz...
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    Announcement thread for Teensydunio 1.31 seems to be missing

    I loaded up the "guitar" example with the output playing out the I2S port through the audio adapter. I set up two waveform objects to make the 150 Hz triangle and 200 Hz sine routed to the DACS outputs. All worked correctly, so there is obviously something broken in my synth hardware or...
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    Announcement thread for Teensydunio 1.31 seems to be missing

    A simple sketch with a pair of waveforms 200 Hz sine, 150 Hz triangle, each wired to one of the inputs to DACS and the same input on I2S works fine. I get the proper tone in the headphones (I2S) and see it on the scope (DACS). What's getting broken in my synth? Tomorrows challenge.
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    Announcement thread for Teensydunio 1.31 seems to be missing

    My synthesizer uses the audio shield for audio output. I have been using DAC0 for an LFO output. I replaced the two separate DAC instances with the new DACS object. The sketch compiles and runs. DAC0 now puts out LFO1 as it always did, but something strange comes out of DAC1. I have a waveform...
  46. T

    Announcement thread for Teensydunio 1.31 seems to be missing

    Attempting to simply add a second DAC compiles and uploads to a T3.6, but the sketch does not run in the target device. I will experiment further tonight.
  47. T

    Printing a wave amplitude to the code.

    Yes. DC object set to an amplitude of 1 goes into envelope, then envelope goes into filter frequency mod in. I also have a mixer object between the envelope and the filter so control the sweep range. Other inputs for the mixer are a sine object (the LFO) and an A/D (Analog read pin) for a pedal...
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    Guidance on Midi Board - 64 rotary encoder > usb midi > Abeton using Teensy 3.2

    I don't know if you have encoders yet, but these guys are on sale again. They work well with the T3.2 and T3.6 using the built in encoder library. Ground the middle pin, connect each outer pin to the Teensy digital pin with a 1000 pF cap to ground. I haven't tried any multiplexing schemes yet...
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    Can Teensy 3.6 replace [Quad-Audio + Teensy 3.2]?

    It may be possible to do what you ask, but there are some stumbling blocks you need to understand. Depending on the audio quality that you are looking for the internal D/A's and A/D's may not be good enough. The Audio shield runs at 16 bit resolution and a 44.1 KHz sampling rate, same as a...
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    Stereo Audio Recorder

    You can record audio from the on chip A/D but you will not get 16 bit quality. You get more like 12 to 14 bits depending on how you interface it and how it is multiplexed. Best results come when driving the pin from a low impedance source. There are two A/D converters inside the chip which are...