I'm in the UK. Acrylic panels supplied by www.razorlab.co.uk. 3D side cheeks and the 4 mounting bushes from https://midlands3d.com/ . Both companies produced excellent components from the design files. I did have 2 problems with my first Teensy 4.1. The first was my fault - I left too big a gap between the cpu board and the audio card - this resulted in the assembly being too tall to fit in the case. The 2nd problem was with soldering the USB client wires to the underside of the Teensy. The solder pads are so small that when I bent the wire back to fit on the main PCB, one of the pads pulled off the Teensy completely with no way to repair. Fortunately, the USB client could still be accessed via the micro usb connector on the Teensy board itself. As a result of the above problems, I built a 2nd Teensy/Audio card combo being careful to keep the 2 of them sandwiched close together but ensuring no components touched each other. This time, when I soldered the data lines onto the bottom of the Teensy, I added a blob of superglue to reinforce the fixing. The only other point of note during the build was in adding a 100 ohm resistor into the SCK line to reduce the background noise at high volumes that some have commented on. I cut the track on the main PC with a craft knife and the soldered the resistor directly from the back of the Teensy to the solder pads of the display - worked a dream.
How does it sound -fantastic! Really deep base and crystal clear highs. Some very nice sounds amongst the factory supplied patches. I'm not much of a sound programmer and am looking forward to the user community making more available. One development to the firmware that would be very useful is a mode to put the unit into USB Mass Storage mode (ala PreefFM2) to enable patch files to be backed up and added from a host computer. Recommended - go and get one!
It took several sources to piece together the complete bill of materials to assemble this synth (e.g., PCB from Tindie, front panel from JLCPBC, acrylic case from Ponoko, Teensy boards from PJRC, various parts from Mouser and EBay, plus several self 3D Printed components, etc.). However once I had everything in hand, the build itself was quick and easy, by current DIY standards. If you've ever tried to build a MIDIBox, Ambika or x0xb0x synth, you'll find this much easier.
Now that my build is complete, I'm having a blast jamming with this synth using either Ableton live, Reason or Logic to sequence patterns, rhythms and melodies. The polyphony is great, because you can play complex chords, or even multiple tracks that use different presets.
I also love the fact that I can dig through the code in my Arduino IDE (Teensyduino actually), to learn how certain Synth features were developed and implemented.
I bought the bulk order - mainly because there was no shipping option to South Africa for the one-off synth, so I didn't get all the additional bits (display, 3d printed parts), but it was still pretty straight forward to get everything together. The Mouser bill of materials is a great start, although I found many of the parts out of stock and I spent a little time hunting down alternatives (of which there are plenty). Soldering is a little more than basic, with some of the through pins requiring a little care, but not at all difficult. The instructions are clear and step by step. I 3d printed my own display mounting from the files - the threads didn't come out well, but it works fine anyway. The only place I went wrong was not checking that the display I got had the backlight enabled by default - it wasn't, and the jumper to do it is on the bottom, so I had to add a wire between the backlight pin and 3V3, not a major problem, but do check before you solder it in if you want the neatest build.
I am running the synth without an enclosure while I wait for local industry to start up again in the new year to have that manufactured. It works out of the box with my USB midi keyboard and with Ableton Live.
The communications around ordering was excellent and the seller is very responsive and helpful.
I had a great experience so far and I only just got started. I highly recommend the TSynth - whether in bulk or single order.
Took 8 days to arrive. The boards are good quality with well soldered SMD parts. Well packaged and delivered directly from fabricator. Looing forward to building them.
Would be nice to have the option to use EuroPacket delivery from the fabricator. It only takes a couple of extra days to the UK and you prepay the taxes. Works out a bit cheaper as you don't have to pay the DHL handling fee, just the taxes.
Nov. 5, 2020
Electrotechnique First of all! The polysynth is excellent!
Hello Electrotechnique First of all! The polysynth is excellent. The circuit board and front panel are very good quality. The design and layout of the control elements is clear. The sound quality is very good, the USB connection is annoying with a high "crackling" sound. The menu navigation is good, own patches are possible. I can only warmly recommend the synth and the price-performance ratio is 5 stars !!!!
Some suggestions for the future: 1. Choices when ordering between red and black panels and ordering with / without front panel. 2. Eurorack compatible, slim PCB and front panel (128mm height) 3. a dimensional drawing of the holes and OLED cut-out for all DIYs who want to design their own front panel. 4. two pogo pins about 12.5mm instead of the cable for the USB host interface D + D-, I made it, works fine.
Many thanks for the great product! Greetings Thomas Effendy from Germany email@example.com
Note the part number for the pots is not correct on the Mouser BOM. These call for a shaft length of 15mm, however Bourne measures them from the base. This netted me 2 orders of 40+ pots that had a total shaft length of 6mm when measured from the base.
June 9, 2020
Exactly the kind of Teensy-based synth project I wanted!
I just finished my TSynth build and I must say this little synth is amazing! The build process was not difficult, but it may be more than a first time builder can handle. Parts and soldering took me about 2 hours and the mechanical build less than 1 hour. I had already made the sides, end cheeks and mounts ahead of time so it was only a matter of fitting them together and screwing them in place. Uploading the default firmware took just a few minutes and then my TSynth was ready to make music. The operation of the synth is very simple with so many knobs to play with. Navigating the menu and saving sounds is a walk in the park. The synth has amazing fatness that you would normally only find in true analog synths. I was amazed at its deep lows. The Teensy and Audio Library do have some sound artifacts and occasional noise, but I think these can be used as strengths when making cool sounds. The preset patches included with the source code are awesome! If these were the only sounds TSynth was capable of it would still be worth every penny. Fortunately this synth can do much more than the included sounds so it will be a fun journey creating new sounds to use with my music. I really am glad I was one of the very first customers to be able to enjoy this great piece of kit. It will fit in nicely with my other gear and I can't wait to feature TSynth in a song. Great work ElectroTechnique!
One thing to note on possible modifications for other customers. I think I will be modifying the bottom panel to include a door or access panel to allow me to get at the Teensy and the SD card. This will make is easier to backup or exchange the SD card in the event of data loss. I did have to pull out the card a couple of times during initial testing and it would have been a pain to do it after the case was fully on. I will probably cut an opening in the bottom panel and make a plate to cover it using magnets to hold it in place. This will allow me to access the card and the Teensy stack in case I need to. I will probably also add some 1/4 inch Line Out jacks to supplement the headphone output and make it audio mixer friendly. I might find some other mods as I play with it more. Once I have the hardware all to my liking, I will see what I can expand on in the software to give TSynth even more awesomeness!
I was lucky enough to be one of the first customers of the TSynth. I had been planning on building a Teensy-based synth project of my own, but when I saw the TSynth, I decided to see what I could do with this project instead. I received the boards last week (customs kept it too long). All the remaining parts have come in except for a sheet of 3mm acrylic to laser cut the panels from. I made all the 3D parts ahead of time and was happy that the fit with the boards was perfect. I plan to begin the build on the upcoming weekend so I won't have any real feedback about the build, operation and software till then. I can hardly wait!
On the subject of providing feedback, I would like to bring up a few things that are more about helping other makers (and the creator of TSynth) when it comes to the bill of materials and part sourcing. Unfortunately for me I do not live in an area with local parts suppliers so I had to order everything online unless I had it already. Some issues I ran into on obtaining parts were the PCB mount potentiometers and oddly the LEDs. The pots were difficult to find outside of Digikey or Mouser (I have my reasons for not going with them). I was able to find them at Jameco, but I had to settle for something other than Bourns or Alps. Something the documentation does not say about the pots is what type of resistance taper you need. I had to assume linear taper was the right choice though audio (logarithmic) taper pots were easier find in this package style. I guess I will find out if my gamble was correct or I will be modifying the code to compensate for the taper difference if I got it wrong. On to the LEDs. Believe it or not, I had too much trouble sourcing the low current draw LEDs. The documentation says get 1-2mA LEDs. I figured that would be no problem until I could not find anyone carrying anything with less draw than 10mA. The closest LEDs I could find were some vintage-esque Dialight PCB mount indicator LEDs that were outrageously priced. I resorted going through my LED bin only to be frustrated with all the high current draw LEDs in my collection. Out of shear luck I stumbled upon an old Christmas tree ornament kit in my project bins that was never built. The package said the operating current for the ornament was 8mA so I figured it contained 1-2mA draw LEDs. A quick test proved it did. Rejoice! I can move on now, but I think I will make some mods on the later Teensy 4.1 version of the TSynth if it still requires low current LEDs so I can use more common brighter LEDs instead. The only other bill of material things I can think of that may cause some headaches are the knobs and 5-pin DIN MIDI jacks. So many knobs are "D" shaft and my pots are knurled shaft. Got to match them to make sure it fits! The 5-pin DIN MIDI jack also must match the pin arrangement of the PCB, but the creator does note this in the documentation.
All-in-all I think I came in around $120 for the parts and board cost so the creator is close enough in his cost estimate of the build. I did have the display already but I am yet to determine if I have the correct one as noted in the documentation. If not I have two others on order or will make the software changes needed to fix things. I really enjoyed the demo video of the TSynth and this bad boy will compliment my collection of vintage and modern synths nicely I think. I can't wait till I can make some awesome new sounds from a Teensy! I'm going to build a Teensy-based multiFX unit but I wouldn't mind if you beat me to that project as well! (hint, hint)
Well thanks for the great work here. I will be back with a review of the build and the operation once I get it all up and running. Cheers!
Response from ElectroTechnique | June 10, 2020
Hello, thanks for the review. I'll start to update the Build Guide as reports come in. You can just email me at firstname.lastname@example.org with any questions! The pots are linear and if a log response is ever needed for a microcontroller, you would just code it. I buy the pots from AliExpress and these take a 2-3 weeks (pay for tracked postage). I intended TSynth to be low cost and deliberately bought the cheapest I could find. I've had no problems with AliExpress. Most components I've ordered from there, it's just one of waiting longer. Things like brass hex PCB standoffs are considerably cheaper as kits and also bulk knobs. The Mouser BOM deliberately omits these, as I was shocked by the price. Low current LEDs should be easy to find and a search for 'low current led' should be enough. They usually just need 2mA. With all four LEDs lit, TSynth draws a total of 180mA and can run all day from a power bank. I'm going to include the IPS display in future sales as I'm concerned that people will buy Adafruit or something else and find it doesn't work.
I received my order exactly two weeks from when I placed it, which isn't bad from S. Korea to New Hampshire, USA. The boards and front panel were well packed in bubble wrap to avoid any handling damage. The quality of the circuit board looks great and the pre-mounted parts appear to be soldered correctly. The front panel is well made and looks great. Unfortunately I can't comment yet on the functionality. I've ordered all the parts needed, but they are taking some time to arrive. As far as documentation, the only thing I would improve is to consolidate all the parts - electrical and mechanical - onto the Excel spreadsheet on Github. Right now only the electrical parts that can be purchased from Mouser are shown on the spreadsheet. To see all the parts needed, you have to go through the build guide document. Still, I'm very happy with the quality of everything. I'll update (if Tindie allows for that) once I have received all the parts and built it.