Hi Hadj,

The unit receives power directly from the USB connectors 5 V VBUS line. However, the current USB-C implementation does not include the required USB-C detection resistors on the CC1 and CC2 pins of the USB connector. Many USB-C power supplies, including Apple USB-C chargers and some multi-output USB-C power systems, will not activate their 5 V output unless they detect these resistors.

That would explain why two separate units show exactly the same behaviour. It also means that your power supplies and cables may be operating correctly.

Could you please try the following test?

• Use a conventional USB-A power supply or a computer USB-A port.

• Connect it using a USB-A-to-USB-C cable.

• Check whether it powers up as exepcetd
  

If the unit powers up with a USB-A-to-USB-C cable, the cause is confirmed. Thanks, Stefan

Stefan,

Thank you for the incredibly detailed reply. I will be checking all that out over the next day or 2. I took photos of my PCB, too, in case you notice any glaring issues, or if anyone else wants to see it. If necessary, I will also make a video of issues as I go through it.

One thing I noticed about the right serial sequencer is that the 4 gate outputs are always in sync, whereas the left side is obviously doing some sort of sequential thing.

I also find that even with the volume turned down on all knobs, it still outputs sound from both oscillators quietly.

Be well!

Quick update: moving the jitter calibrator provided noise at the noise output, but no change to the sequencer. I'll toy with it more and check those solder spots.

Julian

I'm not sure which mode is T&H vs S&H. But in both cases, the LEDs continue to flash at their internal rate, not at the rate set by the signal received at HOLD GATE when patched. In one mode, no signal is output at HOLD OUT regardless of whatever is patched at HOLD IN and HOLD GATE. In the other mode, the pulsating continues at the HOLD OUT regardless of whatelse is patched - the is mostly at zero except for the regular pulses.

Hi Angus,

thanks for the measurements.

The PT2399 pin 1 reading of 5V looks correct, so the 5V regulator is probably working. The first thing I would like to verify is the op amp power rails, because the values you listed look unusual.

The U3 reading is especially suspicious. Pin 8 should be a stable +12 V. If you get readings like 1.94 V or 21.16 V, please double-check the pin numbering, the orientation of the TL082, and whether the measurement was made against GND or against another pin.

Please also check the PT2399 reference voltage:

pin 1: +5 V

pin 2: about +2.5 V

pins 3 and 4: GND

If pin 2 is not around 2.5 V, the PT2399 or its surrounding parts may be faulty.

Please probe the signal at these points:

1. Input jack tip

2. U1 pin 1

3. MIX pot wiper

4. U1 pin 7

5. OUT jack tip after R15

If the level is already low at U1A pin 1, the problem is before or around the input stage.

If the level is good at U1B pin 7 but low at the output jack, check R15, the OUT jack, and possible shorts to ground.

If the dry signal is fine but the delayed signal is very low, please check the PT2399 and the parts around the PT2399 filter/output section.

Also, please make sure to use an original genuine PT2399 chip. Non-original or fake PT2399s are a common cause of low level, noise, unstable delay behavior, or strange modulation problems. If possible, swap in a known-good original PT2399 and test again.

Best,

Stefan

Dear Stefan, Thank you for your prompt and through reply. Switchign the jumpers did the trick. It appears that the original silkscreen label was correct? Long time time DIYer, but first time pedal user.....I still learing all of the ins and outs. At any rate, Everything now works flawlessly, sounds great. A solid addition to my kit. Thanks again!

Hey Jungle,

I’ve created the bottom solder paste Gerber and the board outline Gerber for you.

You can download the files here:

https://www.st-modular.de/file-share/fd10033e-7c78-4b36-8786-efb5183b9310

Let me know if it works for you.

Thanks,

Stefan

Hey again ,

is the right output silent for all 3 inputs?

If yes, I would first focus on the common right-output stage: U3, R105, C39, C1 and the OUT_R jack/solder joints. Also check the solder joints around pins 1, 2 and 3 of U3.

Thanks, Stefan

hey thanks for the very detailed reply, unfortunately I smoked the board, so I'll have to get a new one anyway :/

Hey Timm, thanks for your message, and sorry about the trouble. If the main L/R outputs work but the headphon output is completely silent, the issue is most likely around the U15 headphone section or the headphone jack/pot area.

Please check the soldering around U15, the headphone volume pot, the nearby capacitors/resistors, and the headphone jack itself. Also check if U15 gets the correct power:

• pin 4: +12 V

• pin 11: -12 V
  

Could you please send a few clear photos of both sides of the PCB around U15 and the headphone output area? I have also emailed you the schematics for further reference.

Thanks, Stefan