I discovered that Calsynth offers populated PC boards for many ST Modular modules, which are all DIY. The cost for both populated PCBs plus the panel is only $59 plus shipping (free shipping on orders over $100). You have to supply the panel parts: pots, switches, jacks, knobs and LEDs. For Singer you also need to buy two capacitors. All the rest of the parts are SMD and already soldered. The PT2399 delay chip is included! You should put the chip in a socket.
I have a number of delays in Eurorack, but until now no PT2399. (I do have one in my Bugbrand rig.) The PT2399 is known for the ability to drive into long, very distorted delay times, while still having a pretty clean sound on shorter delays.
Singer has all the typical controls you expect on a delay module: Delay time, dry/wet mix, and feedback. There are knobs and CV inputs for all of these. Delay and feedback CV inputs have attenuators. You get control over the input level to the delay (just the delay, not the dry signal), by a knob and also a VCA.
The two inputs
Input is selected from one of the two inputs, A and B. Input B includes a high pass filter that attenuates frequencies below 320Hz. You have three ways of switching between the inputs: a manual switch, a gate input, and the internal LFO can also switch between A and B.
The LFO
The internal LFO has a manual rate control (yellow knob). There’s no CV of the LFO rate, but there is an LFO reset input. You can switch between a triangle or square wave LFO. The LFO is normalled to delay time and feedback CV input jacks. Override the LFO by patching to those jacks. The LFO rate LED indicates the LFO level after attenuation (this fooled me at first). The LFO is also normalled to the A/B input switch if the MAN / LFO switch is set to LFO. So you can control one or all of time, feedback, and A/B with the LFO. There is no output for the LFO by itself.
The Build
Singer is an easy DIY build. For the main board all you need to do is solder two capacitors, the power header, one IC socket and the three headers for joining the two PCBs.
For the panel PCB you solder pots, jacks, switches, and two LEDs.
There was one little hitch. A hole in each board is for a standoff to hold the boards together firmly. There was no standoff part listed in the BOM, but I expected simply to use the 11mm standoffs with m2.5 screws, which I had used for the previous DIY module. You can see a screw head next to the yellow LED in the top photo, and the screw threads protruding in the lower pic. Buy, yikes, the holes are too small for m2.5 screws. Not wanting to drill out the holes, possibly damaging the boards, I found some smaller screws that would still catch on the m2.5 standoff threads.
I had to guess the proper switches to order, which I got from Mouser, part number 612-200MSP1T2B1M2QE. There was no switch part number in the BOM. The BOM does not include knobs, so you have your choice. The nice large, aluminum black knob came from Synthcube. I used Davies 1900 Clone knobs with brass inserts, also from Synthcube. The yellow Davies knob is kinda big, next to the other two knobs. The Modular Grid page shows that pot having a Befaco miniature knob. I will try one.
Demo recording
The chord oscillator for this little demo comes from IO Instruments Himalia. I have a pulse generator triggering an envelope generator that controls a VCA. This is the input to Singer. The pulse generator is also resetting the Singer LFO, so it’s in time with the envelope.
It starts with just the dry signal. Then I bring the wet delay into the mix and operate the large knob, manually changing the delay time and going into extreme distortion. You’ll notice pitch changes while moving the knob and also when the LFO is modulating the delay time. The LFO modulation level is raised. Then, after a bit, the LFO is turned off and feedback is turned up. The delay time is made longer and the LFO brought back in, along with the feedback. Then, mercifully, the pitch of the Himalia oscillator is lowered and I twiddle knobs.
