YuSynth Dual Pulse Delay Module Bare PCB

(£14.72 UK, incl VAT)
In stock

YuSynth Dual Pulse Delay


A bare double sided PCB (no need for the wire jumper links shown on the PCB layout) for the Yusynth Dual Pulse Delay synth module. These PCBs are manufactured by Soundtronics with a percentage of the sale going to the creator of the YuSynth - Yves Usson. These are early days for the YuSynth Modular Synth at Soundtronics, our plan is to stock PCBs for all of the projects as well as components, kits and front panels. This is going to take time but will eventually be as comprehensive as our MFOS range.

No components are included with the PCB but check out our Synth Components section where you should find what you need. We do suggest visiting the YuSynth Dual Pulse Delay project page for detailed information including Yves panel layouts but a summary is shown below.


Sorry but there is small error on the PCB. C2 is shown on the silk screen the wrong way around. It should be:



This module has two separate units that can be triggered either by one single GATE signal or by two separate GATE signals.

Each unit provides one output signal :
a delayed PULSE signal (0-10V) with a delay that can be set between 1ms and 1s;
and a pulse width that can be set between 1ms and 1s

The PCB can accept a choice of three types of power connector, it can be either a Synthesizers.com 6 pins MTA connector, a MOTM 4 pins MTA96 connector or a 10-pin Eurorack connector.


Click on the schematic thumbnail above for the circuit diagram.

The principle of this circuit is quite simple and rely on the use of a dual monostable CD4538 IC.
Here is how it operates : when a GATE signal (between 3V and 15V), the capacitor C5 acts as a differenciator and converts the gate signal into a brief positive pulse (width 10 ms). D1 protects the circuit from negative voltages. The brief pulse created on the rising edge of the GATE signal make Q1 briefly conductive and the voltage at its collector falls down to 0.2V. The collector is connected to the falling edge trigger pin of U1a. This triggers the monostable U1a and its output Q goes to a high level and stays there for a duration set by the RC cell built around (R5+P1)C6, P1 is a 1M log potentiometer and the delay can be set between 1ms and 1s.  After this delay Q returns to the low level and  in turn triggers  the second monostable U1b whose output Q  goes to the high level and stays there for a duration set by the RC cell built around (R6+P2)C7, P2 is a 1M log potentiometer and the delay can be set between 1ms and 1s.  The output Q is connected to a voltage divider (R7,R8) that delivers the OUTPUT PULSE with a amplitude of 10V. The base of Q2 is connected to the Q output of U1b and drives the LD1 LED.


The wiring schematic image in the above thumbnails show the panel wiring to the pots and sockets etc.

Setting and Trimming

No setting up or trimming required

Parts List

The parts list below is direct from the YuSynth website.

The parts list excludes knobs although we have standardised on the Cliff KM20B but it does include 1/4" jack sockets. All parts are available individually (use the part number in the search box above) or as a components kit that excludes sockets and knobs.

Reference Value Part No. Qty
U1,U2 CD4538 7212-520 2
Q1,Q2,Q3,Q4 BC547C 7212-401 4
D1,D2,D3,D4 1N4148 7212-480 4
R1,R2 10 ohm 7163-007 2
R9,R16 1k 7163-051 2
R7,R14 4.7k 7163-067 2
R5,R6,R8,R12,R13,R15 10k 7163-075 6
R3,R4,R10,R11 22k 7163-083 4
R17,R18 100k 7163-099 2
C5,C9 10nF 7212-745 2
C3,C4,C8,C12 100nF 7212-749 4
C6,C7,C10,C11 1µF LCC polyester film 7212-724 4
C1,C2 22µF/25V electro. 7213-108 2
LD1,LD2 Panel Mount 7213-900 2
LD1,LD2 Red LED 7213-901 2
P1,P2,P3,P4 1M log potentiometer 7300-070 4
Jk1,Jk2,Jk3,Jk4 6.5 mm jack socket 7212-204 4

No FAQ found

This was my third Yusynth/Soundtronics project and, as with the others, it's a high quality PCB, great to work with and produces an excellent piece of Euro kit. There aren't many components so even for a rank beginner like myself it's pretty straightforward. A few things to perhaps look out for (which I didn't, so had to make revisions during panel assembly): the polarities of the gate connections on the board aren't made clear, and they're at right angles to those shown in the wiring diagram. I soldered one and, when it didn't work, soldered both the other way round. Also, the second unit is normalled to the input of the first, so make sure to use use switched jacks. Thirdly, the LED current is pretty high and I added a 30k resistor to make them non-blinding - 2.2k is all I would expect to fit on an LED. You can fit all the works behind a 4 hp panel - it means a bit of fiddly work but you end up with a flexible, dynamic little unit in the minimum rack space. If I make another one I will add a bypass-through socket, to take the original trigger signal out along with the delays - not possible in 4 hp but you might want to consider it.

I built the Pulse Delay thinking it could be a gadgety thing to mess around with gate timings for rhythmic envelopes, but having got the unit up and running I discovered it does a lot more than just that. Apart from the obvious use of sending timed gates to envelopes and so on, the direct outputs can be used as glitchy envelopes, signals to chuck at oscillator linear FM, and plenty more. There's nothing better than a module you acquire to do one thing and then spent a lot of time exploring everything else you couldn't anticipate.

In all, a great piece of kit, and an easy build - top marks to Yves and Soundtronics for their great collaboration!
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