The PCB and Panel have no known errors. The Rev 3 PCB is blue. Label Clarifications R27. This is at about 9 o’clock on the board. The label is partly obscured by misplaced “LED”D3. This is at 6 o’clock on the board. The label is AWOL: it just has the K. For the shrouded power …
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PCBs for Other Formats
Many of our Eurorack PCB can also be used for other systems. PCB-ONLY SALES Panels and parts not included. PCBs comply with ROHS requirements. Schematics (Eurorack operation) emailed on purchase. Most of our PCBs now allow an MOTM-style header and should operate with +/-15V. Most of our PCBs also have mounting holes (irregular locations.) The …
Blat: Theory of Operation
Blat is implemented with a transistor monostable multivibrator. This provides a pulse signal for the tonguing signal (through smoothing LPF), and an inverted output for the “blat” circuit (through ramp-forming HPF and smoothing LPF). Mix Out The Mix Out mixes a softened version of the pulse (“tongue”) with the BC/AT signal. The Amount knob determines …
Blat: the Backstory
A characteristic well-known to reed instrument players is that some instruments are “slow to speak”: the saxophone makes noise with even a small amount of wind pressure while the clarinet takes a litt;e more effort to get it to start. Players rapidly learn how to adjust the [ressure tp get the note to star but …
Blip! Release Notes: Rev 3 PCB
This is a blue lead-free (ROHS) board. On the back, it says “Rev 3”. There is one known issues with the PCB. The decoupling capacitors C6, C7, C21, C22 are connected to each other but not ground. These will not be effective. Required fix: put in link (e.g. snipped resistor leg) between one of the …
Shell Release Notes: Rev 3 PCB
There are no known error issues with the board. The Rev 3 PCB is a blue ROHS-compliant PCB. Please note that C5, C7, C8, C9 are bi-polar capacitors (non-polarized-NP). You could substitute a suitable non-electrolytic at a pinch.The circuit does not depend on any exact capacitor values, so you can substitute neighbouring values. You can …
ProPulse: the Backstory
To understand the ProPulse, we need to understand the ARP Pro-Solist. Madness The ARP Pro-Soloist is a fascinating synthesizer: its facilities are totally over-engineered for the limited numbers of presets it provides. I have long been interested in its crazy circuits, and indeed posses a couple of circuit boards from one. It has been out …
ProPulse: Theory of Operation
The ProPulse Waveshaper Mixer takes a saw wave (or other) and generates a variable pulse wave out, where the pulse is delayed by about the same amount as the width of the pulse. Thus as the pulse increases, it changes its phase compared to the input signal. The unit provides a single active control: “Fraction” …
Vox H. : the Backstory
In the early 1970s, resonators were all the go. The grandaddy was the ARP ProSoloist with its complex banks, but the Polymoogs gave it a run for the crown of most preset resonators. And the jewel in the crown for the Polymoog resonators was the Vox Humana resonator, which came with the Polymoog Keyboard product. …
ProPulse Release Notes: Rev 0 PCB
Note the following: The board has holes for both a large 7805 and a small 78L05. Do not install both: install one or the other. Capacitors C1, C3, C7 should be non-polarized or bipolar capacitors.Please use a shrouded header for the Eurorack power connector. This will prevent you from attaching the power ribbon cable the …
Freak Out! 