I was able to throw together a 3 row 84hp wooden rack after some Youtube videos about box joints and purchasing a dado saw blade. The fleet looks much more impressive in a rack rather than spread out across my desk.
This rack is intended for a future project, but can conveniently hold this one for now!
Currently each module is either untested or “not working” and needing troubleshooting, except for two. Each ‘unready’ module is currently mounted upside down to indicate its unusable state. Hopefully some of these will get flipped soon as a couple remaining parts come in and I begin troubleshooting modules one by one.
I have plugged in any modules that have their wiring completed to at least try to use them in their initial states, and have attempted to calibrate them where appropriate. In most cases, not much appeared to happen, with audio refusing to come out of the modules. In a couple cases with some of the dual-purpose modules, clearly one part is working fine while the other is not. In the worst cases, something clearly burned out as soon as the module was connected to power, producing a pop and an infernal stench.
The module-by-module breakdown:
The VCO’s
These are the most complex modules, so its no major surprise that they didn’t work ‘out of the box’. One (VCO 1, I believe) clearly burned out a cap or more when I plugged it in, with a audible pop and odorous results. I believe it was the red film cap on the lower board, but was not positive. The other 2 VCO’s performed less spectacularly by simply not producing sound, although one (VCO 2, I believe) seemed to produce a great deal of heat on one of the IC’s.
Noise Source/Ring Mod
The noise source portion of this module is working great, although it still needs to be calibrated. The ring mod portion of the module doesn’t seem to output any audio when fed two input audio signals, and attempts to calibrate it according to the somewhat confusing calibration instructions have not succeeded or altered this result. I’ve taken several rounds at troubleshooting the PCB, and was able to find and replace a couple incorrect components, but this did not change the result of tests of the ring mod, and I had Anna double-check the components for me after checking them myself about 5 times, so I feel confident that the components are correctly installed. I am currently waiting for support on this module from Pharmasonic, but my priority for troubleshooting has shifted from this module to the Amp/EF/Integrator.
Sample & Hold
This module is waiting for the arrival of some 3-pin connectors that I intend to use for connecting panel-mounted pots and switches to the PCB’s when appropriate.
The VCA’s
Initial tests resulted in hugely distorted audio coming out of the amps when fed with an input source. Pharmasonic has assured me they probably just need to be calibrated correctly, and has provided extensive instructions on that process, but it requires a +10V CV, which I’m unable to create with my current setup. The 2hp MIDI module is capable of only +-5V signals, so it cannot supply this high of a voltage. To this end, I’ve ordered a Mutable Instruments Shades module, which should be able to provide a constant +10V signal, which will allow me to move forward with attempting to calibrate these modules. Alternately, if I can get the Amp/EF/Integrator module working, I think I can use the amplifier component of this module to boost the +5V signal from the 2hp MIDI module to +10V. (Update: Pharmasonic has explained that the amp is not intended for use with CV, and that doing so could damage it, so I won’t be using the amp to create test voltages with.)
The VCF’s
These are also some of the more complex modules, so there was some relief when nothing seemed to burn out on initial powerup of these modules. The Lowpass didn’t output any audio, while the Multimode filter outputted crappy sound audio while in lowpass and bandpass modes, and didn’t output anything in highpass mode in initial power-on tests. I have not tried calibrating these modules yet.
The LFO’s
These are not complete yet, as they need to have their rotary switches wired up to the boards. I need to do some research on how to best do this wiring, although I do have a good technical layout for the process.
The ADSR
This is waiting on an illuminated push-button switch to complete, which is on order from Thonk.
The Amp/EF/Integrator
The amp portion of this module doesn’t output any audio. The EF hasn’t seemed to produce an output CV when audio was fed into it in an initial test. Additionally, the EF’s green LED remains constantly lit when power is supplied to the module. The Integrator portion of this module seems to work great in initial tests.
The Phase Shifter
This module is waiting on a shipment of special IC’s that was missed in the previous rounds of component orders.
The Multi
This is working great and has already proven very useful in my test rack.
The Mixer
This is working great and has also been very handy in the test rack.
The Plan From Here
Obviously, there is still a lot of troubleshooting, wiring, testing, and calibration before I can consider this project complete. Also, my intention is to ultimately house this in a 2-row, 104hp rack instead of the current one, as that would be more in line with the original Block 1 design.
I need to take a pass at wiring the LFO’s, which means figuring out what is needed to gracefully attach a large number of wires to a board such as this.
I need to get the 3-pin connectors so I can connect any 16mm pots used in the project, which will allow me to complete the S&H and move the ADSR closer to completion.
I hope to work with Pharmasonic to get support to troubleshoot the Amp/EF/Integrator module first, and then use that as a tool to calibrate the other modules that require a +10V CV to do so. (Update: Pharmasonic has explained that this amp is not for CV usage, so this is not possible. This also means that troubleshooting this module is now no more of a priority than troubleshooting any of the others. I plan to continue to troubleshoot this module first, though, as it is a fairly simple circuit and Pharmasonic has already begun providing email support for it.)
