Video: Breadboarding the MFOS VCO

VCO breadboard part 2

OK, gonna write this complicated stuff up maybe more for my own benefit than anything else, but your thoughts welcome. What happens in the pulse output is the ramp goes into an op amp wired as a comparator and makes a pulse wave whose width depends on the reference voltage you set on the pulse […]

VCO breadboard

I’ve lately been breadboarding new modules before building them, even ones based on designs and PCBs developed by others which presumably have been debugged already. Reasons? One is I think breadboarding helps in understanding the circuit design. Another is testing modifications: Obviously if I have in mind making substantive changes to the design I’m going […]

Lots of noise

My next few Kosmodrome modules will be ones based on Music From Outer Space designs, because the boards are available from SynthCube and SynthCube had a 20% off sale Thanksgiving weekend, so I bought them then. It’s been a long time since Thanksgiving, I’ve not been doing much building, but the first one’s done now. […]

Living in sync

A little while ago this LFO mod came to my attention: That caught my interest, since I’d just ordered a PCB for the Music from Outer Space Voltage Controlled LFO, which has a lot going for it, but not sync. Sync is useful if, for instance, you want to create a vibrato-like variation in pitch […]

Modules from Outer Space

Three days, three packages. Wednesday, Tayda: Miscellaneous capacitors, resistors, diodes, transistors. Some panel pots and a bunch of trimmers. Ripple counters, TL07xs. Screws and spacers. Thursday — Thursday! Thanksgiving Day! USPS! I Know! — DigiKey: MIDI sockets, JFETs, resistor arrays, 7555s, DACs, pricey op amps, optoisolators, still more trimmers. Friday, SynthCube: Transistor arrays, tempco resistors, […]

Case two part two b: VCO

I’m now thinking about whether to change my plan for the (first) Kosmodrome VCO. What’s prompted this is Sam saying he’s going to consider a Mark 2 LMNC VCO. Sounds like it would address the output levels, add a sine output, maybe ditch the 3340 pulse wave in favor of creating one from the triangle […]

OBG VCF TLA OMG (part 4)

Capacitors in and new, corrected panel PCB installed; it’s done. New video up:

OBG VCF TLA OMG (part 3)

The VCF front panels from JLCPCB, my first PCB front panel order, arrived last week: What looks like white streaking in the black areas really is light reflecting off the not entirely smooth texture of the surface. It looks better in person. Not the highest quality panel ever made by any stretch of the imagination, […]

OBG VCF TLA OMG (part 2)

I got the VCF boards from PCBWay: Even though I ordered them two days earlier, I have not received the boards from JLCPCB: Sigh. Not that those boards matter, really; I don’t intend to use them. But then there are the panels also ordered from JLCPCB, shipped but at last report (five days ago) still […]