For more Details have [a look at the Repo](https://code.hfbk.net/t6/sdiy/wikis/th-vco1)
**NB: All rights to the basic schematic design rest with Thomas Henry. We do not claim or grant any copyright or license to this design. His policy is to only distribute printed PCB boards via fonik. He granted us a one time chance to sell our run.**
The VCO-1 is a triangle core VCO designed by Thomas Henry. Thomas Henry made the original ±15V available on [birthofasynth.com](http://www.birthofasynth.com/Thomas_Henry/Pages/VCO-1.html). Because Eurorack Modules use a supply voltage of ±12V and the CA3080 OTA is harder to get, [Tom Whitwell](https://github.com/TomWhitwell/TH-VCO1) from [Music Thing Modular](http://musicthing.co.uk/modular/) made an Adaption for Eurorack. This is our fork of Tom's design, with improved routing, added voltage reference and a completely new panel.
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The VCO-1 is a triangle core [VCO](https://code.hfbk.net/t6/sdiy/wikis/vco) designed by Thomas Henry. Thomas Henry made the original ±15V available on [birthofasynth.com](http://www.birthofasynth.com/Thomas_Henry/Pages/VCO-1.html). Because Eurorack Modules use a supply voltage of ±12V and the CA3080 OTA is harder to get, [Tom Whitwell](https://github.com/TomWhitwell/TH-VCO1) from [Music Thing Modular](http://musicthing.co.uk/modular/) made an Adaption for Eurorack. This is our fork of Tom's design, with improved routing, added voltage reference and a completely new panel.
In the 2016/2017 Synthesizer Workshop at Computerei we decided to built the TH-VCO1 in Tom Whitwell's adaptation. We needed to order the PCBs ourselves which required a fresh export of Gerbers because our PCB manufacturer had different DRC rules than Tom's. However there were a few things that we wanted to change (including the panel layout). One thing lead to another and nearly every bit of Tom's original traces have been reroutet. This had to do mainly with the different requirements we had doing a workshop with students of which some never touched a soldering iron before and others didn't had much to do with synthesizers before. Other changes had been implemented on Tom's advice ("add a voltage reference") to make it a even more versatile VCO.
The triangular core of the VCO-1 is a Schmitt Trigger Integrator Circuit. If you're interested read more about it on [birthofasynth.com](http://www.birthofasynth.com/Thomas_Henry/Pages/VCO-1.html) or [here](https://code.hfbk.net/t6/th-vco1/wikis/core)
