In the classic Tangerine Dream albums of the 1970’, once can hear a distinct phaser sound that is usually placed over sequenced parts. Klause Schulze was also using this unique device circa the same time.
The phase was created by “Gert Schutle Audio Elektronik” and has created much of the Kraut rock sound of the 1970’.
In my previous post on the Roland Dim-D I has referred to do-it-yourself projects by Jurgen Haible who had also decided to clone this great phaser.
Well, needless to say, I immediately jumped on the wagon and ordered myself a PCB with the required 8 Light Depending Resistors (LDR) that form the base of the effect.
While working on building and debugging the module I learned a good lessons; always check the parts you receive from suppliers. In my case, the resistors I ordered were substituted with another resistor value so instead of getting a 2.43K Ohm I got 243K Ohm, which made all the difference between a dead device to a working phaser...
After selling my two Blacet VCOs, I went on to built three CGS VCOs from the PCBs, ordering them from Ken Stone at CGS web site, a great person to do business with!
Well, I soon found out my setups usually involved connecting two VCOs together to fatten up the sound, which is a pain as a patch that consists of two VCOs costs me 2 modules and 4 spaces in my rack, let alone the dedicated tuning per module that should take place each time.
Why not create a dual VCO module that is made up from two distinct VCO boards that are connected together?
Enter the “Power VCO”.
It is built from two CGS VCO boards, stuffed for all features (wave shaping and sub oscillator) and hooked together so that a single front panel can be used for two VCO modules.
I used dual gang potentiometers in order to control two boards with a single knob turn (apart from the fine tuning of each board naturally) and included small mixer board internally to sum up the inputs into a single out socket.