What, where are the vacuum tubes?
Krautrock Phaser
Once again inspired by Hainbach, I decided to build my own "Krautrock Phaser". From the webpage: The background of the "Krautrock Phaser" in Jurgen's own words: "If you listen to German records from the 1970's, you often hear a rather unique phasing that comes from a device called "Compact A Phaser" from the Berlin company "Gert Schulte Audio Elektronik". It's often referred to as "Schulte Phaser", and I have heard it being called "Krautrock Phaser", "Schulze Phaser" (because it's prominent on many early KS albums), "TD Phaser" (because of Tangerine Dream). In my opinion, this phaser has been important to the sound of these early electronic musicians almost as much as the synthesizers they used."
It's basically a low-frequency oscillator that drives a couple incandescent bulbs surrounded by light-dependent resistors, which control the phase on banks of op-amps in the audio path.
The Univox Univibe that Jimi Hendrix used a lot is very similar. This one has a lot more options though.
What, where are the vacuum tubes?
Using a slope front metal case.
The board is mostly populated.
Starting to wire it into the case.
All wired in. Note the heat sinks on the power transistors, lower right corner of the board, more on those next.
I wasn't able to dissipate enough heat with the slope front box limiting room for heat sinks, so I remoted the transistors to the back panel, and they operated MUCH cooler.
There you go.
Here are the lights that modulate the resistance of the light-dependent resistors, in action.