Overview of the UBZR1 Analog Synthesizer

Chelys Lyra

I have been interested in synthesizers since a very long time and I had do-it-yourself built two analog synthesizers. These were of the classical patch cable and "potentiometer control" type to define and control the sound.

This time I wanted to build a synthesizer that can store and re-call "patches" and settings while keeping a manual tactile feeling when operating. I named it UBZR1.

For UBZR1 I had the following design objectives:

Musical capability similar to the MiniMoog synthesizer
Fully analog sound generation
Save and restore of patches and settings
MIDI interface

The synthesizer has four main parts:

Analog sound generation
Keyboard
Digital to Analog Interface
Human User Interface with real knobs and switches

UBZR1 Architecture Overview

While MIDI is used for the "digital side" of things − for example to store and retrieve patches − there is yet no MIDI capability on the keyboard side. I.e. the keyboard is an analog device like with the classical analogue synthesizers. I intend to add MIDI on that side as well. Due to the modular design this is straight forward to do.

The description of UBZR1 on this web site is structured in the following sections:

Architecture: this section shows the sound generation and modulation components and the signal path
Mechanics: this section shows the case and mechanical construction
Modules show the various electronic components of UBZR1 that are mostly built as slide-in modules for a standard 3-unit height 19" width crate. The power supply is mounted to the back of the crate and the analog keyboard is a separate device in a wooden housing

Check out the sound clips to hear some examples what this piece can do.

Please also read the legal notices for this project.

Human User Interface (HUI)

I have the following requirements for a "real" HUI:

Real knobs. "Heavy" gear with good tactile feed back
Real switches
Settings displayed in an analog manner (e.g. bar graphs)
Arrangement of knobs, switches and display to follow the signal path on a panel as with vintage analog synthesizers
All knob and switch settings ‑ which means "patches" ‑ shall be able to be stored
Patches to be re-called and shown on the displays
Storage of the patches shall be achieved both:
- within the HUI device itself
- as MIDI SysEx files on some external file system based storage medium, usually a PC, Mac or other MIDI-capable device
No noticeable and annoying operating system overhead with boot process et cetera.

The GHTL1 device is my solution to these requirements.