R-52 Vacuum Tube Multimode Filter
The R-52 uses two pentodes, type 12AU6. The circuit is derived directly from our award-winning TM-2 filter, but with all the features of our TM-6 filter. A pair of bandpass filters is swept with a Vactrol(tm) control element, a resonant treble filter and a less-resonant bass filter, giving a 4-pole lowpass response. Filter sweep range (approx): bass-only 80-200 Hz, bandpass/lowpass LOW setting 300-1000 Hz, HIGH setting 800-1900 Hz. Filter resonance/Q adjustable from less than 1 to oscillation. Voltage gain approx. 2 with RESONANCE set to 10 o'clock position and INPUT LEVEL set to maximum. Both filters, or one at a time, may be selected and mixed in desired amounts using the front-panel RESPONSE control. This allows for a wide range of equalization and special sound effects. CV inputs are available for sweeping the cutoff frequency and for affecting the treble filter's resonance. Circuit distortion is less than 0.5% typical.
Power requirement: +-12v dc, 150 mA.
The Metasonix R-series of vacuum-tube modules is intended for use in any "Eurorack" standard modular synthesizer system. All R-series modules are 22HP (112mm) wide and fit in any Doepfer(tm), Analogue Systems(tm), or other compatible cabinet. They are powered entirely from the cabinet's internal +-12v dc power supplies, using Doepfer compatible 16-pin power connectors. Their circuits protrude behind the panel less than 25mm (1 inch). All vacuum tubes are NOS (new old stock) types from classic American and European manufacturers that are run very conservatively for long life, and are readily available from distributors. The tubes protrude from the panel for visibility and cooling, less than 38mm (1.5 inches), and should fit inside a Doepfer A-100 suitcase cabinet lid or into a Doepfer mini case. All audio inputs and outputs and CV inputs/outputs are 100% compatible with other synthesizer modules. Plate voltage is provided by a tiny switching supply producing clean 48v regulated at low current, which is very safe and will not injure the user. Potentiometers are top-quality Alpha RK12L types, and 3.5mm phone jacks are special Kobiconn vertical-mount types, much better quality than the cheap ones usually seen in Euro modules. Each R-module is fully protected against reverse supply voltage, overvoltage, undervoltage, or incorrect hookup to external equipment. As with all our products, the R series is totally handcrafted in Northern California, USA.