R-52 Multi-Mode Filter

The R-52 uses two pentodes, type 12AW6. 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 SOURCE: The R-52 should be connected to a power supply ONLY of the type described in the operating manual or as marked on the R-52. It uses +12v and -12v at 150 mA, and draws about 400 mA when first powered on (dropping to 150 mA after a few seconds). The power input is a standard Doepfer (tm) 16-pin IDC type, with the -12v pins on the BOTTOM. The pins above the +12v pin row are not used and not connected.