Tonic is a 3 band eq for 500 series. A simple but incredibly useful inductor based Class A equalizer for 500 Series racks.
Audio path qualities
As with the other 500 Series modules in this range, the Tonic signal path uses our True Class A BE41 amplifiers followed by a BE50 buffer to excite the Lundahl output transformer. The resulting sound is big and open with a nice touch of transformer color. The design allows for +26dB headroom so major boosts at low frequencies are not a problem with the Tonic - it always sounds huge!
Inductor-active filter blend
the Tonic utilizes real inductors (chokes) in the high and low bands whilst the sweepable mid band features an active filter based on the Constant Amplitude Phase Shift circuit proposed my Mr Steve Dove in 1981. The combination of the old passive circuits with a modern active design gives you the best of both worlds. The chokes in the bass and treble provide the smooth sound of real resonance in addition to the versatility of the sweep mid band.
If you wish to add some tone to your recordings, the Tonic is the perfect choice - it is excellent for applying broad eq strokes right across the audio spectrum. The versatile mid band can tame lower mid resonances or bring forward more presence in vocal recordings and the passive 18dB/oct high pass filter will effectively remove unwanted low frequency content. The Tonic is an excellent partner to our Elixir mic pre - add an Essence compressor and you have a complete Buzz Audio channel strip in your 500 series rack!
Controls and functions
The low band and high band have centre detent pots for +/-15dB of boost/cut range. Toggle switches select bell or shelf mode on these two bands. The low band turnover frequency can be selected to 60Hz or 120Hz and the high band 5kHz or 11kHz.
The mid band frequency can cover the range of 75Hz to 11.5kHz via the x1/x10 range switch. Another switch selects wide or narrow bandwidth (Q), and a centre detent pot sets the mid band +/-15db boost/cut range.
Additional toggles are provided to Bypass the module and to switch in the High Pass Filter. The high pass filter turnover frequency can be set by the user to 85Hz or 50Hz via jumpers on the circuit board. A Peak led lights up when the output level reaches +22dBu.
Maximum Input Level; +23dBu
Maximum Output Level; +26dBu into 3k ohm load
Frequency Response EQ set flat; 17Hz to 175kHz (+1dB, -3dB)
Harmonic Distortion measured: +10dBu output level; 0.08% @ 100Hz, 0.02% @ 1kHz, 0.005% @ 10kHz
Signal to Noise Ratio; -88dB A wtg, input shorted
Input Impedance; 20k ohms approx balanced
Indicators; Single LED overload indicator
Size; (37Wx132H). Fits 1 space in API* 500 series rack format
Power requirements; 120mA +/- 15-18 volts DC, as supplied by frame power supply.