3
Input Gain Control:
This pot controls the gain of the preamp section. Clean sounds are usually achieved by
setting the input gain around 11 or 12 o’clock. A little bit of musical distortion will occur
if set past one or two o’clock.
Dual Parametric Equalization:
There are two serially arranged active networks, +/-12db. One EQ is set up from 180 Hz,
(low mids), fully variable to 1.2K, (high mids), with fully adjustable bandwidth (Q), and
level controls. The other EQ is set up to be fully variable from 1.3K to 7.5K, (highs),
again with fully variable bandwidth and level (boost and cut). This is the most flexible
arrangement for bass.
What’s so great about
fully parametric
equalization?
Pleasant sounding equalization tends to be broad bandwidth. This means that
you’re boosting not only the selected "center frequency", but specific surrounding
frequencies as well. This makes for a more "musical" effect than a "fixed" narrow
bandwidth equalization. So why have bandwidth control? Because many useful "cuts" are
narrow or relatively narrow. For example, if you think your bass sound is muddy, you
might want to decrease or cut 200 Hz, a frequency in the low-mids area. But you
probably don’t want to decrease the frequencies around 40 Hz, as that might make your
low end sound weak. Other bass preamps offer only "semi" or "quasi" parametric EQ.
These types of EQ are not as effective because they don’t allow you to "zoom in" as
precisely on the frequencies you wish to affect. The DB 680’s EQ section is as
sophisticated as the finest studio EQs available.
TUBE EQ:
Treble:
Tube driven shelving type, boosts up to 12db. The center frequency is set at
4 kHz.
Bass:
Tube driven shelving type, boosts up to 12db. The center frequency is set at 40 Hz.
Deep Switch:
The deep switch controls a tube driven RLC resonant EQ, fixed at 30 Hz. Two positions
are provided for flexibility. In the left setting (+) 30 Hz has a smaller amount of gain than
in the right setting (++). The (+) setting is great for "fattening up" a bass sound, while the
(++) setting adds loads of bottom.