Aguilar DB 680 Owners Manual

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Model DB 680
Tube Bass Preamp

Congratulations on purchasing Aguilar Amplification's DB 680 Tube Bass Preamp!

The DB 680 is designed and manufactured to provide the most discriminating bass player
with a studio and live performance tool worthy of a fine instrument. The DB 680
addresses the contemporary bass player’s needs in all studio and live applications, and is as
effective for recording as a chain of the most desirable classic studio gear.

The DB 680 has two fully parametric EQs, not semi-parametric, for complete tone
shaping possibilities, a tube driven resonance circuit, tube effects loop, and variable
balanced outputs. For the road, there’s a great sounding crossover, -40 pre and post-eq
outputs for the mixing console and footswitchable inputs and master mute (leaves tuner
input on for silent tuning). The chassis of the DB 680 is steel, and can withstand the
bumps and grinds of a tour.

Most importantly, the ten tube stages make for a sweet, warm tone and smooth feel
beyond compare!

All Aguilar products are hand made in NYC

www.aguilaramp.com

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Specifications:

All measurements taken with a line voltage of 120 VAC.
All voltages are RMS.
All noise measurements are unweighted.

Tube complement: Five total; two 12AX7A/7025 high-mu twin triodes
and three 12AU7 medium-mu twin triodes

Input Impedance: 1 M ohm (passive mode)
56 K ohm (active mode)

Output impedance: Normal output = 1K ohm.
Balanced output = 600 ohm
Crossover outputs = 75 ohm.

Signal to noise ratio: -80 db

Power requirement: 100-120-220-240 VAC/50-60 Hz.

Internally selectable. Refer to a qualified service
technician to change voltage selection.

Power consumption: (at 120 VAC): 0.75 A, 87.75 W

Rack size: 2 spaces

Weight: 17 lbs.

INPUTS:

Two Selectable Inputs:

There are two inputs on the front panel of the DB 680. There is an input selector switch
to the right of the inputs. You can switch manually between inputs one and two. The
center position (labeled F/S) is for footswitching, using the provided footswitch. This
feature allows you to keep two basses plugged in, and be able to switch easily and silently
between the two.

Active/Passive Switch:

This switch applies to both inputs. Nine times out of ten you’ll use the passive input. If
your bass’s output distorts the input section, switch to the active position. In the active
position, a 12db pad in the signal path will remedy the situation.

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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.