6990 Kingsbury Road | Templeton, CA 93465 | 805-461-4100 | http://www.demeteramps.com/
HBP-1 H Series Bass Preamplier User’s Guide
The H Series Bass Preamplier by James Demeter uses the same all tube front end found in his classic VTBP-201S Bass Preamplier and combines it with the revolutionary H Series circuitry found in his
professional audio H Series line. This preamplier provides the best of both the tube and solid state
world. It features high voltage (250V) tube front end (providing all of the preamplier gain and passive
tone controls), a two band solid state fully Parametric Equalizer that is tuned for bass, a fully adjustable
active eects loop with controls up front, a tuner output, a full balanced output with switchable microphone or line level, both a balanced TRS line level output and an unbalanced line level output for amplier connections, and a mute switch. As with all Demeter equipment it is meticulously hand wired, using
the nest components and assembled in the U.S.A.
CONTROLS AND FEATURES
INPUTS
Passive: is for passive basses or basses with lower output.
Active: is provided for basses with internal preampliers or basses with very high output.
TUBE PREAMPLIFIER
Volume: controls the output level for all outputs except the eects loop and tuner.
Treble: a passive 6 dB per octave shelving high frequency control. Boosts or cuts 10 dB. This control affects the 4 k to 20 k range.
Middle: a passive 6 dB per octave peaking mid frequency control. Boosts or cuts 10 dB. This control is
centered at 1 kHz.
Bass: a passive 6 dB per octave shelving low frequency control. Boosts or cuts 10 dB. This control affects the 120 Hz to 10 Hz range.
Presence: an active 6 dB per octave shelving upper mid to high frequency control. Boosts in the 1 k to
20 k range. The at setting for this control is the knob turned all the way to to the left.
PARAMETRIC EQ
EQ Switch: switches in or out of circuit the parametric EQ.
Boost/Cut: controls the boost and cut of the parametric EQ plus or minus 12 dB.
Frequency Controls: continuously variable frequency selection for each bandwidth (low frequency or
mid frequency). The number shows the center frequency.
Q or Width Control: controls how wide or narrow the aected frequency are. The most narrow setting is
one half octave and the widest is four octaves around the center frequency.
6990 Kingsbury Road | Templeton, CA 93465 | 805-461-4100 | http://www.demeteramps.com/
HBP-1 H Series Bass Preamplier User’s Guide
EFFECTS LOOP
Eects Loop Switch: this switch engages the the eects loop section of the preamplier activating the
jacks in the back and the controls in front. With nothing inserted in the jacks this switch will kill the
signal.
Send Control: controls level leaving the send jacks of the preamplier (the input jacks of your eect).
Return Control: controls the level returning to the preamplier from your eects unit into the bass preamplier.
Mute Switch: mutes all outputs except the tuner output.
REAR PANEL CONTROLS
Ground Lift Switch: This switch lifts the chassis ground from pin one of the XLR connector. This is used
when hum and noise are present in this connection.
Level Switch: This switch changes the output level of the XLR from line level (+4 dB) to microphone
(level -20 dB). The microphone level is used to input recording consoles microphone preampliers. The
line level is for line level and power amp connections.
REAR PANEL OUTPUTS
Three Pin XLR: This output is a fully balanced. It is the output used for recording and for connecting to
power ampliers with XLR connections. It is aected by the switches on either side of it. Warning: do
not connect this to mixers with 48+ volt phantom power: it will damage the preamplier.
Balanced TRS Output: This output is a 1/4” TRS connector used for TRS input power ampliers or any
other TRS input device. This output has 6 dB more output than the unbalanced output in the balanced
mode. If used in the unbalanced (ring grounded) mode this output is 3 dB louder than the unbalanced
out.
Unbalance output: this output is designed for connection to power ampliers or other devices with unbalanced inputs. It has 3 dB to 6 dB less output than the balanced output. Note: if for any reason there
is damage done to the balanced output system (i.e. phantom power) this output will still work.
REAR PANEL EFFECTS LOOP
Send: this output connects to the input of your eects unit (compressor, delay etc.). The level controls
for this output are on the front panel.
Return: this input is connected to the output of your eects unit. The level controls for this input are on
the front panel.
Tuner output: This output is designed for connection to your tuner. It is not aected by the mute switch
or the volume control of the preamplier.
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