Entry Point
User Guide
May 2012
Rev. B
Introduction:
The Eurorack platform is rich in sound shaping tools that can be used to create new and innovative effects for
stringed instruments. The Entry Point allows you to take advantage of this sonic landscape by acting as a bridge
between your electric or bass guitar and Eurorack modular synthesizer. Instead of buying a single effect pedal
to achieve a desired sound, now you can patch multiple modules to build your own unique effects with the
individual characteristics you desire. The Entry Point performs three primary functions when connecting your
instrument to a Eurorack system. First, it acts as a low noise preamplifier to bring your instrument up to
Eurorack signal levels. Second, it generates an envelope voltage that follows your playing dynamics for use as a
control voltage. Third, it extracts the fundamental frequency of the note played and outputs it as a square
wave signal for processing in the modular.
Preamplifier:
The Entry Point's preamplifier is designed to amplify musical instruments up to Eurorack signal levels. When
connecting traditional passive instruments or other low signal level devices, the ACTIVE/PASSIVE switch should
be set to the passive position. When connecting active instruments or other devices that output line level
signals the switch should be set to the active position. The switch position affects both the envelope follower
and the square wave generator and should be set prior to making any other adjustments. The GAIN control
knob sets the amplitude of the signal coming out of the the SIG jack. The amplitude of the SIG output is
displayed on the LED signal strength meter.
Envelope Follower:
The envelope follower generates a control voltage that correlates with the dynamics of your playing. An
envelope is output when the amplitude of the input signal is greater than the threshold set by the THRESH
knob. Exceeding the set threshold is displayed by illumination of the blue threshold LED. The RATIO control
sets the amount gain that is applied to the control signal that has exceeded threshold. A wide range of
envelope shapes can be achieved by the manipulation of these controls. For an envelope shape that follows the
overall dynamics of the input signal, the THRESH control should be set to the minimum threshold (full
clockwise) and the RATIO control should be adjusted to set the maximum envelope size. To create an envelope
that responds to the most dynamic parts of the input signal, raise the THRESH control so the threshold LED
illuminates only on the loudest parts of the input signal. Then adjust the RATIO control for the desired
envelope amplitude. The envelope follower control voltage is available as both a positive control ENV + and
negative control ENV - . The range on the ENV + output is 0 to 5V and the range on the ENV – is 5V to 0 or 0 to
-5V as set by H101.
ENV – : 5V down to 0V (default configuration) ENV – : 0V down to -5V (user option)
Square Wave Generator:
The square wave generator extracts the fundamental frequency of the single note being played and outputs it
as a ±5V square wave on the SQR jack. The TRACK control knob allows for adjustments to be made to the bias
of the extraction circuit. When this control is in the counterclockwise position the circuit is very sensitive and
an output can be triggered with an extremely light touch. As the control is rotated clockwise, the sensitivity is
reduced resulting in more precise tracking; however the sustain of a note will be shortened. The quality of the
tracking is largely dependent on a number of factors such as the instrument configuration, setup, and playing
technique. Playing with a soft touch and using only the neck pickup will generally offer good results. Poor
tracking will result in an output that jumps between the fundamental and the second harmonic (octave up). At
times this might be just the thing you're looking for, so have at it.
1. Instrument Input
1/4” phone jack input for connection to both passive and
active instruments.
2. Active/Passive Selector Switch
Selects the amount of gain required to bring your instrument's
output up to a line level signal. For passive instruments with
standard high impedance pickups the switch should be set to
PASSIVE for best results. When using instruments with onboard active electronics or when feeding the Entry Point from
the output of an external preamplifier, the switch should be
set in active mode. Some instruments with active pickups
(like EMG) produce relatively low output signals and may
work best in passive mode. Since every instrument is
different experimentation is encouraged.
3. Output Level Control
Sets the output level for the 3.5mm SIG jack. The required
output level is dependent on the next module in the
processing chain. Experiment with driving filters and other
modules with different amounts of gain to broaden your
sound palette. Once you find the sweet-spot for a particular
module, note the LED metering level for repeatability.
4. Output Level Metering
The LED output metering provides a visual feedback for the proper level settings. The meter is particularly
valuable when playing live as it allows you to quickly setup your system based on predetermined levels.
5. Fundamental Tracking
The TRACK control is used to set the bias for the fundamental extractor. In the counterclockwise position the
extractor is at it's most sensitive setting. In this position the extractor may be unreliable when tracking low
frequency notes and open strings. This will be evident by the note jumping between the fundamental and an
octave above the fundamental. As the control is rotated clockwise, tracking will improve but the sustain will
be shortened.
6. Envelope Threshold
The envelope threshold control THRESH is used to set the minimum signal necessary before an envelope is
created. Once the input signal crosses the set threshold level, an envelope will be present on the ENV+ and
ENV- jacks. The amplitude of the envelope will be the amount of signal over threshold multiplied by the ratio.
The blue led illuminates when threshold has been exceeded.
7. Envelope Ratio
The ratio control sets the gain for the envelope follower. Large envelope ratios allow for the generation of
envelopes that span the full control range on input signals that just barley exceed the threshold.
8. Output Group
3.5mm output jacks for interfacing with Eurorack modules. The SIG jack delivers a clean Eurorack level
representation of your instrument's output. The SQR jack is the square wave output of the fundamental
extractor. The ENV+ and ENV- jacks output the rising and falling envelope control voltages. The rising envelope
is 0V to 5V and the falling envelope is 5V to 0V or 0V to -5V.
9. Balanced Output
This output provides a line level balanced copy of the input signal. The jack is TRS balanced with the tip
connected to the in phase signal and the ring to the -180° signal. It is safe to use a standard TS instrument
cable if an un-balanced output is needed.
Specifications:
Form Factor - Panel Size: 10 HP Eurorack panel
Depth (Back of panel to Max): 35mm (1.38”)
Power - Connector: Eurorack 16 pin keyed header
+5V: Not Used
+12V: 55mA Max Consumption
-12V: 55mA Max Consumption
Max Operating Voltage: ±15V
Electrical - Instrument Input:
Connector: 1/4” TS Phone Jack (Unbalanced)
Input Impedance: 1 Meg Ω
Direct Output:
Connector: 1/4” TRS Phone Jack (Balanced Line Level)
Output Impedance: 470 Ω
THD + N (20Hz – 20kHz): < 0.002%
SNR (A-weighted): 112dB
Gain Passive +22dB Unbalanced
+28dB Balanced
Gain Active +6 dB Unbalanced
+12dB Balanced
Max Output Before Clipping: ±12V Rails - ±10Vpk (+19 dBm)
±15V Rails - ±13Vpk (+22 dBm)
Signal Output “SIG”:
Connector: 3.5 mm TS Jack (unbalanced)
Output Impedance: 470 Ω
THD + N (20Hz – 20kHz): < 0.002%
SNR (A-weighted): 110dB
Max Gain Passive +35dB
Max Gain Active +18dB
Max Output Before Clipping: ±12V Rails - ±10Vpk (+19 dBm)
±15V Rails - ±13Vpk (+22 dBm)
Square Wave Output “SQR”:
Connector: 3.5 mm TS Jack (unbalanced)
Output Impedance: 470 Ω Output Impedance
Output Signal: ±4.8Vpk (dc coupled)
Positive Envelope “ENV +”:
Connector: 3.5 mm TS Jack (unbalanced)
Output Impedance: 470 Ω Output Impedance
Envelope Detector: True RMS (THAT 2252)
Output Signal: 0V up-to 5.4V
Negative Envelope “ENV -”:
Connector: 3.5 mm TS Jack (unbalanced)
Output Impedance: 470 Ω Output Impedance
Output Signal: 5.4V down-to 0V or 0V down-to -5.4V (jmp opt)
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