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Bolec DB1-128 Signal Amplifier and Divider 12/24VDC


The BOLEC DB1-128

A versatile signal amplifier/divider designed for use with standard automotive and diesel speedometers and tachometers in various applications such as marine, automotive, commercial vehicles, tractors, and generator sets. It is compatible with signals generated by magnetic pickups, alternator AC connections, or electronic ignition auxiliary signals.

Key features of the DB1-128 include:

  1. Signal Enhancement: It can boost weak signals received from these systems to produce a +supply voltage peak-to-peak square wave, suitable for most instrument inputs.
  2. Frequency Adjustment: The unit can also reduce the signal frequency by factors of 1, 2, 4, 8, 16, 32, 64, or 128, making it easier to adjust the connected instrument.
  3. Installation: It is recommended that a qualified automotive electrician or instrument technician install the DB1-128. While it is designed to be a universal signal processor, it may not be suitable for all applications. The manufacturer is not responsible for incorrect installation or any damage caused during installation.


  • Dimensions: Approximately 58 x 42 x 23mm
  • Voltage: 12/24 Volt DC Negative Ground systems
  • Input Range: Signal amplitude 2+v p-p, sine or square wave. Frequency at 0 – 10KHz
  • Output Rating: Square wave at +supply, rise time ≤40uS. Switch at divide input freq. by 1, 2, 4, 8, 16, 32, 64, or 128

** SIGNAL ** The DB1-128 is a general purpose module designed to work with most standard automotive or diesel speedo’s and  tachometers as used in marine, automotive, and commercial vehicles, tractors, generator sets, etc. These are usually driven by a magnetic pickup, alternator AC connection or electronic ignition auxiliary signal. This unit will take the weaker signals often received from these systems and boost them to a 12v p-p square wave suitable for most inputs. The signal may also be reduced in frequency by a factor of 1, 2, 4, 8, 16, 32, 64 or 128 so as to allow easier adjustment of the driven instrument.

Installation Instructions:

  1. Mount the DB1-128 control module in a suitable location on the instrument panel using double-sided tape or a neutral cure silicone sealant.
  2. Connect “IGN+” to a switched ignition supply line, preferably through a 2 Amp fuse.
  3. Connect “GND” to a good ground or earth connection.
  4. Connect “INPUT” to the signal source, typically the active wire of the magnetic pickup or signal source.
  5. Connect “OUTPUT” from the DB1-128 to the signal terminal or input on your instrument.


Ratio Switch Settings

Specsheet: Download PDF
Instruction Manual: Download PDF

The document also includes a wiring diagram and a caution to avoid having more than one switch set on at a time when using the DB1-128. Proper installation and wiring are crucial to ensure its correct functioning with your instrument.

For further details, please contact us – sales@bolec.com.au


Signal Amplifier
Signal Amplifier

Bolec Electronics

Founded in 1978, Bolec Electronics has developed a portfolio of over 80 products and a reputation that survive and thrive in some of Australia's harshest environments. Bolec Electronics is the OE supplier to some of the world's largest truck and engine manufactures.

Premium quality

Easy to install


Designed and made in Australia