ABS Module Features

  • Eliminates need for constant re-adjustment of Bias to compensate for mains variations and valve aging
  • Regulation of cathode current of tubes from around 1mA to 250mA with10R cathode resistor current match between halves depends on cathode resistor tolerance ± 1% due to circuit (typical mismatch << 0.1mA). Perfect current balance produces better bass
  • Current regulation is not influenced by music signal
  • Current set by standard 1/4W leaded resistor (exchangeable)
  • Current can be adjusted from 0mA to 90mA per tube if a 10K Pot is connected instead of the resistor
  • reduces noise on bias supply by at least 40db (100 times) so even the most basic bias supplies sound good.
  • Lower noise improves resolution and imaging
  • Turn on Delay of 45 Seconds
  • Slow ramp up of current over a further 45 Second
  • Fault Indication via LED’s (Red) on PCB; they can be re-mounted on the Amplifier chassis
  • Fault Indication via TTL compatible open collector output (can be used for additional protection circuitry or for our upcoming electronic choke PSU PCB)
  • multiple mounting holes for easy mounting
  • Can be fitted to any existing fixed bias equipped Amplifier without changing the original circuit and with absolutely minimal modifications, except bias potentiometers (and possibly cathode resistor changes)
  • Small size due to use of existing supplies already present in your amplifier
  • No high voltage connections are required to be made

Electrical Parameters

  • Maximum Tube current up to 250mA with 10R Cathode resistors
  • Output voltage up to -150V (depending upon the original bias supply in the amplifier)
  • Outputs can sink at least 2mA current or much more
  • Requires a single, ground referenced 6.3V to 12.6V AC supply (ie power tube filament supply draws 60-100ma) for the actual module and the original negative bias supply of the Amplifier

Mounting And Installation

  • Designed for easy installation: one module can control two power tubes.
  • The only connecting voltage is needed are the existing DC 70 — 130 V bias voltage,a 6.3 — 12V AC connection (taken from the filament supply of the power tube {note: must not be a center tapped winding unless the winding is disconnected and if one side of AC winding is grounded then THAT side must connect to pin 4 of the ABS module} current draw 60ma/100ma—6.3v/12.6v)), and then a single connection to the grid and cathode of each tube to be controlled.
  • Designed to fit right into the current Ella chassis with no special mounting hardware or fixtures needed.