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Specifications Mechanical: Tube PCB with 10mm Standoffs (10mm standoffs are required and 10mm clearance must be present below the PCB): 140mm deep 80mm wide 45mm high Fixing holes in the four corners on a 71mm X 131mm rectangle. Fixing holes require M3 or equivalent screws. Mains transformer: 76mm diameter 40mm high Fixing with either centralRead More

1.1 – Settings and Input wiring for use as SE Linestage 6db Gain This type of Application requires the following jumper settings: The input connections should follow the Scheme shown underneath: Includes: 1 pc UTS 1 set 70 x 240 x 240mm chassis with faceplate drilled 1 Universal tube Stage including transformer mounted 1 TeslaRead More

1.2 – Settings and Input wiring for use as SE Linestage 12db Gain This type of Application requires the following jumper settings: The input connections should follow the Scheme shown underneath:

Bias voltage A negative bias voltage is needed to prevent runaway current in a vacuum tube. The negative voltage can be applied to the cathode or to the grid.   1. Cathode bias: When applied to the cathode, it becomes self biasing, and the Anode voltage needs to be increased by the amount of voltageRead More

Active Bias Control The ideal solution to fixed bias stability is to use an electronic circuit to actively sense current flow through the tube.   Benefits: tube life is extended, saturation of the output transformer is avoided, amplifier always operates optimally, better bass performance, more dynamics, danger of runaway tube current when amplifier is unattended isRead More

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 betterRead More

Circuit and wiring connections as follows:

Discussion: Requirements:   To use the ABS Module, the amplifier must have the following:   1. At least one 6.3V….15V AC winding that has either one side grounded or is floating (not connected to ground at all – can be tested using a multimeter). If one side of the AC filament winding is grounded then thisRead More

ABS Supply Principle  ● The reference voltage is developed across an exchangeable resistor which can also be an external adjustable resistor ● The control loop adjusts the bias such that current through the sampling resistor (10R) produces the same voltage as the reference voltage, but it does so extremely slowly, to reject the dynamic variationsRead More

–The Audio Matrix PCB –The Control Matrix PCB The diyhifisupply® Ultimate Volume Control (UVC) has been designed to offer a State of the Art volume control and input switching selection. It is intended to be applied to integrated amplifiers and preamplifiers, to be used with any compatible following active stage. The Ultimate Volume Control isRead More