TentLabs Tube heater Supply
This module is intended to supply the heaters of indirectly heated tubes. Their supply isn't half as critical as the supply of directly heated tubes. Why this module? It is compact, very low drop, does the full job from AC in to DC out over a range from 2.5V to 10V. It is able to supply a stable 1A 6.3V DC voltage from a 6.3Vac winding !
Purpose
TentLabs heater supply is designed to supply the heaters of indirectly heated tubes. Its' main use is feeding phono and linestage tubes, to keep the hum levels down. The module can also be applied to feed other circuits, like the CDpro CD drive used in our CD player. For this purpose a fast switch-off function is available.Technology
The heater supply uses Schottky barier diodes for rectification.
They provide clean switching and inhibit low voltage drop. 2 filter capacitors (4.700uF each) smooth the voltage. A discrete design, low drop voltage regulator feeds a power transistor at the output.
A tenturn timmer allows for accurate adjustment of the output voltage.
Application
More tubes can be connected in parallel, assumed their respective heaters are at equal potential. If heater potentials are different, separate modules (and transformer windings for each module) are required. The heater reference needs to be connected close to the tube The total output current is limited to 1.5Adc, mainly due to heat dissipation. The units are factory adjusted at your order. After installation, the supply needs no adjustment.A fine example of a Squeezebox power supply is shown here (Dutch only)
Specifications
Electrical• Output adjustable between 2.5V and 10V, specify when ordering
• Output current maximum 1.5A
• Input voltage should not exceed 1 V above specification (see application info - to be written)
• Minimum input voltage 4 Vac
• Output noise < tbd uVrms (10Hz - 20kHz)
• Output hum < tbd uVpeak at 100Hz / 120Hz
• Output impedance < tbd mOhm
• Fast switch-off function available on request (required if used to supply 9V section of philips CDpro CD drive)
• The heatsink is not electrically isolated from the circuit and should be isolated from the chassis
• The output is not short circuit proof
Mechanical
• Total size 40*60*40mm (W*L*H, heatsink included, standoffs excluded).
• Weight each 60 gram (excluding packaging)
• Hole pitch 31* 51mm, hole diameter 3.5mm
• Needs 8mm stand-offs to mount on chassis, supplied with modules.