This Tentlabs Heater Supply has been designed tu supply the heater of indirectly heated tubes, but can also be used for other applications to keep hum and noise to a minimal level.

The module is very compact and has a very low voltage drop. From the supplied AC voltage this module will generate a stable DC voltage. The module can supply a stable 1A 6.3VDC voltage from a 6.3VAC transformer winding.

Technology

The Tentlabs heater supply is designed to supply the heaters of indirectly heated tubes. Its main use is feeding phono and linestage tubes, to keep hum levels down. The module can also be applied to feed other circuits.

The heater supply uses schottky barrier diodes for rectification. They provide clean switching and have a low voltage drop. 2 filter capacitors (4700uF each) smooth the voltage. A discrete design, low drop voltage regulator feeds the powertransfo=istor at the output. 

With a 10-turns potentiometer the output voltage can be adjusted very precisely.

More tubes can be used in parallel, assumed that their heaters are at equal potential. When heater potentials are different, seperate modules (and transformer windings for each module) are necessary.

Specifications

Electrical 

• Output adjustable between 2.5V and 13V, 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.